Publication date: Available online 20 January 2025
Source: Advances in Space Research
Author(s): Jiandong Hao, Hong Cai, Xianyuan Zhang, Lei Zhang, Xingji Li, Yibo Chen
Publication date: Available online 20 January 2025
Source: Advances in Space Research
Author(s): A.V. Popkova, M.S. Pshirkov, A.V. Tuntsov
Clouds, composed of tiny water droplets or ice crystals, play a vital role in regulating Earth's climate by influencing the amount of solar radiation that reaches the surface. The cloud phase significantly impacts the surface energy balance as liquid water clouds reflect more radiation than ice clouds.
Using a nearly 200-year record of lava chemistry from Kīlauea and Maunaloa, Earth scientists from the University of Hawai'i at Mānoa and colleagues revealed that Hawai'i's two most active volcanoes share a source of magma within the Hawaiian plume. Their discovery was published recently in the Journal of Petrology.
A study reveals that fire emissions in the Amazon and Cerrado are largely driven by the smoldering combustion of woody debris. This crucial discovery highlights the significant influence of fuel characteristics on fire emissions, with wide-ranging implications for global carbon cycles, air quality and biodiversity.
There's often little warning when a tsunami strikes, but a research team at USF aims to improve the forecasting of these hazardous events for communities that are most at risk.
The Earth's surface is constantly reshaped by the movement of tectonic plates, which make up the continental crust on which we are living. These tectonic plates are in continuous motion, and when one plate is pushed under another, it is called "subduction." These processes play a crucial role in shaping the Earth's landmasses, including the islands of Japan, over several hundred million years.
Author(s): Andrey M. Lipaev, Vadim N. Naumkin, Sergey A. Khrapak, Alexandr D. Usachev, Oleg F. Petrov, Markus H. Thoma, Michael Kretschmer, Cheng-Ran Du, Oleg D. Kononenko, and Andrey V. Zobnin
An analysis of lattice wave spectra in a three-dimensional dusty plasma structure formed in a direct current gas discharge with alternating polarity under microgravity conditions is reported. The spectra are determined using the Fourier transform of microparticle velocities, measured by tracking mic…
[Phys. Rev. E 111, 015209] Published Mon Jan 27, 2025
SummarySite-specific Probabilistic Tsunami Hazard Assessment (PTHA) is a powerful tool for coastal planning against tsunami risk. However, its typically high computational demands led to the introduction of a Monte Carlo Stratified Importance Sampling (SIS) approach, which selects a representative subset of scenarios for numerical inundation simulations. We here empirically validate this sampling approach, for the first time to our knowledge, using an existing extensive dataset of numerical inundation simulations for two coastal sites in the Mediterranean Sea (Catania and Siracusa, both located in Sicily, Italy). Moreover, we propose a modified importance sampling function to prioritise seismic tsunami scenarios based on their arrival time at an offshore point near the target site, in addition to their wave amplitude and occurrence rate as leveraged in the previous work. This sampling function is applied separately in each earthquake magnitude bin, and allows denser sampling of near-field earthquakes to whose variations tsunamis are very sensitive. We compare the confidence intervals of the offshore PTHA estimates obtained with the new and the original importance sampling functions. Then, we benchmark our onshore PTHA estimates obtained with both functions against the inundation PTHA calculated using the full set of scenarios. We also test the assumption that onshore random errors follow a normal distribution, as found previously for the offshore case. As a result of the benchmarks, we find that the SIS approach works satisfactorily. Introducing the arrival time as an additional sampling factor enhances the precision of the estimates of both the mean and the percentiles for the two coastal sites considered. With this modification it is possible to deal efficiently with heterogeneous near-field earthquake sources involving coastal deformation at Catania and Siracusa, in addition to regional crustal and subduction sources. By comparing the sampling errors with the model (epistemic) uncertainty, an optimal trade-off between the number of simulations employed and the uncertainty of the PTHA model can be found, even for such a complex situation. A relatively small number of scenarios, on the order of a few thousand, is sufficient to perform site-specific PTHA for practical applications. These numbers correspond to 4–8% of the already reduced ensembles used in previous assessments at the same sites.
SummaryThe Pamir tectonic zone originates from the intense collision of the Indo-Eurasian plate. Identifying the faults in the Pamir region region is essential for elucidating the collision mechanism and seismic characteristics. This paper compares the effect of the two-dimensional discrete wavelet transform (DWT2D) and the non-subsampled shearlet transform (NSST) on gravity field separation through synthetic model gravity field experiments. The results show that NSST can avoid the Gibbs phenomenon of DWT2D and better maintain the gravity field distribution. The surface gravity disturbances data of the Global Gravity Model Plus (GGMplus) with a high-spatial resolution (7.2 arcsec or approximately 200 m) is employed to separate the region-residual gravity fields in the neighbouring domain of the Pamir region based on the NSST. Furthermore, the gravity gradient tensor (GGT) is computed, and the correspondence between the GGT and the location and strike of the surrounding faults is analyzed. The results show that the GGT component and its various combinations can effectively identify shallow and deep faults, the residual field GGT and its combinations can effectively identify the distribution and direction of shallow faults, and the regional field GGT and its combinations can effectively identify the distribution and direction of deep faults. The existence of north-south trending faults in the Pamir-Hindu Kush region is widely accepted. However, our study has revealed an east-west trending concealed fault in the deep areas of the Hindu Kush (Depth > 200 km). This finding provides significant insights for studying the bidirectional subduction of the Indian and Eurasian plates. This research not only helps us to analyze the tectonic characteristics of the shallow and deep parts of the region separately but also provides complementary information for investigating the distribution of deep underground faults, especially when fault inversion of intermediate to deep source earthquakes is limited by factors such as uncertainty in source depth and complexity of seismic wave velocities.
SummaryIn Pakistan, the relative displacement between the Indian and Eurasian plates is accommodated by a left lateral transpression zone comprising the Chaman and Ghazaband faults and the Sulaiman Range. The current tectonic deformation of the Sulaiman Range is known only from some focal mechanisms and a few neotectonic studies. In this study, we propose an InSAR quantification of current tectonic deformation using the Sentinel 1 satellite. Velocity maps for the ascending and descending tracks enabled us to locate active faults affected by creep: the Harnaï and Kingri strike-slip faults, and the Gwal-Bagh thrust. We propose a numerical simulation that considers these faults as well as the level of detachment fold-and-thrust belt. Our results suggest the existence of out-of-sequence deformation along the Gwal-Bagh thrust, creep along the Harnaï and Kingri strike-slip faults, and slip along the décollement of the Sulaiman Range. The eastern part of the Sulaiman Range is characterized by a partitioning of the deformation with a left lateral strike-slip along the N170° Kingri fault and an eastward thrust. In contrast, the western part is characterized by north-south compressive deformation associated with right lateral strike-slip on the Harnaï N120° fault. Modelling of the co-seismic deformation of the 21 October 2021 earthquake shows that this earthquake occurred on a fault with a ramp geometry but affected by a strike-slip motion.
Abstract
The Solar wind Magnetosphere Ionosphere Link Explorer (SMILE) was proposed to the Chinese Academy of Science (CAS) and the European Space Agency (ESA) following a joint call for science missions issued in January 2015. SMILE was proposed by a team of European and Chinese scientists, led by two mission Co-PIs, one from China and one from Europe. SMILE was selected in June 2015, and its budget adopted by the Chinese Academy of Sciences in November 2016 and the ESA Science Programme Committee in March 2019, respectively. SMILE will investigate the connection between the Sun and the Earth using a new technique that will image the magnetopause and polar cusps: the key regions where the solar wind impinges on Earth’s magnetic field. Simultaneously, SMILE will image the auroras borealis in an ultraviolet waveband, providing long-duration continuous observations of the northern polar regions. In addition, the ion and magnetic field characteristics of the magnetospheric lobes, magnetosheath and solar wind will be measured by the in-situ instrument package. Here, we present the science goals, instruments and planned orbit. In addition the Working Groups that are supporting the preparation of the mission and the coordination with other magnetospheric missions are described.
Nature Geoscience, Published online: 27 January 2025; doi:10.1038/s41561-024-01637-5
Fire emissions in the Amazon and Cerrado biomes are mainly produced from smouldering combustion of woody debris, according to observationally constrained fire emissions inventories.
Publication date: Available online 20 January 2025
Source: Advances in Space Research
Author(s): Jie Wang, Zilong Cheng, Guanwei He, Hao Yuan
SummaryThe central Pamir plateau moves northward and collides into Eurasia at a rate that varies significantly over its 600 km-wide extension. However, the active structures accounting for such internal shear strain remain enigmatic. In this study, we use Interferometric Synthetic Aperture Radar (InSAR) data to investigate the coseismic and postseismic deformation of the ${M}_w6.9$ Sarez earthquake on 23 February 2023. Using a Bayesian framework, we find the most likely seismogenic fault geometry and explore the full solution space of slip distributions. Our results highlight the mainshock ruptures a nearly NNE fault dipping to the southeast. The finite-fault model exhibits a purely left-lateral strike-slip mechanism with little to no slip reaching the surface. Most of the coseismic slip remains confined to a depth of ∼5 to 20 km, consistent with a large shallow slip deficit. Postseismic afterslip, which decays rapidly within the month following the mainshock, cannot compensate for such coseismic shallow slip deficit. Integrating the analysis of coseismic slip, postseismic deformation, and regional seismic activity, we argue that in the central Pamir, significant north-south shear strain is accommodated along multiple parallel faults, often unmapped, hence posing a significant seismic hazard.
SummaryDetailed investigations of aseismic slow slip events (SSEs) are crucial for estimating the strain budget and SSE mechanisms within subduction zones. The Suruga Trough, which includes the Tokai seismic gap, is an important area in Japan from a hazardous perspective. However, the aseismic slip history of this trough following the 2011 Tohoku earthquake is difficult to determine as a result of post-seismic deformation caused by the earthquake. In this study, we provided detailed imaging of the interplate aseismic slip in the Suruga Trough after the 2011 Tohoku Earthquake by applying a network inversion filter to global navigation satellite system data and considering viscoelastic deformation and afterslip caused by the earthquake. The analysis revealed the 2012 Shima long-term SSE (l-SSE), 2013-2016 Tokai l-SSE, 2017-2020 Shima l-SSE, and 2023-2024 Atsumi+Tokai l-SSE, with the slip area expanding to the area adjacent to the Tokai seismic gap from July 2023, consequently changing the stress state to promote the anticipated Tokai earthquake. The findings of this study suggest that the recurrence interval of the Tokai slow slip ranges from 10 to 13 years, with a duration of approximately 4-5 years and a total magnitude ranging from 6.5 to 7.1. The l-SSE zone shows that the upper-limit temperature threshold, which is the temperature at the upper bound of the l-SSE zone aligning the 350°C isothermal line in the Tokai segment, does not hold in the Suruga Trough. The change in strike direction of the l-SSE zone suggests that a discontinuous factor controls the l-SSE occurrence, such as high pore pressure caused by fluid infiltration to the plate interface. Furthermore, we explored a gap between the short-term SSE (s-SSE) and l-SSE zones, and the findings indicated a non-continuous transition from l-SSE to s-SSE, thus providing insights into the discontinuous factors that regulate l-SSE and s-SSE generation. The recurrence interval (10–13 years) and duration (4-5 years) of the Tokai SSEs are long, and their moment rates (1015.8Nm/day) are low compared to those of the l-SSEs in other regions. The SSE parameters suggest that the scaling law may not apply to SSEs in the Suruga-Nankai Trough with the prolonged duration.
Antarctic krill swimming between the Southern Ocean's surface and seafloor depths, make a "surprisingly small" contribution to the carbon export "highway" compared to their fast-sinking feces, according to research published in Science.
A study led by The University of Western Australia has revealed new insights into the landscape profile of the Avon River Critical Zone Observatory in Western Australia.
A large international team of researchers with a wide variety of backgrounds has found evidence that carbon storage below seaweed farms can accumulate as much carbon as some Blue Carbon habitats. In their study published in Nature Climate Change, the group analyzed data from multiple seaweed farms around the globe.
Nature Geoscience, Published online: 24 January 2025; doi:10.1038/s41561-025-01640-4
The cause of episodes of unrest at caldera volcanoes is often unclear. Analysis of the sulfur composition of gas emissions at Campi Flegrei in Italy suggests a magmatic origin of the recent unrest at this hazardous caldera.
