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Updated: 8 hours 11 min ago

Addressing Cascadia Subduction Zone Great Earthquake Recurrence

Tue, 07/02/2019 - 11:24

Subduction zone earthquakes are among the most impactful natural hazards on Earth.

The Cascadia Subduction Zone (CSZ) of the U.S. Pacific Northwest and coastal British Columbia, Canada, experienced in prehistory numerous great megathrust earthquakes, which are defined as magnitude 8.0 and larger. Future earthquakes are inevitable, and their effects could cripple the region. Despite substantial knowledge gained from decades of geoscience research, estimates of the sizes and frequencies of Cascadia earthquakes remain uncertain.

Earthquake cycle models are commonly invoked along subduction zones, and earthquakes repeat with some degree of regularity from tectonic loading and release. However, estimated recurrence intervals of past Cascadia megathrust earthquakes vary substantially, and statistical and computer models suggest event clustering behavior.

Much of the current understanding of Cascadia earthquake hazards comes from evidence found in onshore and marine geologic records and from modern recurrence in other subduction zones. Differences between geologic records might be related to their sensitivity as earthquake recorders (i.e., “evidence thresholds”). For example, the occurrence and preservation of coseismic coastal subsidence depends on several parameters, including rupture extent, slip distribution, and interevent coastal uplift. Similarly, offshore turbidite records depend on the frequency and extent of ground motion shaking during past Cascadia earthquakes, as well as on sediment availability.

(a) The earthquake cycle paradigm in which tectonic strain is steadily accumulated and released over a characteristic time period. (b) An alternative clustered model in which strain is released during cascading earthquakes of variable magnitude, followed by a long hiatus of seismic quiescence. (c) Onshore records of great Cascadia earthquakes include a sudden coseismic shoreline elevation change in which coastal wetlands drop below sea level, leaving a stratigraphic record of subsidence and marine incursion. (d) Offshore coseismic turbidite generation in which sediment was deposited during periods of strong ground shaking. Turbidites found in sediment cores have been interpreted for CSZ megathrust recurrence. Credit: Lydia Staisch

The U.S. Geological Survey (USGS) Powell Center for Analysis and Synthesis Cascadia Earthquake Hazards Working Group was formed to synthesize geological and geophysical information relevant to CSZ megathrust earthquakes.

Participants include a diverse range of researchers, from early-career scientists to emeritus experts in tectonics, geophysics, crustal structures, landslides, sedimentology, paleoseismology, land level changes, geodesy, mantle and crustal rheology, and earthquake rupture dynamics. Throughout the first weeklong meeting in March 2019, risk communication experts were engaged to ensure that the particpants’ discoveries and uncertainties will be translated most effectively to communities and other stakeholders.

Presentations and group discussions were focused on earthquake cycle models of time-independent (Poisson) and time-dependent (both quasiperiodic and clustered) recurrences. The group concluded that time-independent megathrust recurrence was unlikely along Cascadia but that further synthesis and analysis of geologic records and geophysical measurements are needed to differentiate between quasiperiodic and clustered models. The meeting also focused on integrating CSZ data sets and discussing their relative evidence thresholds. These data sets are currently being integrated into an online geographic information system database.

Ongoing challenges remain: Potential segmentation along the CSZ and implications for how recurrence is quantified remain unclear, locking models are nonunique given current geodetic observations, and the contributions of aseismic slip, plastic deformation, and strain partitioning to the slip budget are unknown. Recommendations for a path forward on CSZ science include expanding seafloor geodesy, integrating onshore and offshore evidence within a Bayesian network, testing the sensitivity of available recurrence records, expanding coastal wetland carbon-14 chronologies, detecting interseismic land level changes, and rigorously exploring the plausible ranges of coupling models.

We thank Joan Gomberg, Janet Watt, and Jon Perkins for their dedication as co–principal investigators. Their guidance has contributed significantly to our project. We also thank our first meeting participants for their time and expertise.

—Lydia Staisch (lstaisch@usgs.gov), U.S. Geological Survey, Menlo Park, Calif.; Maureen Walton, U.S. Geological Survey, Santa Cruz, Calif.; and Rob Witter, U.S. Geological Survey, Anchorage, Alaska

Transcending Science: Can Artists Help Scientists Save the World?

Tue, 07/02/2019 - 11:23

Our climate crisis is more desperate than ever—ice caps are melting, disease is spreading, heat waves are multiplying, droughts are laying waste to crops and ecosystems, tropical storms are strengthening—and politicians continue to ignore the warning signs. It is no secret that the current administration in the United States is doing nothing to slow the amount of carbon dioxide pumped into the atmosphere every year, a decision that promises to have dire consequences.

Our collective understanding of human-caused climate change dates back over a century, beginning in 1896 when the Swedish scientist Svante Arrhenius first wrote of the link between carbon dioxide (which he called carbonic acid) in the atmosphere and global temperatures via the greenhouse effect.

In the past half century, sophisticated computer models have consistently demonstrated that the increasing concentration of carbon dioxide in the lower atmosphere—carbon dioxide that got there because of burning fossil fuels—has raised the globally averaged surface temperature by over a degree Celsius. This temperature rise, attributed almost entirely to human activity, has precipitated massive and rapid changes across the globe, and these changes are forecast to worsen in the future.

In 2018, the United Nations Intergovernmental Panel on Climate Change warned that we had about 12 years (11, now) to make massive, large-scale, revolutionary changes to our global economy to avoid the worst impacts of climate change.

Proximity to Revolutionary History

Artists and designers can help scientists both communicate climate science to the public more effectively and be better scientists.As a transgender woman living in America, I am no stranger to revolutionary movements. Fifty years ago, a group of queers, led in part by a few brave trans women of color, started a riot at a bar in New York City. That uprising ultimately initiated the LGBT rights movement, a movement that has seen many monumental successes punctuated by several devastating losses and setbacks.

After considering my proximity to this revolutionary history, in 2017 I left a position as a research climate scientist at the NASA Jet Propulsion Laboratory (JPL) to teach climate change at an art institution, the School of the Art Institute of Chicago.

I made the switch for several reasons, but first and foremost, I wanted to dedicate the remainder of my career to exploring nontraditional ways of bridging divides between scientists, artists, and the public. I took this opportunity as a conscious effort to contribute to a solution to the climate crisis.

Now my career is dedicated to exploring ways artists and designers can help scientists both communicate climate science to the public more effectively and be better scientists.

Collaboration and Engagement

This excerpt from David George Haskell’s “Notes on Ecological Aesthetics and Ethics” inspires me in this effort, daily:

Once we—collectively—have an integrated sense of aesthetics, we can begin to discern what is beautiful and what is broken about a place, and, from there, I believe we can begin to form an objective—or near-objective—foundation for ethical discernment. Answers emerge from the community of life itself, filtered through human experience and consciousness.

In recent decades, though the knowledge of climate change has continued to expand, much of this knowledge remains abstruse, cumbersomely documented, and unintuitively presented, making engagement with it by “nonscientists” difficult. Perhaps this is the reason why a large segment of the general population remains convinced that human beings have not caused the observed 20th and 21st century climate change.

There exists, therefore, an exciting and necessary opportunity for scientists to collaborate with artists. Many scholars learn that the scientific method begins with a hypothesis, progresses through research and analysis, and concludes with a result. The design process, in contrast, begins with human engagement and inquiry, progresses through ideation and prototyping, and concludes with a refined artifact.

In this moment, especially in the field of climate science, we need, more than ever, for the public to engage with science.It is precisely through the initial step of human engagement where artists and designers distinguish themselves from (most) scientists. And, as Haskell writes above, “once we…have an integrated sense of aesthetics, we can begin to discern what is beautiful and what is broken about a place.” Perhaps artists can, in fact, help scientists be better scientists.

I maintain that the unique insights of artists, designers, and makers present an opportunity for scientists to collaborate in the creation of evocative visual and auditory artifacts that invite the public to share in both the research process and the scientific conclusions of a study. These collaborations ultimately engender a more thorough and straightforward understanding of scientific knowledge.

In this moment, especially in the field of climate science, we need, more than ever, for the public to engage with science. Through inviting and evocative designs that tell the story of the data in a more intuitive way, we can better foment the magnitude of the climate crisis in the public psyche and, ultimately, encourage people to invest in the necessary solutions. This public buy-in would go a long way toward productively addressing the climate dilemma.

Data Visualization and Better Science

It is perhaps intuitive that art and design can help scientists better communicate their results to the public.

However, I maintain that improvements in data visualization (through collaboration with artists and designers) can also facilitate exploratory research and help researchers ask qualitatively “better” scientific questions. Exploratory analysis, or a precursory evaluation of data with the intent of generating a research inquiry or hypothesis, is often hampered in efficacy by an arduous data-parsing process or incomplete and confusing data visualization.

As we update our understanding of the environment, we must also update the tools we use to study it and the methods we use to present it to the public.As a case study, I worked with Adrian Galvin, a designer at JPL, to develop a data interface and visualization tool for the Multi-angle Imaging Spectroradiometer (MISR) smoke plume project, a unique and valuable data set often overlooked because of its inaccessible interface. Together, we conducted a thorough workflow inquiry and iterative prototyping sessions to refine interactions and visual representations. The interface redesign that resulted from this process streamlined exploratory investigation and reduced the time taken to generate visualizations and correlations on the order of days. The result of these efforts facilitated better science.

Through this project, Adrian and I hypothesize that similar human-centered art and design processes can critically enhance the practical value of many Earth and climate science data sets. As we update our understanding of the environment, we must also update the tools we use to study it and the methods we use to present it to the public. There is real potential for art and design to dramatically improve the way climate research is conducted and communicated.

A New Chance to be Truly Revolutionary

Fifty years ago, queer folks began a revolution that demanded that we be respected as equals—both in life and in law—and that revolution has resulted in enormous progress for LGBT+ people everywhere.

On the last day of class, I tell all my students that the climate dilemma offers another opportunity for us to be truly revolutionary. Through collaboration with artists and designers, we can work toward the demystification of climate science because when science becomes understandable to the public, people become interested in not only the results but the scientific process, discussions, and, most importantly, solutions.

It is my hope that we will follow in the footsteps of our revolutionary ancestors and solve the climate crisis, together.

—Mika Tosca (@climategal84), School of the Art Institute of Chicago, Chicago, Ill.

Recycled Glasses Connect Eclipse Watchers Across the Equator

Tue, 07/02/2019 - 11:17

Today millions of people in southern South America will have the chance to see a total solar eclipse. Among them are tens of thousands who will view the eclipse through a pair of recycled eclipse glasses.

After the 2017 Great American Eclipse, the nonprofit group Astronomers Without Borders (AWB) facilitated the collection of more than 5 million solar eclipse glasses from more than 1,000 collection sites around the country. AWB wanted to give those glasses new homes.

“We thought that people would be sending them in in small batches,” AWB president Mike Simmons told NPR. “But as it turns out, we were contacted by people all over the country who said, ‘We’d like to collect glasses for you. How do we become a collection center?’”

Astronomers Without Borders volunteers sorted through donated eclipse glasses and vetted them for safety and quality. Credit: Astronomers Without Borders

The millions of donated glasses ultimately made their way to a single warehouse in Arkansas. There, a dedicated group of volunteers individually checked each pair to make sure it was safe to use, in good shape, and not fraudulent. Glasses the volunteers deemed good enough to reuse were saved from a premature trip to a landfill.

More than 43,000 glasses made the cut in time to be shipped to Peru, Chile, and Argentina for today’s total solar eclipse. AWB worked with the U.S. embassies in those countries to get glasses to schools, universities, planetariums, and people living along the path of totality.

The collection effort wasn’t the first eclipse glasses recycling program that AWB has undertaken, but it certainly was the largest, Simmons said, thanks in large part to the plethora of donations from U.S. eclipse viewers.

“People were really into it,” Simmons said. “They loved the idea of being able to share the experience they had with kids in other countries where they wouldn’t be able to get the eclipse glasses.”

Not all of the donated glasses were vetted in time for Great South American Eclipse 2019. AWB is working to sort through more of the glasses in time for an annular solar eclipse in December that will be visible in the Middle East and Asia.

For today’s event, AWB also helped arrange two eclipse workshops, one for teachers and one for students, to connect U.S. eclipse viewers with those in Chile and demonstrate that awe of the sky is a universal experience.

You can watch today’s total eclipse through a livestream from Chile.

—Kimberly M. S. Cartier (@AstroKimCartier), Staff Writer

Climate Solutions Caucus Provides Bipartisan Forum

Tue, 07/02/2019 - 11:15

The recent relaunch of the congressional Climate Solutions Caucus keeps alive an important bipartisan forum on climate change, says Mark Reynolds, executive director of the Citizens’ Climate Lobby (CCL), an advocacy group that helped to found the caucus and supports its efforts.

The House caucus, which was weakened with the 2018 election defeat of its then cochair, former Rep. Carlos Curbelo (R-Fla.), and other Republican caucus members, relaunched on 20 June with 22 Republican and 41 Democratic members.

That’s down from the last congressional session when there were 90 members equally divided between Republicans and Democrats. Rep. Ted Deutch (D-Fla.) continues as the Democratic cochair, with Rep. Francis Rooney (R-Fla.) taking Curbelo’s place as the Republican cochair.

“The Climate Solutions Caucus can help to tamp down those partisan tendencies on climate change and make it a bridge issue instead of a wedge issue.”“As we head into a presidential election, the tendency is to ratchet up partisan rhetoric, which can be an obstacle to enacting solutions to climate change. The Climate Solutions Caucus can help to tamp down those partisan tendencies on climate change and make it a bridge issue instead of a wedge issue,” Reynolds told Eos. “We need buy-in from both parties to have any chance of enacting solutions.”

The caucus was established in 2016 to educate members of Congress about climate change threats to the economy, security, environment, and infrastructure and to explore bipartisan and economically viable policy options.

In relaunching the caucus, Deutch said, “Americans want Congress to act on climate change. But we’re not going to get anywhere without bipartisan support.”

Rooney noted that “sea level rise, carbon emissions, and the overall health of our climate are bipartisan issues and I am encouraged that there are a growing number of people on both sides of the aisle willing to find solutions.”

Finding Areas of Common Ground

The top priority for the caucus should be to find areas of common ground where Republicans and Democrats can come together on bipartisan solutions, Reynolds said. “There are a number of bipartisan bills introduced to take small steps toward addressing climate change,” he said. “Getting the caucus to support these small steps could eventually lead to the caucus playing a role in bigger steps.”

Reynolds said that the biggest disappointment from the last Congress was that the caucus “didn’t get more support from the wider climate community. How many spaces are there where both parties can come together in respectful and appreciative dialogue on this most important of issues?”

In the past, some members of Congress have been accused of joining the caucus to “greenwash” their weak political records on climate change. However, Reynolds said that members of Congress shouldn’t consider the caucus as a way to mask a poor record.

“If a member of the caucus is not actively engaged in working on solutions, their opponent in the next election will be quick to point that out,” Reynolds said. “Simply being a member of the caucus will not provide political cover for them. Joining the caucus is just the first step toward climate leadership.”

—Randy Showstack (@RandyShowstack), Staff Writer

Spacecraft 107’s Big Trip

Mon, 07/01/2019 - 13:06

Scribbled in ballpoint pen on an equipment bay panel in pilot Michael Collins’s handwriting are the words

……..Spacecraft 107, alias Apollo 11, alias “Columbia.” ……..The Best Ship to Come Down the Line.

For all that we celebrate the feat of engineering of the first Moon landing, it hits us hardest when we remember how human it all was.

If it’s hard to imagine walking on the Moon, we can easily imagine Collins’s immense pride as he rode the USS Hornet to Hawaii after splashdown, uncapping his pen to leave behind a mark that commemorated this wild mission. (Technology later revealed it was twice the pride: Three-dimensional imaging of Columbia, Apollo 11’s command module, by the Smithsonian Institution in 2016 revealed that Collins came back to the ship later, likely while he was in quarantine at the Johnson Space Center, and wrote over his note again to preserve it.)

AGU has the honor of celebrating the 50th anniversary of the first Moon landing along with our own Centennial.AGU has the honor of celebrating the 50th anniversary of the first Moon landing along with our own Centennial. Join us at the National Archives in Washington, D.C., on 17 July when AGU will be sponsoring a geology panel discussion, “Small Steps and Giant Leaps: How Apollo 11 Shaped Our Understanding of Earth and Beyond.”

We also celebrate the legacy of Apollo in the pages of Eos. Our cover story looks at the science that came out of the 382 kilograms of Moon rocks hauled back by the astronauts. As recently as this past January, scientists announced a new discovery from the Apollo 14 mission: zircon grains common to Earth but unique to the Moon—which is to say, lunar-roving astronauts may have brought back an Earth meteorite!

NASA researchers had the foresight not to put all these alien treasures under the microscope as soon as they got their hands on them—a portion was held back and protected from our atmosphere so that today’s scientists could use modern technology on untouched specimens. We know we’re not alone in our excitement at what they might discover about our closest planetary neighbor.

While we reflect on how those space missions changed so much about the way we view our place in the universe, we continue to be inspired by new opportunities for exploration. Telepresence, wherein astronauts in orbit around the Moon or Mars would guide robots on the ground, is shaping up to be the next big thing in space exploration. Meanwhile, experts here on Earth are first guiding this technology underground. Read about a team testing robots that can autonomously navigate through flooded mines. The idea is less romantic, perhaps—there’s no one to call back that the Eagle has landed—but sending in robots to such treacherously dangerous terrain is likely the best way to keep pushing our boundaries of exploration.

Our forays into space technology have led us to new adventures on Earth as well.Our forays into space technology have led us to new adventures on Earth as well. Geoid anomaly maps created by satellite observations have revealed strangeness in the Indian Ocean. Read about the Indian research team that is on the hunt for the “missing mass” that will explain the largest geoid anomaly in the world. Theories abound: Is the anomaly due to structural undulation in the core-mantle boundary? Seismic low-velocity anomalies in the upper mantle? A “slab graveyard” in the lower mantle? To find out, the team headed to the source and deployed seismic sensors to record data for a year. We eagerly await their results.

Behind all science is the excitement of exploration and the thrill of discovery. In every issue, Eos dedicates its final page to such adventurers with Postcards from the Field. This month we hear from a team hand digging paleoseismic trenches in the Teton Range.

We urge you all to keep exploring, keep discovering—and send us a postcard!

—Heather Goss (@heathermg), Editor in Chief

Apollo’s Legacy: 50 Years of Lunar Geology

Mon, 07/01/2019 - 12:58

July 20, 1969, will forever be carved into the history books: the day that humankind took its first small step into the cosmos. The dawn of a new scientific era came just 4 days later.

When Apollo 11 splashed down on 24 July, planetary scientists knew they would soon get their hands on the first samples of material brought back from the surface of the Moon.

Apollo 11 astronaut Neil Armstrong collected a contingency sample of the lunar surface just after taking the first steps on the Moon. He stored the sample in his pocket in case they needed to make a quick departure. Credit: NASA

Apollo 11 astronauts brought back a scant 22 kilograms of material for scientists to study. Each subsequent Apollo mission—except Apollo 13, of course—brought back more and more rocks, soil samples, and drill cores. All told, the Apollo astronauts carried back to Earth 382 kilograms from six different areas of the Moon’s surface, each sample stored in a container that preserved a Moon-like environment.

The earliest looks at the Apollo samples proved for the first time some facts about the Moon that may seem obvious today: There is not now and there likely never has been life on the Moon, meteor impacts throughout the Moon’s history have pulverized the surface, and the Moon and Earth share many geochemical similarities.

But technology, computer power, and scientific knowledge have grown exponentially since humans last stepped foot on the Moon in 1972. Thanks to the foresight of NASA leaders of the time, some of the Apollo samples were curated so that future scientists could study pieces of the Moon that hadn’t been exposed to Earth’s atmosphere.

“What we like to say is that sample return missions allow scientists not yet born to use instruments not yet developed to answer questions not yet asked.”“What we like to say is that sample return missions allow scientists not yet born to use instruments not yet developed to answer questions not yet asked,” Jamie Elsila, an astrochemist at NASA Goddard Space Flight Center in Greenbelt, Md., told Eos.

Today, “we’re asking some of the same questions that the scientists back then were asking,” Elsila said. “Because [NASA] preserved these samples and curated them carefully, now we’re able to go back and try to answer these questions.”

As post-Apollo scientists studied carefully doled out lunar samples, they discovered much more about the Moon and its history than scientists of the 1970s could have. Here are some of the most notable discoveries about our celestial neighbor that have come from Apollo samples over the past 50 years.

The Rough Life of Lunar Regolith

Life as a soil grain on the lunar surface is tough. Nowadays, it’s rare for a large impact to happen on the Moon, but microscopic impacts happen all the time.

“The lunar regolith is being bombarded by micrometeorites and high-energy particles from the solar wind,” explained Richard Walroth, an instrument developer at NASA Ames Research Center in Mountain View, Calif.

Earth’s atmosphere protects its surface from these microscopic hits. On the airless Moon, however, tiny meteorites, cosmic rays, and superfast ions from the Sun constantly strike the surface.

This process, called space weathering, makes the lunar regolith literally rough around the edges.

“The grains melt at the very edge and form things called agglutinates,” Walroth said, which are mineral fragments fused together by glass. “They also get a little nanophase iron too. They’re like nanoscale droplets, essentially of metallic iron in glass.”

Walroth and his team have developed instruments to look at the mineralogy and weathering of agglutinates and other Apollo samples.

Apollo 17 astronaut Harrison Schmitt (seen here) collected samples of lunar regolith beneath the shadows of large boulders. The boulders partially shielded the regolith from micrometeorite impacts and some of the effects of space weathering. Credit: NASA/Marshall Space Flight Center History Office

The samples returned by Apollo astronauts bear the scars of space weathering, but some of the regolith samples were shielded from one type of weathering for millions of years.

“Shadowed soils…were collected at the surface but underneath the overhangs of boulders,” said Barbara Cohen, a planetary scientist at NASA Goddard Space Flight Center. “In that case, we think that they were shadowed from things like micrometeorite impacts, but they were still exposed sometimes over seasonal and day-and-night cycles to things like solar wind.”

“They might have a different total exposure history” than soils that were exposed to all types of space weathering processes, Cohen said. Comparing soils collected in different places will help Cohen and her team tease out which processes cause the different weathering signatures they see in Apollo samples.

“Space weathering is a global process,” Walroth said, but “every part of the Moon’s going to get affected by it a little bit differently.”

Something Old, Something Slightly Less Old

It turns out that lunar rocks become discolored as they age, and close-up study of the Apollo samples helped explain why.

“Space weathering is a really complex set of processes that affect these grains very much at the nanoscale,” Katherine Burgess, a geologist at the U.S. Naval Research Laboratory in Washington, D.C., told Eos. Burgess uses transmission electron microscopy to study how weathering chemically alters the surfaces of planetary bodies.

These typical lunar soil agglutinates are from Apollo 11 lunar sample 10084. (a) NASA photo S69-54827, an optical microscope photograph of a number of agglutinates with a variety of irregular shapes. (b) NASA photo S87-38812, a scanning electron photomicrograph of a ring-shaped agglutinate with a glassy surface coated with small soil fragments. Credit: The Lunar Sourcebook, via Lunar and Planetary Institute

Space weathering processes “have huge impacts in how planetary bodies look spectroscopically from spacecraft and telescopes and change their optical properties,” she explained. “That’s generally referred to as reddening or darkening.”

By studying the Apollo samples over the past 50 years, “we’ve figured out that the main cause of these optical changes is the formation of [nanophase iron] rims that are up to a couple of hundred nanometers thick,” Burgess said.

How much a grain has been altered by weathering processes can tell researchers how long it was left exposed on the surface. This is key to understanding the Moon’s geologic history and how long it takes for surface rocks to be buried underground.

You know, we say that Neil Armstrong’s boot prints will be there forever, but in reality, they are eventually going to be buried by all the regolith. It’ll just take a long time.“You know, we say that Neil Armstrong’s boot prints will be there forever,” Walroth said, “but in reality, they are eventually going to be buried by all the regolith. It’ll just take a long time.”

What’s become clear to lunar geologists is that apart from large and small meteorite impacts that churn up the regolith, the Moon’s surface is still aging, just very slowly.

“These are processes that take place over millions of years,” he said.

Change on the (Solar) Wind

Space weathering does more than just rough up the lunar regolith, said planetary geologist Natalie Curran. It can also change the regolith’s composition.

“Cosmic rays from outside of the solar system produce noble gases in these samples,” said Curran, who works at NASA Goddard Space Flight Center. “The cosmic rays basically interact with elements in the rock—so things like oxygen, silicon, or magnesium—and they form actual noble gases.”

“There were very relatively low abundances of noble gases in the rock to start with,” she said, because the Moon’s original stock of volatile gases is long lost to space. “So the more exposed to the space environment and the more cosmic rays hit that sample, the more isotopes of noble gases are produced.”

The Sun, too, has its own noble gases to impart to the Moon’s surface through the solar wind.

Solar wind noble gases “get implanted into the surface of these very, very small grains, and they have a different isotope ratio to what the cosmic ray–produced noble gases have,” Curran said. “So we can measure all these noble gases in a sample and then look at the different isotopes to see which noble gas is produced from each of the different reservoirs.”

Noble gas analysis is another way that scientists can learn more about the signatures of different space weathering processes. Curran and Cohen are working to do just that.

“We’re interested in seeing the differences between things that are completely exposed all the time and these things that were partially eclipsed by boulders at some point in their history,” Cohen said. “If some effects shut off and others keep going, then we would be able to say, ‘Oh, that’s what the signature of this other effect looks like.’”

Glass, Glass Everywhere

The lunar surface might seem to be all shades of gray, but that’s definitely not the case everywhere on the Moon. Apollo 17 astronauts Harrison Schmitt and Eugene Cernan and CapCom Robert Parker learned this firsthand. The video on the right is a recording from the moment of the discovery. Here’s a short excerpt from the recording’s transcript:

          Schmitt: It’s all over! Orange!

          Cernan: Don’t move it until I see it.

          Schmitt: I stirred it up with my feet.

          Cernan: Hey, it is! I can see it from here!

          Schmitt: It’s orange!

          Cernan: Wait a minute, let me put my visor up. It’s still orange!

          Schmitt: Sure it is! Crazy!

          Cernan: Orange!

          Schmitt: I’ve got to dig a trench, Houston.

          Parker: Copy that. I guess we’d better work fast.

          Cernan: Hey, he’s not going out of his wits. It really is.

          Parker: Is it the same color as cheese?

The orange soil is actually a deposit of microscopic orange glass mixed with the beige-gray regolith. These glass beads formed when ancient lunar “fire fountains” belched up molten magma, some of which condensed into droplets of pyroclastic glass and rained down onto the lunar surface 3.5 billion years ago.

Lunar sample 74220 is one sample of the orange soil discovered near Taurus-Littrow Valley during the Apollo 17 mission. A 2.1-millimeters-wide thin section of some of the glass is seen here in transmitted light. Credit: D. Kring/NASA/Lunar and Planetary Institute

“What most people don’t realize is that the soil on the Moon is about 20% glass beads” in the areas we’ve sampled, Darby Dyar, a planetary scientist at Mount Holyoke College in South Hadley, Mass., told Eos. Dyar, also at the Planetary Science Institute in Tucson, Ariz., has been studying lunar glass beads since she was in graduate school.

Apollo 15 samples contained similar glass beads that were tinted green. “What you see, is there’s about 5% to 20% of these little rounded glass beads which come from the volcanic glass fire fountains,” she said.

“The lunar soil is really fascinating in and of itself. The little glass beads are just one component of a really fascinating material,” Dyar said.

No Water Above but Traces Below

“At the time the Apollo samples came back,” Dyar said, “the techniques that we had to analyze them at that time indicated…that there was absolutely no water on the Moon. Certainly, no hydrous minerals, you know, no micas, no clay minerals, no amphibole.” On Earth, these minerals form in the presence of water.

Apollo 15 astronauts brought back regolith samples that included clods of green soil. Within the soil were small spheres of green volcanic glass, like these that were found in sample 15426. Credit: NASA/Johnson Space Center, Lunar and Planetary Institute

Other tests for lunar water looked at the ratios of different iron molecules. “That tells us something about how much oxygen was around when these materials formed,” she explained.

In a water-poor environment, iron will usually lose two electrons and exist in ferrous minerals, which are considered reduced. If there is any water around, that water can steal a third electron from ferrous minerals and create ferric compounds, which are oxidized.

“By 1980, the dogma was that the Moon was both completely dry and completely reduced,” Dyar said.

More advanced techniques and more sensitive instruments changed that dogma. Close looks into the volcanic glass beads found that they contain signatures of water, something that has been recently confirmed. And recent research has found that ionized hydrogen from the solar wind creates trace amounts of water in the lunar regolith.

“In the last decade, we’re suddenly revolutionizing our idea about what the interior of the Moon looks like.”“In the last decade, we’re suddenly revolutionizing our idea about what the interior of the Moon looks like,” Dyar said. “It looks like it might actually have had, at the time these were erupted, significant amounts of both water and oxygen around. That’s quite paradigm shifting.”

Amino Acids from Afar

“When the Apollo astronauts first brought these samples back,” Elsila said, “there was a lot of interest in understanding amino acids and potential organic compounds relevant to life in these samples.”

Although it is still unclear how life began on Earth, scientists thought it possible that the collision that formed the Moon out of Earth’s crust and mantle also could have transferred the building blocks of life to the Moon.

An Apollo 17 astronaut uses tongs to collect lunar sample 78501, one of the samples that was discovered to contain amino acids. Credit: NASA/Lunar and Planetary Institute

“In the 1970s, there were a lot of studies looking for amino acids in lunar samples, and they were detected, but the origins weren’t able to be determined at that point,” Elsila said.  There were fierce debates about whether the amino acids were really from the Moon or from accidental contamination.

A few years ago, Elsila led a team that reexamined amino acids in Apollo 16 and 17 samples to pinpoint their origins.

“We found that they were probably a combination of terrestrial contamination just from the sampling process and the curation process,” Elsila said, “but also some amino acids that seem to be indigenous to the lunar surface.” Lunar amino acids have a molecular structure distinctly different from terrestrial ones, her team found.

How did those amino acids get there? “The ones we found are similar to amino acids that we’ve detected in meteorites and other extraterrestrial materials that have probably undergone abiotic chemistry,” Elsila said.

Meteorites might have implanted those amino acids on the Moon long ago. Alternately, Elsila said, the molecules’ precursors might have blown in on the solar wind and undergone abiotic chemistry to form amino acids. Comparing lunar amino acids from areas exposed to impacts but not the solar wind and vice versa could help solve that mystery.

Investing in the Future

In the next few months, NASA will give scientists access to some never-before-studied Apollo samples. Those samples have never tasted Earth’s atmosphere. They’ve been kept in the same condition they were in when Apollo astronauts brought them back almost 50 years ago.

“Returned samples are an investment in the future.”“Returned samples are an investment in the future,” said Lori Glaze, acting director of NASA’s Planetary Science Division in Washington, D.C. “These samples were deliberately saved so we can take advantage of today’s more advanced and sophisticated technology to answer questions we didn’t know we needed to ask.”

The research teams NASA selected to look at the samples will work with one another to create a holistic view of the Moon’s geologic history as told by the Apollo program. Many of the necessary tests will change those samples forever. But lunar geologists are already looking toward future exploration and future sample return missions to answer our lingering questions about the Moon.

An elevation map of the Moon’s South Pole–Aitken basin, one of the largest and oldest impact basins in the solar system. Cool colors represent lower elevation, and warm colors represent higher elevation. The impact that formed this basin went so deep that it excavated material from the Moon’s mantle. Lunar geologists consider the South Pole–Aitken basin one of the most promising places left to explore on the Moon. Credit: NASA/GSFC/University of Arizona

“Unless you’re willing to put a rock on the lunar surface and wait a billion years,” Walroth said, “it’s going to be really hard to answer those questions. But that’s why we hope to get material from more and more places around the Moon.”

“Our Apollo samples all came from the nearside equatorial region,” Cohen said. “We didn’t have the context, the global context for them at the time that we sent those missions and got those rocks back. And so saying that we’ve really sampled the Moon, well, we really have only sampled a very small part of it.”

“There are lots of places left to go,” she said.

—Kimberly M. S. Cartier (@AstroKimCartier), Staff Writer

Spirits Are Flying High for Dragonfly and Titan

Fri, 06/28/2019 - 18:49

If you were anywhere near science Twitter yesterday afternoon, you might have heard the news:

WE’RE GONNA SEND A DRONE HELICOPTER ROBOT TO TITAN! #Dragonfly https://t.co/TpQYtZCsu7

— Katie Mack (@AstroKatie) June 27, 2019

NASA announced its next New Frontiers mission: Dragonfly, an automated drone that will fly the skies of Saturn’s largest moon, Titan. Dragonfly, led by planetary scientist Elizabeth “Zibi” Turtle of the Johns Hopkins University Applied Physics Laboratory in Laurel, Md., will be launched in 2026 and arrive at Titan in 2034.

The nuclear-powered robotic helicopter will spend a few years flitting from one sandy spot to another, sampling Titan’s hydrocarbon dunes, exploring craters and lake beds, and sniffing out signs of life.

Planetary scientists have been itching to get back to Titan since the Huygens probe landed there in 2005. So they were understandably ecstatic at the Dragonfly reveal:

How did #AbSciCon19 feel about the #Dragonfly announcement? Sound on pic.twitter.com/aCfG1ast8w

— Laura Fattaruso (@labtalk_laura) June 27, 2019

I think I’d honestly convinced myself we wouldn’t go back to Titan in my lifetime. I can’t stop crying tears of joy. We’re going to answer the questions that keep me up at night.

— Dr./Prof. Sarah Hörst (@PlanetDr) June 27, 2019

 

Scientists around the world overflowed with excitement…

Took this screenshot because I just loved my Twitter feed’s excitement. pic.twitter.com/SJ1EgkM1Ip

— Dr. Jessie Christiansen (@aussiastronomer) June 27, 2019

I'm in a British pub full of space nerds and we just all went nuts when the Titan #dragonfly mission was selected. Space is great.

— Jonathan O’Callaghan (@Astro_Jonny) June 27, 2019

There's going to be a coaxial quadcopter that can suck material into its mass spectrometer flying around in the atmosphere of the giant moon of Saturn. …I love living in the future #Dragonfly

— Michele Bannister (@astrokiwi) June 27, 2019

I'm living for Zibi's joy! #Dragonfly pic.twitter.com/eQPYGo4gMq

— James Tuttle Keane (@jtuttlekeane) June 27, 2019

 

…and Titan was happy to be getting a new friend:

pic.twitter.com/xdJvq4rMIc

— Alex Parker (@Alex_Parker) June 27, 2019

 

Some questioned the nature of reality:

I just checked pic.twitter.com/LOd4Ajq6jr

— Dr./Prof. Sarah Hörst (@PlanetDr) June 28, 2019

 

But Titan is so totally fetch…

Nobody:NASA: "Get in loser we're going to Saturn's moon" #dragonfly pic.twitter.com/WWAfuvOMEz

— Stephanie E Suarez (@geologiststephy) June 27, 2019

 

…that people immediately began celebrating humanity’s return to the most Earth-like place in the solar system:

When the #Dragonfly @JHUAPL crew gets their much due recognition at #AbSciCon2019 #AbSciCon2019. Great job everyone! pic.twitter.com/DMZvdUBbUj

— L. Miché Aaron (@Astrenome) June 27, 2019

We have a cake in honor of the New Frontiers announcement. @PlanetDr

Design added post 4pm, courtesy @JessicaSpake pic.twitter.com/0YHjdJLcoi

— Sarah E Moran (@Of_FallingStars) June 27, 2019

Saturn and I have a lot to celebrate tonight #dragonfly #Titan #SPACETHO pic.twitter.com/uKiOIAbDPQ

— Erin Ross (@ErinEARoss) June 28, 2019

Dr Zibi Turtle (⁦@Eretmochelys⁩) gets a rockstar welcome at the ⁦@JHUAPL⁩ celebration for the #Dragonfly selection. Her joy as she thanked the lab and the team for their support and hard work is contagious! #NotCryingYouAre pic.twitter.com/8jLj3lu4d8

— Dr. Angela Stickle (@schmemela) June 28, 2019

 

And the happiness continued the next day:

Bought myself a happy Dragonfly day present pic.twitter.com/Bigiq7wUS9

— Dr./Prof. Sarah Hörst (@PlanetDr) June 28, 2019

So excited this morning remembering all over again that we are going back to Titan! #Dragonfly pic.twitter.com/3Z4OIxa5gL

— Ellen Stofan (@EllenStofan) June 28, 2019

 

The wait to get back to Titan has been long:

YAY #DRAGONFLY! I’m so excited! (Sketch from DPS/EPSC ‘17.) pic.twitter.com/o6ae3EWqqc

— James Tuttle Keane (@jtuttlekeane) June 27, 2019

This is the final paragraph of my PhD dissertation (from 2011). Just give it a little time 2011 Sarah, a mission beyond your wildest dreams is coming and they’ll let you help.pic.twitter.com/yndG4ONqRB

— Dr./Prof. Sarah Hörst (@PlanetDr) June 28, 2019

 

The wait for Dragonfly data will be even longer:

When you have to wait until 2034 to see some dank scientific imagery and data from another planet’s moon. #Dragonfly #AbSciCon2019 #AbSciCon19 pic.twitter.com/XmyKwZN1yv

— L. Miché Aaron (@Astrenome) June 27, 2019

 

But one thing’s now for certain: We’re going back to Titan!

Yes. Yes we are. pic.twitter.com/lG9k8eL9jR

— Dr./Prof. Sarah Hörst (@PlanetDr) June 27, 2019

—Kimberly M. S. Cartier (@AstroKimCartier), Staff Writer

Contrails’ Climate Impact Could Triple by 2050

Fri, 06/28/2019 - 15:38

Global heat trapped by high-altitude airplane contrails could more than triple by 2050, according to a study published yesterday in Atmospheric Chemistry and Physics. The rapid rise in contrail cirrus clouds is due in large part to an expected rise in air traffic in the coming decades, the researchers said.

“Contrail cirrus’ main impact is that of warming the higher atmosphere at air traffic levels and changing natural cloudiness,” coauthor Ulrike Burkhardt, an atmospheric scientist at the German Aerospace Center (DLR) in Oberpfaffenhofen, said in a statement.

It’s clear that the contrail cirrus clouds will warm the atmosphere, according to lead author Lisa Bock, an atmospheric scientist at DLR. However, “there are still some uncertainties regarding the overall climate impact of contrail cirrus and in particular their impact on surface temperatures,” she said.

Simulating Cirri

When heat from the Sun strikes Earth’s surface, Earth bounces some of it back toward space. But some of the radiation that Earth tries to send away is forced back to the surface by clouds. This process is a normal part of Earth’s energy balance and part of what makes the planet warm enough to live on.

Airplanes, however, are messing up that balance. Soot in airplane exhaust seeds icy clouds, contrail cirri, that crisscross the sky at altitudes greater than 6 kilometers. In 2005, air traffic contributed about 5% to the global amount of anthropogenic radiative forcing, not from its carbon dioxide (CO2) emissions but from the contrails left behind.

Using climate models, Bock and Burkhardt calculated the global amount of radiative forcing from contrail cirrus clouds under current climate conditions and a predicted 2050 climate. They included the expected level of air traffic in 2050 and calculated values for current and improved emissions standards.

The team found that global radiative forcing from contrail cirrus clouds will increase threefold by 2050. This increase was mostly due to the rise in air traffic and not the different climate conditions in the future. Airspace with the densest air traffic, including southeast Asia, western Europe, and the eastern United States, will be the most heavily affected.

These maps show simulated global radiative forcing levels from contrail cirrus clouds from (a) current climate and current airplane traffic, (b) current climate and expected 2050 airplane traffic, (c) predicted 2050 climate and expected 2050 airplane traffic, and (d) predicted 2050 climate, expected 2050 airplane traffic, and improved fuel efficiency and emission standards. Credit: Bock and Burkhardt, 2019, https://doi.org/10.5194/acp-19-8163-2019, CC BY 4.0 Corralling Contrails

Contrails have warmed the atmosphere more than all of the CO2 released by airplanes since the birth of flight. This contribution cannot be ignored by climate mitigation policies, Bock said.

“It is important to recognize the significant impact of non-CO2 emissions, such as contrail cirrus, on climate and to take those effects into consideration when setting up emission trading systems or schemes,” Bock said.

In the face of an inevitable rise in airplane traffic, the best way to minimize the impact of airplane contrails on the climate is to cut airplane soot emissions by at least 50%, the researchers found. Switching to more efficient fuels would also help to a lesser degree. These measures would reduce a small amount (15%) of the heat trapped by contrail cirrus clouds, they concluded.

Adopting stricter fuel standards “would enable international aviation to effectively support measures to achieve the Paris climate goals,” Burkhardt said.

—Kimberly M. S. Cartier (@AstroKimCartier), Staff Writer

Latest Climate Model Points to Hotter Earth

Fri, 06/28/2019 - 11:55

Andrew Gettelman knew that something was missing, and he thought that he could find it when, in January 2018, he took off in a plane from Hobart, Australia, and flew into low-lying clouds hovering over the Southern Ocean.

Gettelman is a cloud physicist and senior scientist who works at the National Center for Atmospheric Research (NCAR) in Boulder, Colo., and he is part of the legions of researchers who help design and build one of the world’s leading computer models that simulates the planet’s climate: the Community Earth System Model (CESM).

Last year, the latest version of CESM, CESM2, debuted. Results from this new version’s simulations point toward a much hotter future climate—driven by humans continuing to burn fossil fuels and pump greenhouse gases into the atmosphere—than any previous version of CESM.

The jump comes after simulations in which researchers doubled the concentration of carbon dioxide in the atmosphere, starting with levels that existed before the dawn of the Industrial Revolution. (Those concentrations were about 280 parts per million. Today, levels are about 415 parts per million.)

Results from the same simulation from older versions of CESM were 2.9°C of warming in 2006, then 3.2°C in 2009, and 4.1°C in 2012.

Now the projected warming is 5.3°C. The planet has already warmed by 0.7°C to 0.9°C.

Gokhan Danabasoglu presents results from CESM2 simulations at the annual CESM workshop in Boulder, Colo. Credit: Lucas Joel

“We are not alone,” said NCAR ocean and climate modeler Gokhan Danabasoglu during a presentation about the results last week in Boulder at NCAR’s annual CESM workshop.

Other climate models constructed by other research groups, Danabasoglu explained, are finding similarly high temperature values. They include the Energy Exascale Earth System Model (E3SM), built by the U.S. Department of Energy, which reported a value of 5.3°C, and the Canadian Earth System Model (CanESM), which reports a value of 5.7°C.

Supercooled Liquid Clouds

One of the reasons for the jump likely has to do with how clouds behave in CESM2. That is why Gettelman was on a plane darting over the Southern Ocean. “It’s pretty interesting flying at a high Mach number 300 feet [91 meters] over the Southern Ocean when you’ve been briefed on where the survival suits are and there’s nothing out there for a thousand miles [1,600 kilometers] in any direction,” he said.

“Even if we take mitigation steps and we’re not on a high-emissions trajectory, it still means we’ll get more warming.”Gettelman did not fly through a cloud made mostly of vapor or of ice. It was a supercooled liquid cloud, one in which vapor condenses into water droplets that although they exist at subzero temperatures, do not freeze. Clouds like this are brighter than other clouds, and they reflect sunlight back out into space, helping to keep the planet cool. But as the planet warms, these clouds seem to be getting thinner, Gettelman explained, which erodes their cooling effect.

Gettelman and his colleagues added the missing knowledge about supercooled liquid clouds to CESM2, along with other changes to the models’ cloud physics, in an effort to make the clouds in the model behave more like clouds do in the real world.

Results from models like CESM2 are what the United Nation’s Intergovernmental Panel on Climate Change references in its reports on the state of climate change. It publishes data on just how bad climate change will get—including forecasts on how events like wildfires, hurricanes, and droughts will become more commonplace—depending on the extent to which humans manage to cut their fuel emissions.

“Even if we take mitigation steps and we’re not on a high-emissions trajectory, it still means we’ll get more warming,” Gettelman said.

It’s too early, though, to say whether or not the 5.3°C jump is set in stone, according to Ben Sanderson, a climate scientist at the European Center for Advanced Research and Training for Computational Science in Toulouse, France, and an affiliate scientist with NCAR who is not directly involved in CESM’s development. “It’s fundamentally hard to constrain because there’s no direct way to observe it,” he said.“It potentially means larger climate impacts if this is correct.”

As this is a brand-new result, Sanderson added, there may be other model forces behind it that researchers may yet unearth.

Regardless, it does not bode well that other modeling groups are getting similar results.

“The fact that other people with independent modeling decisions and independent modeling pathways totally from us ended up at the same place as they got their models more realistic, that’s what bothers us,” Gettelman said. “It potentially means larger climate impacts if this is correct.”

—Lucas Joel, Freelance Journalist

Rock On with a Group That Makes Music from Geophysical Data

Fri, 06/28/2019 - 11:54

A musician-scientist team is giving a whole new meaning to the term “rock music.”

Geophysicist Antonio Menghini and musician Stefano Pontani have created a method of transforming geophysical data into jazzy, ephemeral refrains as part of their EMusic project. The group teams up with musicians on saxophone, guitar, and other instruments to bring geophysical soundscapes to life at conferences and outdoor venues across Europe.

Sonification projects are part of a growing interest by scientists to enhance and clarify scientific information. A four-part string quartet performance about warming temperatures from climate change and an effort at Columbia’s Lamont-Doherty Earth Observatory to convert seismic wave data from earthquakes into sounds are just two examples of scientists turning to music to communicate their research.

EMusic aims at helping people understand a particular landscape’s geology through sound and live performances. They transform electromagnetic measurements of the subsurface into musical notes, an effect that Menghini said creates a “natural soundtrack of the landscape.” The data come from measurements that Menghini and his team have taken on the ground and by air, and they show the resistivity of a material, revealing the composition of layers and structural features like dikes and faults. They then perform this music to live audiences, in some cases at the exact location where the data were taken.

Eos selected a few of EMusic’s videos to dive into Earth’s soundscape. Sit back, relax, and listen to the layers of Earth pass you by.

How to Listen to EMusic

First, a primer on how EMusic chooses its notes: Each note from the geophysical data represents the resistivity of the material below. The EMusic team then normalizes the readings and applies a routine to fit them within a musical scale. This video shows how the electromagnetic measurements are taken and features the earthly vibrations of granite, greenstone, aquifer-regolith, and gold.

What Lies Beneath an Ancient Theater?

At a concert performed in the ruins of an ancient Roman theater of Ferentium (modern Ferento) in central Italy in 2017, EMusic plays the eerie tones of its electromagnetic readings from below the theater for the first half of the video. At around 7 minutes into the piece, a saxophone joins the refrain. Menghini calls this a “natural jam session, where the Earth is the band leader.”

The Beat of the Diatomites

In the third installment of the five-part Ferentium concert, this composition reveals the sounds of a layer of diatomite, a porous sedimentary rock packed with skeletal remains, that sits 30 meters below the surface. Menghini writes that listeners can ponder the ancient setting that gave rise to this layer, characterized by “quiet lagoons and swamps, where the African fauna (elephants, lions, tigers) lived in the past.”

Sounds from Around the World

In an excerpt from a concert at Tuscia University in Viterbo, Italy, in 2018, electromagnetic data blend with saxophone, electric guitar, and electronics to give a tour of geologic sites in Canada, Russia, Sierra Leone, and Italy.

Flying Through an African Greenstone Belt

Finally, in one tune from airborne data taken in Sierra Leone, the viewer is launched into a rendering of the landscape. Fly along as we travel deeper into Earth and musical notes ring out as the composition changes. Colors of strata underground represent the resistivity of the material, with warm tones showing less resistivity and cool tones showing more resistive layers.

Jam Session with Mount Vesuvius

Where will EMusic go next? This September, EMusic is slated to perform from the rim of Mount Vesuvius, the volcano that once destroyed the Roman cities of Pompeii and Herculaneum. The concert will begin with the scientists first collecting electromagnetic data, which Menghini will see for the first time along with the audience. After the band converts the data into notes, the audience will hear an auditory tour of what’s below their feet, with jazz musicians mingling tones with Earth’s geologic melody.

—Jenessa Duncombe (@jrdscience), News Writing and Production Fellow

Louise H. Kellogg (1959–2019)

Thu, 06/27/2019 - 13:45

With the premature death of Louise Kellogg, the geoscience community lost a thoughtful and influential leader.

After a childhood spent in Pennsylvania and Maryland, Louise obtained her Ph.D. in geological sciences from Cornell University, where she was advised by Don Turcotte. After a 2-year postdoc at the California Institute of Technology (Caltech), where she worked with Jerry Wasserburg, Louise joined the Geology Department at the University of California (UC), Davis, where she remained for the rest of her life.

At the time of her passing and since 1998, Louise held the title of professor of Earth and planetary Sciences at UC Davis.

A Pioneer in Modeling Mixing in the Mantle

While pursuing her Ph.D. at Cornell, Louise pioneered the quantification of mixing and stirring of subducted lithosphere into Earth’s mantle through chaotic flow to address the origin and scales of long-lived geochemical heterogeneity.

During her postdoctoral work at Caltech, she developed a simple and insightful box model for helium outgassing throughout Earth’s history to explain excess 3He in hot spot volcanoes.

This multidisciplinary interest persisted throughout Louise’s career, sustained by collaborations with, among others, Scott King on the nature and evolution of the seismologically observed D″ layer at the base of the mantle and the modeling of mantle plumes.

Perhaps Louise’s most influential idea is the model of compositional stratification developed with collaborators Brad Hager and Rob van der Hilst.Perhaps Louise’s most influential contribution is the model of compositional stratification developed with collaborators Brad Hager and Rob van der Hilst. In this model, she proposed the presence of a stable, compositionally distinct, but hot, layer of variable thickness in the deep mantle to explain the difference in isotopic compositions of mid-ocean ridge and oceanic island basalts, as well as the heat flow budget of Earth. This original idea continues to inspire scores of geodynamical, seismological, and mineral physics studies.

Notably, the illustrative cartoon accompanying the 1999 paper in Science developed a life of its own and is now part of a classical collection of cartoons presenting contrasted views of mantle circulation. As Louise would point out, “sometimes other scientists share it with me, not knowing its origin in my own paper.”

In later work, Louise harnessed the power of higher-resolution numerical simulations to further investigate thermochemical convection in the mantle and, in particular, the role of initial conditions and viscosity structure for the preservation of heterogeneity through geologic time.

Later Contributions

As we look back through Louise’s body of research work, we are struck by the profound insights expressed in her papers: Although the science progresses over time through the collective contributions of many researchers, her ideas are still relevant to key questions and debates in global solid Earth geosciences.

In her later work, Louise became interested in combining geodetic and seismic data with nonlinear system simulations to investigate strike-slip fault interactions and sequences of major earthquakes in California and elsewhere.

Louise also devoted some of her considerable energy to establishing the W. M. Keck Center for Active Visualization in the Earth Sciences (KeckCAVES), the 3-D scientific immersive visualization center at Davis, with initial support from the W. M. Keck Foundation and subsequent support from the National Science Foundation (NSF) and other agencies. She was instrumental in putting KeckCAVES to use at the interface between geosciences and computer sciences: visualizing flow in the ancient oceans, modeling Earth’s deep interior, interpreting lidar data, and tracking carbon from volcanic plumes to the depths of the mantle. KeckCAVES continues to play an important role in outreach to the public, with projects such as the original Augmented Reality Sandbox.

Louise did not live to see the acceptance for publication of her last manuscript about scalable, parallel visualization of geodynamo simulation data, on which she eagerly worked in collaboration with Yangguang Liao and Hiroaki Matsui from UC Davis.

Exceptional Service Record to the Geoscience Community

Louise left an exceptionally distinguished record of service to the geoscience community.Louise left an exceptionally distinguished record of service to the geoscience community, most recently as the director of the Computational Infrastructure for Geodynamics (CIG), a consortium of more than 70 affiliate institutions funded by NSF in support of the development of codes for numerical simulations in solid Earth geodynamics. CIG flourished under her leadership and has become an essential resource for the geophysical community.

Louise also led the Deep Carbon Observatory Modeling and Visualization Forum, enabling new understanding of carbon pathways in the deep mantle.

She also played an important role in the establishment and success of the Cooperative Institute for Dynamic Earth Research (CIDER), providing, from its very beginning in 2003, inspiration and leadership as a founding member, lecturer, and member of the steering and executive committees. It was Louise’s idea, in 2009, to change the “D” in CIDER from “Deep” to “Dynamic” when the focus of CIDER expanded from the very deep Earth to encompass global research questions reaching the surface and beyond.

Louise had a unique talent for articulating and extracting the essence of the often-disordered suggestions and ideas that arise in committee meetings, effectively helping move forward community initiatives. She knew how to listen and channel discussions and turn them into action items.

Louise was often solicited to participate in and chair various panels and committees at the national level for NSF, the National Research Council, and AGU. These appointments and roles include the NSF Advisory Committee for the Geosciences Directorate, which she chaired from 2010 to 2013, and the U.S. National Academies’ Committee on Seismology and Geodynamics, which she chaired from 2007 to 2009. As chair of the NSF workshop on Frontiers of Mathematics in Geosciences (2001) she helped establish an important cross-disciplinary NSF program.

Louise shaped the department through her mentoring of young faculty, postdocs, and students.As chair of the Department of Geology (2000–2008) and later interim chair (2013–2014, 2016–2017) of the Department of Earth and Planetary Sciences at UC Davis, Louise shaped the department through her mentoring of young faculty, postdocs, and students. She achieved this by listening to, and hearing, many points of view and seeing a path to bring people to a common vision and through her never-ending joy in sharing the awe of geoscience with everyone, from students in a general education Earth hazards class to visitors at the campus “Picnic Day” to administrators from across campus.

Louise was a champion for equity and diversity efforts across campus, understanding that small changes can have big impacts. As chair, she supported her department’s efforts to build a diverse faculty, increasing the percentage of women to over 30%. She donated a prize she won for promoting diversity to establish “Tuesday Tea” as a time for all members of the department to come together.

Honors

Louise’s scientific achievements were recognized, in particular, by a Presidential Faculty Fellowship (awarded to her by G. H. W. Bush, 1992–1997) and fellowships in AGU (2010), the American Association for the Advancement of Science (2012), and the American Academy of Arts and Sciences (2013).

Louise died prematurely of cancer at 59, sending waves of sorrow and shock across a vast geoscience community of collaborators and friends whom she impacted through her vision and energy, including the authors of this tribute. Barbara Romanowicz arrived in northern California at the same time as Louise and worked for 20 years with Louise’s husband, Doug Neuhauser. She enjoyed a special relationship with Louise, which culminated in their shared enthusiasm for the establishment and development of CIDER. Magali Billen is one of those lucky faculty to have been mentored through their early years by Louise and to have shared in her friendship ever since.

Memories of Louise can be shared on the following web page: https://geology.ucdavis.edu/people/inmemoriam/kellogg/memories.

—Barbara Romanowicz (barbara@seismo.berkeley.edu), University of California, Berkeley; also at College de France, Paris; and Magali Billen, University of California, Davis

Age and Speed Matter in the Formation of New Oceanic Crust

Thu, 06/27/2019 - 13:44

New oceanic crust is continuously being formed as magma upwells at mid-ocean ridges. The characteristics of oceanic crust hold clues about its age and the environment in which it formed. A recent article in Reviews of Geophysics synthesized data on oceanic crust from many different studies globally, comparing age and spreading rate. Here, one of the authors gives an overview of what we know about oceanic crust and suggests where additional research is needed.

What are the main characteristics of oceanic crust?

The first marine investigations in the mid-twentieth century discovered that oceanic crust had a distinct layered structure with “pillow lavas” at the top, “sheeted dikes” in the middle, and “gabbros” at the bottom overlying mantle rocks.

The three main layers of oceanic crust: (left to right) pillow lavas, sheeted dikes, gabbro. Credit: Kathy Gillis

How is it possible to study oceanic crust?

Some oceanic crust is easy to study because it is now exposed on land; this is known as an “ophiolite”. This crust was formed many millions of years ago and has subsequently been moved by tectonic forces and eventually ended up above sea level where researchers can examine it in detail.

On the other hand, a vast amount of oceanic crust remains underwater. At fracture zones it is possible to see exposures of oceanic crust, otherwise, we can find out what’s below by drilling into the crust and extracting cores. However, to date, there have only been a few isolated drill holes, and these have only penetrated part way into the oceanic crust.

Thus, much of our knowledge about the structure and composition of oceanic crust and the processes of its formation comes from ophiolites.

How else can we learn about the characteristics of oceanic crust?

Seismic techniques are another way to ‘look’ into the rock below. Seismic waves are sent down into the crust and a signal bounces back. This is used to calculate the “seismic velocity”, which offers clues about the physical properties of rock at different depths, such as different layers and their composition.

A two‐dimensional velocity model of the crust and upper mantle of part of the Juan de Fuca plate. Credit: Horning et al. [2016], Figure 4aSince the earliest studies, the challenge for scientists has been to correlate the layers seen in seismic profiles with known physical rock characteristics observed from ophiolites and drilling so that layer boundaries, such as between dikes and gabbros, can be mapped throughout the ocean basins.

How does new crust vary depending on the rate of spreading?

At fast-spreading ridges magma supply is relatively constant and produces a uniform crust, while at slow-spreading ridges magma supply is more ephemeral and produces a heterogeneous crust. However, rather surprisingly, the structure revealed by seismic imaging is very similar for different spreading rates.

The goal of our new study was to tease out differences related to age and spreading rate by synthesizing data from many studies throughout different ocean basins. We found that the seismic boundary between upper and lower crust is thinner for fast-spreading crust than for slow-spreading crust. The seismic boundary corresponds to the lithologic boundary between dikes and gabbros for fast-spreading crust but marks a change in porosity within the dikes (likely related to faulting) for slow-spreading crust.

What other factors influence the characteristics of the crust?

There is a significant correlation between seismic velocities at the top of the crust and the thickness of the overlying sediment. The thick sediment likely collapses large-scale features such as lava tubes and fractures. Many thick sediment regions are located near continental margins, such as the East Coast of the United States.

Age is also a key influence. Seismic velocities at the top of the crust increase rapidly for the first approximately 10 million years then continue to evolve to the oldest ages in our study (170 million years). We think these changes are related to hydrothermal circulation in the ocean crust, which is very active near the ridge crest but must continue even into older crust.

Overall, we find that our results group into four categories: young, slow-spreading crust; young, fast-spreading crust; old, slow-spreading crust; and old, fast-spreading crust.

Summary of lithologic interpretation of velocity-depth function for the four subgroups. Credit: Christeson et al. [2019], Figure 13For example, young, slow-spreading crust has the lowest velocities at the top of the lower crust which we think is related to deep faults. In contrast, the average crustal thickness is 6.15 kilometers and is similar for crust formed at different spreading rates.

Your paper includes a Jupyter notebook as Supporting Information. How does this benefit other scientists?

Users can use a Jupyter notebook to explore all aspects of the ocean crust dataset. Credit: Gail Christeson

A Jupyter notebook is an open-source web application that allows scientists to share and document analysis and visualizations.

Our notebook is written in Python, which is an open source software that is widely available and runs on multiple platforms. We hope that people can use the notebook to analyze the data set in different ways that will lead to discoveries beyond our initial analysis.

Users should also be able to modify the notebook to compare measurements from their own seismic profiles with the compilation values at a specific range of ages and spreading rates. We expect that Jupyter notebooks will become more common since the Python programming language is rapidly growing in popularity.

What are some of the unresolved questions where additional research, data or modeling is needed?

There are only a few deep scientific drill holes in oceanic crust where rock layers can be directly compared with seismic velocities. It’s always a bit scary when you widely extrapolate results based on only a few data points, so additional deep oceanic crust drill holes are definitely desirable.

—Gail Christeson (email: gail@ig.utexas.edu), University of Texas Institute for Geophysics

Honoring Volcanologist David Johnston as a Hero and a Human

Thu, 06/27/2019 - 13:41

Just over 39 years ago, Mount St. Helens in Washington erupted and claimed the lives of 57 people. One of those lost was Dr. David A. Johnston.

Johnston was the first volcanologist on the mountain’s flank when it stirred after more than 100 years of quiet. With a Ph.D. just 2 years old, Johnston was studying volcanic gas emissions with the U.S. Geological Survey to understand what part those emissions play before and during an eruption.

“He would call home and say, ‘I just can’t believe they’re paying me to do this!’”“There are quotes from his parents, that he would call home and say, ‘I just can’t believe they’re paying me to do this!’” Melanie Holmes told Eos.

Holmes is the author of a new biography of Johnston titled A Hero on Mount St. Helens: The Life and Legacy of David A. Johnston. “His dream was absolutely to have a job with the U.S. Geological Survey, and there he was. He was doing what he loved.”

Johnston was at the Coldwater II observation post just outside the red zone when the volcano erupted on 18 May 1980. The night before, he had taken over the post from his field assistant, Harry Glicken. Glicken would continue studying active volcanoes until he lost his life 11 years later at Mount Unzen in Japan.

Johnston sent Glicken and two others away to safety that night, so it was Johnston who announced Mount St. Helens’s eruption to the world—“Vancouver! Vancouver! This is it!”—moments before his death.

“If I had to guess, I would say he enjoyed it so much because it was a puzzle,” Holmes said. “And who among us doesn’t love putting together the pieces of a puzzle that we’re just really fascinated with? For me it was the puzzle of a man and it was the puzzle of a mountain.”

Holmes spoke with Eos about the major influences in Johnston’s life and the mark he left on volcanology and the world. Our conversation has been edited for clarity, grammar, and length.

Eos: Looking back at the entirety of David Johnston’s life and the legacy he left behind, what do you feel are some of the most defining points in his life?

David Johnston uses a spectrometer to measure the sulfur dioxide content of gases ejected from Mount St. Helens on 4 April 1980. Credit: USGS

Holmes: I find it fascinating that he was among only two U.S. Geological Survey scientists who were looking into gas emissions as a way of determining what’s going on in a volcano and looking at precursory signals. It was him and Tom Casadevall, and they were both hired in 1978. Tom Casadevall was assigned to the Hawaiian Volcano Observatory to start a gas lab there. And David was working out of Menlo Park, Calif., but his area included the Cascades [and Mount St. Helens]. He was on his way to Alaska, and he would have expanded gas research there on Alaskan volcanoes. I find that fascinating, that he was one of only two volcanologists with the Survey who were looking into this. It feels very much like he was a pioneer.

And the Survey has said, since March of 1980 when Mount St. Helens became active again, that [evaluating] volcanic gas emissions has become an integral part of the Survey’s monitoring programs.David always referred to “a link in the chain. A link in the chain.”

David always referred to “a link in the chain. A link in the chain.” He made that statement after he defended his dissertation on Augustine Volcano in Alaska. He felt like his work at Augustine was that link in the chain.

And in November of 1979, he did a geothermal study of the Azores, and he met with top officials there. Azorean officials ordered more studies based on what David suggested. He helped them map out their geothermal possibilities, places where they could create or expand. After he visited, Azoreans installed their first pilot plant, and their geothermal resources increased from there. And that’s very important. There is a statement in a letter of condolence that was sent to his parents by the Azorean regional director of energy [Deodato Sousa], who wrote to his parents and said, “David Johnston’s name will remain attached to the new era of energy in the Azores.”

Eos: Until I read the book, I didn’t fully realize how many programs and grants and fellowships and observatories and all sorts of things have been dedicated to Johnston and how many different aspects of this field he has inspired or shaped or touched.

David Johnston climbs down into a crater near the summit of Mount St. Helens on 30 April 1980 to collect samples from an ephemeral pond at the bottom. Credit: Rick Hoblitt, via USGS

Holmes: A seed for the book is the idea of a hero among heroes. So the title of the book [A Hero on Mount St. Helens], it definitely doesn’t have the word “the,” and it doesn’t even just say “hero.” It has to be “a hero” because there are so many heroes in his generation, in his immediate sphere, and all the places that the book touches upon.

We say that David touched the lives of so many people. It was the U.S. Geological Survey that enabled him to go to the Azores. It was whatever grad student stipend that allowed him to go to Augustine. There are all these intertwined heroic efforts that drove the science forward and that allowed someone like David to do what he was doing.

At Mount St. Helens, so many people felt like they should’ve known, right? Well, gas emissions were a part of that. [Experts] were expecting to see a higher level of gas emissions. So David insisted on getting to the volcano when he could. He went down into the summit crater—they called it the ephemeral ponds—to get an actual sample of that water. Twenty people could say that was reckless, but that was his way of saying, “Look, gas emission is an important part of the puzzle.” He landed at the summit crater rim on May 17, the day before he died. And I think he was frustrated that he wasn’t seeing the levels that they were expecting to see. Of course, we know now that the mountain was waterlogged, and that’s why. To respect those who went through so much and lost so much, we [must] always respect how young the science was at that time.

If we in Chicago or Cleveland or Detroit don’t understand why volcanoes research is important, then there’s always that possibility that down the road we’ll want those budgets slashed. That cannot happen.Mount St. Helens is the most studied volcano in history.…There’s no getting around how much the eruption of Mount St. Helens contributed to science and therefore to the potential for safety for people of future generations—the people with volcanoes in their backyards.

As Midwesterners, we do not talk about volcanoes over dinner. Yet it is an important science that everyone in the United States must acknowledge is important and support its practitioners and make sure that budgets are there so that they can do their work. If we in Chicago or Cleveland or Detroit don’t understand why volcanoes research is important, then there’s always that possibility that down the road we’ll want those budgets slashed. That cannot happen.

Eos: Having grown up in the Chicago suburbs myself, I was raised with stories of the Oak Lawn tornado that struck Johnston’s hometown while he was in high school. How did living through that natural disaster and narrowly escaping the eruption of Augustine Volcano affect Johnston’s life and shape the direction of his career?

Holmes: David was only 17…when he went out into the streets of Oak Lawn with his dad taking pictures of the devastation. There was a girl from his high school that was killed.…So it all hit very close to home. His seeing the lack of being able to protect the innocent must’ve felt really personal for him.

He was empowered, I think, because he knew he could protect someone.The people who’ve gone on after Mount St. Helens have all taken [a sense of responsibility] with them. And I cite some of those examples in the book, such as Carolyn Driedger and Mindy Brugman, who were on the ridge talking with David the night before and he sent them away. [Driedger] went on to work at the David A. Johnston Cascades Volcano Observatory, and she’s still there. It’s really important to someone who goes through something like that, where it just feels so personal and they think, they feel that they can do something to protect the innocent.

I think the Oak Lawn tornado was a very big part of it [for Johnston]. You could see how it fueled David. Here’s this person who’s been fainting from public speaking since eighth grade, and now he’s surrounded by reporters. There are microphones and cameras poised in front of his face, and it must’ve been really daunting for him. But he was empowered, I think, because he knew he could protect someone.

Eos: You acknowledge some of the personal struggles that Johnston faced in his younger years and during the start of his professional career: low self-esteem, bullying, anxiety, fainting. Why did you feel that those parts of his life and his experience, and his growth from them, were so important to go into?

David Johnston relaxes at the Coldwater II observation post on 17 May 1980. Credit: Harry Glicken, via USGS

Holmes: We look at him as a hero, but he was also human.…It goes back to the idea of can we see ourselves as a hero? The quote from Brad Meltzer in the epigraph of the introduction captures it: “We are all ordinary. We are all spectacular. We are all shy. We are all bold. We’re all heroes. We are all helpless. It just depends on the day.” Can we see ourselves in the story of someone that we revere so much?

Eos: What do you feel this holistic view of Johnston’s life teaches us about the scientific endeavor as a human experience?

Holmes: To my knowledge, this is the first biography of a volcanologist. It is a career path that is not well understood. One of the people who reviewed the book said, “It would’ve been really easy to lionize David’s life.” When we think about Einstein or Stephen Hawking, do we think about how they got to the point where they’ve made great discoveries? What came before that? Did they get all straight A’s?…Telling the story of David in boyhood and teen years, looking at how someone gets to the point where people look at them as, quote unquote, a hero—it seems important to look at the building of the man, if you will. And he got D’s in high school in math and algebra. So I’m looking at him as a human, and I think that makes him more approachable.

It also helps people to look and say to themselves, “I could do that.” And we need more people who say to themselves, “You know, I might’ve pulled D’s in algebra, but I can still do something really important with science. I can climb this mountain. I can conquer this challenge.”

—Kimberly M. S. Cartier (@AstroKimCartier), Staff Writer

Surveys Say Climate Change Is a Top Election Issue for Democrats

Wed, 06/26/2019 - 18:01

With Democratic candidates for president holding their first debates this week in Miami, Fla., two new related surveys show that climate change and clean energy are top-tier issues for Democratic voters in 2020.

“We believe that the debates in Miami and the following debates in other places offer candidates a critical opportunity to discuss their plans for climate action,” said Peter Maysmith, senior vice president of campaigns for the League of Conservation Voters (LCV), at a 25 June briefing about the surveys. “No candidate for president should be taking the debate stage, especially in a frontline community like Miami, without discussing how he or she will address this crisis on day one and really throughout every day of their presidency.”

A majority of surveyed general election voters believe that climate change is a crisis or a very serious problem and that Democrats have a clear advantage over President Donald Trump and Republicans.The surveys were conducted jointly in June by Normington Petts and Hart Research Associates for LCV and the progressive Center for American Progress Action Fund (CAP Action Fund). The surveys polled 1,000 likely 2020 Democratic primary voters and caucus-goers and 1,201 registered voters in 14 battleground states. Those battleground states, which Trump narrowly won in the 2016 election, include Florida, Michigan, and Wisconsin.

A majority of surveyed general election voters believe that climate change is a crisis or a very serious problem and that Democrats have a clear advantage over President Donald Trump and Republicans on climate change and the environment.

Fifty-five percent of the surveyed general election voters consider climate change a crisis or a very serious problem, and another 24% consider climate change a somewhat serious problem.

Most of the surveyed general election voters trust Democrats over Trump in addressing climate change, with 87% of Democrats, 54% of Independents, and 22% of Republicans trusting Democrats, and with fairly similar numbers trusting Democrats to move the country to clean energy sources.

Climate change and a clean energy economy rank as the fifth most important overall issue among Democratic primary voters, according to the surveys, with 71% of voters rating it that way, on par with “racism/racial justice” and not far below other issues, including “woman’s right to choose,” “stronger gun policies,” “universal health care,” and “wages/income for working families.”

“Climate change and moving to a clean energy economy is a top-tier issue for Democratic primary voters. They are going to demand to hear from Democratic candidates on this topic, they are going to insist that Democratic candidates have clear plans of how to move to a clean energy economy, and they are going to demand that those plans also follow the established science where climate change is concerned,” said Jill Normington, a partner with Normington Petts.

Strong Support for Differing Approaches to Climate Change

The surveys show that 79% of Democratic primary voters want a climate plan that is realistic and can actually be turned into law. They also consider it important that a plan meet other criteria, including transforming the U.S. economy with scope, scale, and speed to avoid the worst effects of climate change; meeting scientific recommendations to limit global warming to 1.5°C; creating millions of jobs; and ensuring that workers in the fossil fuel industry have meaningful work opportunities in clean energy. In addition, Democratic primary voters said that the plan should attract bipartisan support in Congress, prioritize pollution reductions first in communities with the worst air quality, and help a Democratic candidate defeat Trump.

Democratic primary voters voiced strong support in the surveys for several approaches that candidates might have for dealing with climate change and clean energy, including addressing climate change in time to avoid the worst effects (85% support), moving the country to 100% clean energy by 2030 or 2050 (83%), and moving from oil and gas to renewable energy (81%). The surveys found 56% favorability for the Green New Deal among Democratic primary voters but also found that 28% do not know what it is.

“Democratic primary voters are not insistent that there is only one approach” to dealing with climate change and moving toward a clean energy economy, Normington said. “It’s more about the goals of what a move to a clean energy economy will accomplish.”

“When President Trump and other Republican elected officials deny the very reality of climate change and also deny the need to address it, they are putting themselves very much at odds with the majority of general election voters.”Normington added that “it’s very clear that support for the Green New Deal is not a litmus test issue for the Democratic primary and caucus-going electorate as a whole.”

The surveys also show that 48% of Democratic primary voters already are feeling the effects of climate change and that another 42% are not yet feeling the effects but worry about climate change.

“The good news is that there has been a real shift on public concern” about climate change over the past several decades, said Navin Nayak, executive director of the CAP Action Fund. “The unfortunate news is [that] a lot of that concern is being driven by people feeling the real-world impacts in their own daily lives, and that creates a significant political vulnerability for Donald Trump and a real opportunity for Democrats.”

Geoff Garin, president of Hart Research, added about the surveys’ findings, “When President Trump and other Republican elected officials deny the very reality of climate change and also deny the need to address it, they are putting themselves very much at odds with the majority of general election voters.”

—Randy Showstack (@RandyShowstack), Staff Writer

Designing the Global Observing System for Marine Life

Wed, 06/26/2019 - 12:33

A globally coordinated and sustained ocean observing system is urgently needed to systematically assess the status of the ocean’s biodiversity and ecosystems. Tracking how ocean life is responding to increased human use and climate change will enable the global community to effectively predict, mitigate, and manage our ocean. Monitoring scientifically and societally relevant biological essential ocean variables (EOVs) is expected to address these scientific issues and to support policy and management decisions.

More than 20 international, multidisciplinary experts met to design an observing system for these biological EOVs. Their tasks were to identify the existing monitoring backbone for each EOV, identify the extensions needed for these backbones for the next 10 years, and define the attributes of biological observing networks within a global system.

The global distribution of records on marine species occurrence as contained in the Ocean Biogeographic Information System shows that most observations take place in coastal areas and close to developed nations. Each grid square is 70,000 square kilometers. Credit: OBIS, 2019

In addition, participants were asked to identify and prioritize implementation activities to ensure that products support monitoring progress against the 2050 Vision for Biodiversity from the Convention on Biological Diversity and the United Nations’ (UN) 2030 Agenda for Sustainable Development and contribute to the UN Decade of Ocean Science for Sustainable Development.

The monitoring backbone for biological EOVs consists of some well-established data collection networks and/or communities of practice, along with the facilities and platforms used for this purpose.Currently, the monitoring backbone for biological EOVs consists of some well-established data collection networks and/or communities of practice, along with the facilities and platforms used for this purpose. These are quite heterogeneous in terms of capacity, implemented technologies, and data availability across and within variables—specifically across different geographic regions. Some countries conduct regular assessments of all types of organisms, some countries are more limited, and others have no regular assessment framework at all.

For the next decade, technological developments supporting increasingly automated measurements, as well as significant improvements in metadata and data architecture, will be crucial. Just as critical will be management encouraging marine scientists to make their data findable, accessible, interoperable, and reusable (FAIR). Common metadata standards that enable data reuse and interoperability will deliver the potential for scalability and sustainability. Monitoring frequency and spatial scale will depend on the biological EOV and questions to be addressed.

Observing networks will need effective coordination to provide frequency and coverage to address scientific questions relevant to national and regional policy and management priorities. Networks will require standard operating procedures, including technology transfer and in-country support to develop capacity, especially in developing nations.

The most pressing priorities to build a global monitoring system are to establish the leadership and partnerships that will agree on best practices and data architecture, plan their implementation, and communicate them broadly.The most pressing priorities to build a global monitoring system are to establish the leadership and partnerships that will agree on best practices and data architecture, plan their implementation, and communicate them broadly. Addressing these priorities will lead to key technological objectives: cross-platform deployments enabling multivariable measurements, expanded sampling coverage to fill geographic gaps, improved compliance to quality control standards, and operational delivery of data and modeling products, including legacy data.

The development of new technologies and hardware, including increasing automation to bring the marine biological community closer to real-time ocean observing, will also be critical. Together, these improvements will support management decisions and increasingly detailed hypothesis testing.

The agenda, presentations, report, and list of participants are available on our website. We thank the  National Center for Ecological Analysis and Synthesis and Future Earth for their sponsorship and participants for their contributions.

—Patricia Miloslavich (pmilos@usb.ve), Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Australia; also at Departamento de Estudios Ambientales, Universidad Simón Bolívar, Caracas, Venezuela; Nicholas Bax, Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Australia; also at Oceans and Atmosphere, Commonwealth Scientific and Industrial Research Organisation, Hobart, Australia; and Erin Satterthwaite, National Center for Ecological Analysis and Synthesis, Santa Barbara, Calif.; also at Future Earth, Boulder, Colo.

Chemical Patterns May Predict Stars That Host Giant Planets

Tue, 06/25/2019 - 20:37

Does this star have a planet? A new algorithm could help astronomers predict, on the basis of a star’s chemical fingerprint, whether that star will host a giant gaseous exoplanet.

“It’s like Netflix,” Natalie Hinkel, a planetary astrophysicist at the Southwest Research Institute in San Antonio, Texas, told Eos. Netflix “sees that you like goofy comedy, science fiction, and kung fu movies—a variety of different patterns” to predict whether you’ll like a new movie.

Likewise, her team’s machine learning algorithm “will learn which elements are influential in deciding whether or not a star has a planet.” Hinkel is lead author on a paper, accepted for publication in the Astrophysical Journal, that presents this new technique.

Picking Out Patterns

Past studies show that iron-rich stars are more likely to host a giant exoplanet. This new algorithm draws on an extensive database of stellar compositions, the Hypatia Catalog, to test whether that trend holds for groups of elements together.

The team looked at combinations of some of the most common planetary ingredients: light and gaseous volatiles, oxygen-loving lithophiles, iron-loving siderophiles, and iron. The algorithm randomly selects a subset of Hypatia stars known to have giant planets, identifies patterns in their chemical compositions, and decides how important the patterns are when hosting a planet.

In addition to iron, “the elements that ended up being the biggest indicators were carbon, oxygen, and sodium.”By training the program on about 300 planet-hosting stars, the team found that a few elements were consistently good planet predictors. In addition to iron, “the elements that ended up being the biggest indicators were carbon, oxygen, and sodium,” Hinkel said. That makes sense, she said: Gas giant planets need gaseous elements, and planetary cores need iron.

Nickel, to the researchers’ surprise, turned out to be not very important despite forming in a way similar to iron. Sodium, however, was much more important than expected, something they are still trying to explain.

New Stars to Search

The team also applied the predictive patterns to Hypatia stars not yet known to host a planet. By repeating the prediction hundreds of thousands of times for each star, the algorithm calculated the likelihood that a star is a planet host. The team confirmed the algorithm’s accuracy by “hiding” planet hosts among the test stars. The program picked them out about 75% of the time.

All told, the team tested more than 4,200 stars not currently known to have a planet. About 350 of those stars had a more than 90% probability of hosting a giant exoplanet.

“I think that it’d be super useful to be able to know where to look ahead of time,” Hinkel said.

An Important Tool for the Future

“This work is a wonderful example of the power of large data sets such as the Hypatia Catalog, especially when combined with machine learning approaches,” said space scientist Shawn Domagal-Goldman at NASA Goddard Space Flight Center in Greenbelt, Md., who was not involved with this research. A similar approach might also help select stars around which to search for signs of life, he said.

“As exoplanet data continues to build, algorithms like this one are going to be increasingly important tools.”Increasingly, “we are swamped with more data than is feasible to make sense of,” said Steven Desch, an astrophysicist at Arizona State University in Tempe who also did not participate in this study. Techniques like this “draw our attention to patterns we might have missed that are probably clues to how planets are formed.”

“As exoplanet data continues to build, algorithms like this one are going to be increasingly important tools,” Desch said.

—Kimberly M. S. Cartier (@AstroKimCartier), Staff Writer

An Underwater Telescope to Study Sky and Sea

Tue, 06/25/2019 - 12:22

Deep beneath the cool and beautiful waters of the Mediterranean Sea, an international collaboration of particle physicists is building a telescope.

“Most telescopes look at light coming from the sky, and they look upwards to the sky,” Paschal Coyle told Eos. “Our telescope searches for neutrinos and, in fact, looks downwards through the Earth and sees the sky on the other side of the Earth.”

Coyle is an astroparticle physicist at the Marseille Particle Physics Center in France and the physics and software manager for the Cubic Kilometer Neutrino Telescope (KM3NeT). When complete, the array of KM3NeT detectors will turn more than a cubic kilometer of the Mediterranean Sea into a giant net to catch neutrinos in action.

How to Catch a Ghost

Every second of every day, 100 billion neutrinos pass through each square centimeter of your body at nearly the speed of light. These “ghost particles” are born in the hearts of stars, in supernovas, in chemical reactions, and in Earth’s atmosphere.

The best thing about neutrinos is also the worst thing about them, according to Coyle. “They hardly interact with anything,” he said. “They always move in straight lines, and they don’t get absorbed by dust clouds or other objects in the way. With neutrinos, the idea is that we be able to see to the edge of the universe.”

Optical modules for KM3NeT sit on a laboratory table as they await deployment. Credit: KM3NeT, CC BY-NC 4.0

But because they travel almost unimpeded, neutrinos are notoriously difficult to detect. “The only way to do it is to build an absolutely ginormous telescope,” Coyle said.

“The sea is kind of the perfect net for neutrinos,” he said. Very rarely—less than one in a million—a neutrino will collide with a water molecule and produce a nanosecond flash of blue light, called Cherenkov radiation. “We put all these ultrasensitive light detectors at the bottom of the sea, and they sit there and wait to catch the flashes of light made by the neutrinos,” Coyle explained. “The reason we’re in the sea is because it’s big, it’s dark, and it’s very transparent. When we get the flash of light, it doesn’t get absorbed” by the seawater.

Under the Sky and the Sea

KM3NeT’s hundreds of optical detectors will form underwater 3-D grids near the French and Italian coasts. A few detectors are strung together, and strings are dropped vertically into the water at evenly spaced intervals. Each grid will span a kilometer in every direction and will live thousands of meters under water. The video below shows the deployment of one string of detectors.

KM3NeT will have a big scientific impact beyond the field of particle physics, according to Coyle. “To do our measurements with the neutrinos, we need to know the optical transmission of the seawater, the temperatures, and the sea currents. So we have very precise monitoring of the properties of the sea in the vicinity of the telescope.”

“If anything was to suddenly change in the sea, we’d probably be one of the first to notice it,” he added.

KM3NeT is collaborating with oceanographers, seismologists, and biologists, who will make use of its infrastructure. “Essentially, they can have continuous, long-term, high-frequency sampling in situ at the bottom of the sea,” he said.

Other scientists will use the telescope’s power and data cables to support autonomous submarines and crawlers. Projects to sample seafloor sediment, study bioluminescence, and measure carbon dioxide and oxygen content underwater are also in the works.

And KM3NeT’s hydrophones, which it uses for acoustically locating its detectors, pick up other noises, too. “We listened to all the dolphins and the whales around the telescope.” Coyle said.

A Tour de Force of Technology”

KM3NeT is in its early stages of deployment. There are a few operational detectors at the first site off the coast of Sicily and others near Toulon, France, that deployed this year. The team is also exploring a potential third site near Pylos, Greece. Full deployment of the array is expected to take at least 3 more years, but the telescope has already detected some neutrinos.

An artist’s impression of a section of the KM3NeT array. Each vertical line of spherical optical modules is anchored to the seafloor and also buoyed. The network of optical detectors will encompass more than a cubic kilometer of the Mediterranean Sea. Credit: Edward Berbee/Nikh, KM3NeT, CC BY-NC 4.0

Despite the scale of the project, the engineers took care to build a telescope that could withstand the tough conditions at the bottom of the Mediterranean while also minimizing its environmental impact.

“We’re very careful. There’s nothing toxic, nothing really dangerous” used in the detectors, Coyle said. “We have to take a lot of care that all the materials we use can withstand the high pressure…and doesn’t corrode in the seawater.”

“We don’t have a lack of technical challenges,” he said. “It’s quite a tour de force of technology.”

—Kimberly M. S. Cartier (@AstroKimCartier), Staff Writer

AGU’s Virtual Poster Showcase Gives Students a Leg Up

Tue, 06/25/2019 - 12:16

In December 2018, AGU welcomed Earth and space scientists from across the globe to Washington, D.C., for its annual Fall Meeting. The hustle and bustle of more than 28,000 attendees filled the conference center with an atmosphere that was electric. The weeklong event is a wonderful opportunity for students to network, learn in an interactive environment, and gain valuable experience in presenting research to their peers. But what if you aren’t able to attend because of financial or scheduling reasons?

VPS entrants build critical, career-boosting oral and written presentation skills and receive expert feedback.AGU’s twice-annual Virtual Poster Showcase (VPS), launched in 2015, enables students to participate in an online poster competition in which they present their research to peers and judges. VPS entrants build critical, career-boosting oral and written presentation skills and receive expert feedback on the clarity, thoroughness, and competence of their research. Prizes include complimentary AGU membership and Fall Meeting registration. All entrants receive a certificate of participation, earn citations for their abstract, and, most important, are added to the American Geosciences Institute’s GeoRef database.

Prudence Crawmer, a past VPS winner studying environmental studies and geography at Pikes Peak Community College in Colorado Springs, Colo., “encourages students to apply, because if you don’t have money for travel fees, this is a great way to present your project.” During the Fall 2018 session, Crawmer presented her research on collecting local magnetic anomalies using a crowdsourcing app called CrowdMag and credits VPS for making her less nervous about future presentations as she progresses in her academic and professional endeavors.

In a competitive field like the geosciences, presenting research in a succinct, online presentation is a unique experience that students can use to differentiate themselves.Amanda Gerotto is a Ph.D. student researching paleoceanography at the Oceanographic Institute at the University of São Paulo in Brazil and a winner at the Spring 2016 VPS. She most enjoyed the feedback that she received. “I learned a lot about myself,” said Gerotto. “Having recommendations [to incorporate into my research] from that is amazing.” Similarly, Rushana Karimova, a graduate student at York University in Toronto, Ont., Canada, studying carbon dioxide ice properties on Mars, presented her undergraduate thesis research during the Fall 2016 VPS. Her favorite part was getting to speak to so many peers and experts: “People asked me questions about my poster and my presentation, and it was really interesting to see what parts of my work they were more interested in.”

In a competitive field like the geosciences, presenting research in a succinct, online presentation is a unique experience that students can use to differentiate themselves. The VPS program shows that developing alternative means of inclusivity can offer crucial opportunities to geoscience students facing different situations. The future of VPS is bright, and AGU is eager to see the research that young Earth and space scientists will be bringing forth in upcoming showcases.

—Julia Jeanty (jjeanty@agu.org), Talent Pool Intern, AGU; and Sharon Rauch, Career Services Coordinator, AGU

Planning an International Magma Observatory

Tue, 06/25/2019 - 12:14

Magma is the final frontier of Earth’s crust. It is unexplored for good reasons: Extreme temperatures and pressures impede access by scientists and their instruments. Further, no geophysical technique has been shown to satisfactorily locate magma reservoirs. Thus, drilling down to magma might seem impossible. At several sites, however, geothermal energy drilling operations have discovered magma accidentally and safely. One of these sites is Krafla caldera in Iceland.

Beginning in 2014, an international group of scientists and engineers developed a plan, the Krafla Magma Testbed (KMT), to conduct long-term exploration of Krafla’s rhyolite magma reservoir and its surrounding hydrothermal envelope. Our intent is to build surface facilities and subsurface magma portals where independent research teams can conduct experiments. The levels of funding required and the “user facility” organizational structure make such infrastructure analogous to that for telescope arrays and particle accelerators.

We have established a project office in Reykjavík at the Geothermal Research Group Cluster. Research institutes and companies from countries around the world, along with the government of Iceland, have endorsed KMT. We are optimistic that funding for the KMT project will begin within a year and that the facility, once built, can be maintained in an open state for decades.

Drilling Magma

Intentionally drilling into a magma reservoir is unprecedented, but projects to drill molten rock are not new. Intentionally drilling into a magma reservoir is unprecedented, but projects to drill molten rock are not new. Beginning in the 1960s, the U.S. Geological Survey (USGS) began coring into lava lakes on Kīlauea volcano in Hawaii. Foremost among these projects was Kīlauea Iki, a pit crater that had erupted and filled with lava to a depth of 130 meters in 1959. Using small coring rigs, scientists drilled through the crust to the molten zone, retrieving almost perfect core samples. Cold water flowing through the core bit solidified the melt portion into beautiful glass but preserved it unchanged chemically.

Coring of Kīlauea Iki began soon after the eruption ended and continued to 1988, when the last of the melt lens was crystallizing. By the late 1970s, USGS was joined by Sandia National Laboratories in an effort to test the feasibility of extracting energy from magma. In essence, Kīlauea Iki became a test bed of the sort that we envision for unerupted rhyolite magma at Krafla.

All discoveries of unerupted magma have been unexpected and serendipitous. The results of the Kīlauea Iki project were transformational in magma science. Scientists obtained repeated petrologic profiles that traced the melt in time, composition, and space [Helz and Thornber, 1987]. Repeated temperature profiles showed that thermal fracturing at the base of the growing crust allowed water and steam circulation to rapidly transfer heat out of the melt lens [Hardee, 1980].

The location of Kīlauea Iki’s still-molten lava was obvious because it had pooled at the surface, but all discoveries of unerupted magma have been unexpected and serendipitous. The first such discovery began with geothermal drilling into the Kīlauea East Rift in 2005 [Teplow et al., 2009]. After passing through a zone of solid diorite, the drilling encountered crystal-poor dacite magma at a depth of 2,488 meters. The magma flowed 8 meters up the well.

At Menengai caldera in Kenya, geothermal drilling began in 2011, and multiple wells have since penetrated syenitic magma 2 kilometers beneath the caldera floor [Mbia et al., 2015]. Not only were these magma bodies or body surprisingly shallow, but also none of this magma had erupted in recent times.

At the Kīlauea East Rift and Menengai sites, as well as at the Krafla site, there is a heat-conductive “magma lid”: an abrupt transition zone from solid rock to molten rock and a correspondingly extreme temperature gradient as predicted by Carrigan [1984]. An upper “mush zone” of partially crystallized magma, typically seen in lava lakes, is missing.

All of these accidental encounters also share another common feature. Because hydrostatic pressure exerted by the drilling fluid in the borehole is much less than lithostatic pressure on the magma exerted by the overlying rock layers, magma begins to ascend up the borehole. The cold drilling fluid quickly quenches the viscous magma, forming a rock plug. These magma encounters were unexpected, and thus, no measurements or core samples were taken.

In order to use magma (or avoid accidental encounters), geophysical techniques must be developed into accurate prospecting tools by testing them against known magma targets with known properties [e.g., Kim et al., 2019]. The results of unexpected magma encounters also warn against assuming that ash and lava from eruptions fully represent the range of magmas beneath a volcano. These are two of the research challenges that our magma observatory project aims to address.

We chose Krafla caldera for our observatory project (Figure 1) because Iceland Deep Drilling Project‘s IDDP-1 drill hole and some 40 geothermal wells drilled before it have already provided a wealth of descriptive information about this site [e.g., Mortensen et al., 2014]. The Krafla caldera geothermal development project of Landsvirkjun, the National Power Company of Iceland, encountered its first unequivocal penetration of magma in 2007. In 2009, IDDP-1 encountered near-liquidus rhyolite at 2,102 meters, and magma flowed 9 meters up the well.

Fig. 1. Simplified schematic of the magma system beneath Krafla caldera (dashed red line), showing boreholes drilled for geothermal development (gray). The location of one large, near-liquid rhyolite magma body (red) is based on data from the intersection and near-intersection points with the boreholes, as shown. The rhyolite body sits above a region of basaltic magma (blue). The rhyolite and basalt regions may be more complex, with multiple smaller bodies of magma. The planned KMT-1 borehole (purple) closely follows the path of the earlier IDDP-1 project. Credit: J. W. Catley

Fig. 2. KMT-1 will provide the first cored transect of the margin of a magma chamber and the first measurement of heat flow from magma to a hydrothermal system. Results, observed and inferred, from IDDP-1 [Mortensen et al., 2014] are shown here, along with plans for KMT-1 assuming a similar section. A is felsite, B is partially melted felsite, C is crystal-rich rhyolite magma (“mush” that was expected but not observed), and D is near-liquidus rhyolite. Images B and D are element maps from N. Graham and P. Izbekov at University of Alaska Fairbanks’s Advanced Instrumentation Laboratory, color-coded according to silicon dioxide (SiO2) weight percent. Orange is rhyolite melt (now glass) with 75 weight percent SiO2. In image B, it has formed along grain boundaries between plagioclase feldspar (lime green) and quartz (white, 100 SiO2 weight percent). Black is void space. In image D, melt makes up most of the sample, within which euhedral plagioclase, pyroxene (dark green), and ilmenite (black) float. Each field of view is 1 × 1 millimeter. Data from KMT-1 will reveal the depth and temperature relationships of these materials, helping to solve the enigma of why extensively crystallized magma (at C) is not present, even though melting in the rock roof (image B) above the magma should approximately balance magma crystallization. One explanation might be that convection in the magma allows heat given off by crystallization to be extracted from a much larger volume of the magma relative to the volume of the melted static roof.Other wells at Krafla have reached magma or near magma over an area of 3.5 square kilometers. The roof rock (rock layer just above the magma) at IDDP-1 is partially melted felsite (Figure 2). IDDP-1 recorded exceptionally high permeability above the magma, contradicting researchers’ expectation that roof rock would be ductile and therefore impermeable. The resultant long-term flow rates of superheated steam, if channeled to a power station, could produce more than 30 megawatts of electricity from this single well.

Plans for the KMT Observatory

Krafla is the site of the most drilling, geoscience, and monitoring of any magma-hydrothermal system worldwide because of its volcanism, rifting at a major tectonic plate boundary, and robust production of geothermal energy. The public-spirited nature of the field operator, Landsvirkjun, the National Power Company of Iceland (LV), and a supportive local population present an exceptional opportunity for broad science, engineering, and community collaboration.

KMT will be built in phases of increasing complexity, with the first estimated to cost $25 million and the total development to cost some $100 million. For phase I we plan to do the following:

choose the well site close to IDDP-1 so that we drill through the same rock layers drill the well and case it to about 2,050 meters using novel flexible couplings to accommodate thermal expansion and contraction core ahead until we penetrate magma emplace a thermocouple string to the bottom of the hole install a wellhead with a port for insertion of further experiments and pressurize the well with nitrogen to maintain an open hole

Subsequent drilling will provide a time series of observations for the magma-hydrothermal boundary, that is, whether the boundary is getting deeper as the system cools or is rising as the system heats up. We also plan to test extreme sensors (which are also relevant to such applications as aircraft engines and missions to Venus and Io) as well as the casing alloys and cements needed to ensure the long-term operational life spans of superhot boreholes. We will explore spatial variations in the magma body and its envelope and methods of extracting energy from this heat source.

Putting the Knowledge to Use

The KMT observatory will be a rich source of scientific knowledge, but the knowledge we gain will find many practical applications as well.

KMT provides a test of geophysics against (under)ground truth.Assessing volcano hazards is one obvious example of such an application. The first questions people ask about a dangerous volcano are whether there is magma and, if so, where it is. KMT provides a test of geophysics against (under)ground truth. At present, we rely on proxy signals such as microearthquakes and surface deformation that provide untested and nonunique interpretations of what the magma is doing. We will be able to manipulate the fluid pressure in the borehole to generate seismic signals to test our inferences of volcano “unrest.” Ultimately, development of in situ sensors that can detect pressure and temperature changes within a magma reservoir preceding an eruption will yield a vast improvement in the reliability of eruption forecasting.

The geothermal energy industry can also benefit from the KMT observatory. Iceland, one of the hottest regions of Earth’s crust, is an ideal location for an international test bed to accelerate advances in geothermal energy production. Geothermal energy has the least surface footprint of any energy source, usually produces little or no carbon dioxide (CO2), and is continuous (“bed load”).

The KMT project will also contribute to planetary science by serving as an analogue to similar sites on other planets.Ten percent of the human population lives less than 100 kilometers from active volcanoes [Newhall et al., 2017]. Areas near magma are the best places to find high-energy aqueous fluids: superheated or supercritical hydrothermal fluids that transport heat rapidly to the surface [Scott et al., 2017]. At these fluid conditions, the efficiency of converting heat to electric power approaches the level of hydrocarbon-fired power plants [Tester et al., 2007] but without the problem of carbon-based fuels.

KMT can also help to address some fundamental science questions about how the magma-hydrothermal regime works. Both the absence of magma mush at the chamber roof and the high permeability of what should be ductile, impermeable rock near the magma [Mortensen et al., 2014] pose enigmas. The simplest explanation for the absence of crystal-rich magma mush is convection [Carrigan, 1984]. The simplest explanation for high permeability is thermal fracturing [Lamur et al., 2018]. These conclusions suggest a tightly coupled system in which magma rapidly advects (transports) heat to the solidified lid over the magma chamber. Cooling causes contraction, which fractures the lid, keeping it thin and heat conducting. High-energy fluids generated in the fractures can then transport this heat to a power plant. Such a system is efficient and sustainable.

Fig. 3. Students play Magma Drillers, an online game that teaches them basic principles of drilling, geothermal energy, and volcano monitoring, as well as the career paths required. Credit: Ben Kennedy and Jonathan Davidson (design), Elizabeth Moredensky (art)

The KMT project will also contribute to planetary science by serving as an analogue to similar sites on other planets. Rocky planets differentiate (separate into layers of different composition) when melts separate from crystals and these components float or sink. By tracking melting and crystallization in situ, KMT will provide the first view of the final stages of planetary differentiation.

We are developing multiple levels of educational experiences for this unprecedented journey to inner space. For example, through work at the University of Canterbury more than 4,000 students have already taken a virtual field trip to Krafla or played Magma Drillers Save Planet Earth, an online game that lets students plan a geothermal energy drilling site (Figure 3).

Past experience, albeit accidental, shows that we can reach and sample magma. Undertaking a planned rather than an accidental journey to magma is imperative for discovering new fundamental insights, mitigating the perils of eruption disasters, and developing energy alternatives to the hydrocarbon fuels currently poisoning the atmosphere with CO2.

Acknowledgments

This article is written on behalf of the KMT team of scientists and engineers from LV; British Geological Survey, Iceland GeoSurvey, and USGS; consultancies Holmgeirsson, Perma Works, and Pye; government institutes Istituto Nazionale di Geofisica e Vulcanologia, Sandia National Laboratories, Lawrence Livermore National Laboratory, and GeoForschungsZentrum; and the universities of Alaska, Canterbury, Cornell, Lancaster, Liverpool, Munich, and others.

Podcast: Night of the Killer Smog

Mon, 06/24/2019 - 14:03

 The Clean Air Act of 1970 was one of the first and most influential environmental laws passed in the United States. The act sets standards for controlling air pollution that ensure Americans have clean air to breathe.

But why was this law needed in the first place, and what inspired lawmakers to want to regulate air pollution levels?

Two tragedies in the mid-20th century showed lawmakers that air quality was an issue they needed to address.

Industrial mills contributed to air pollution in Pennsylvania cities such as Donora and Pittsburgh, above. Credit: University of Pittsburgh/Carnegie Museum of Art

In late October 1948, a cloud of toxic smog settled over the town of Donora, Pa., and hung there until Halloween. The town was home to the largest nail mill in the world at the time, which burned more coal than the nearby city of Pittsburgh. The poison fog killed 20 residents in 5 days and sickened thousands more in the months that followed.

Just 4 years later, a similar but larger-scale event happened in London, a notoriously polluted city. In December 1952, pollution from coal-fired power plants and chimneys, as well as emissions from new diesel buses, created a smog so thick residents couldn’t see their own two feet. Thousands died, and tens of thousands were sickened by the poison cloud that persisted for 5 days.

In London and Donora, anticyclones settled over the cities and trapped their smoggy air in place, preventing the toxic fog from dissipating high in the atmosphere as usual.The London and Donora smog disasters were due in part to a weather phenomenon known as an anticyclone. In essence the opposite of a cyclone like a hurricane, an anticyclone is a region of high atmospheric pressure. In the cases of London and Donora, anticyclones settled over the two cities and trapped their smoggy air in place, preventing the toxic fog from dissipating high in the atmosphere as usual.

In this Centennial episode of Third Pod from the Sun, physician Devra Davis recounts the effects of the Donora and London smog events and describes why they were so deadly.

A Pennsylvania native who grew up in the town of Donora, Devra shares her memories of living in the polluted town and how the deadly smog affected her family. She also describes the research she conducted on the London smog event and how her work showed the death toll from the disaster was much higher than the British government reported. Finally, Devra recounts how these two tragedies served as catalysts for enacting the first clean air laws in the United States and abroad.

Read more about the Donora smog even in Devra’s book, When Smoke Ran Like Water.

This episode was produced by Lauren Lipuma and mixed by Robyn Murray and Jon Schriner.

—Lauren Lipuma (@Tenacious_She), Contributing Writer

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