In a first-of-its-kind study, a team of researchers led by geoscientist Michael Rawlins at the University of Massachusetts Amherst has shown in fine-grained detail what happens when Arctic permafrost thaws. Focusing on a Wisconsin-sized area of Alaska's North Slope containing hundreds of rivers and streams flowing into the Beaufort Sea, the team analyzed 44 years of model data at one-kilometer grid resolution, revealing how massively runoff is increasing, the increased loads of previously frozen carbon flowing through northern Alaska's rivers and how the thawing season has extended into late-summer and fall.
Author(s): Jiheon Song, Jeff Candy, Emily Belli, and Jungpyo Lee
The role of zonal flow (ZF) in the turbulence saturation of trapped electron modes (TEM) in magnetically confined plasmas is revisited. In this study, we examine ZF excitation and saturation mechanisms in TEM turbulence using detailed free-energy transfer diagnostics from nonlinear gyrokinetic simul…
[Phys. Rev. E 113, 045201] Published Wed Apr 01, 2026
Author(s): Xufei Xie et al.
Detailed investigation of the x-ray drive on the capsule at the center of the hohlraum is crucial to solve the “drive deficit” problem in inertial confinement fusion. A pioneering work for probing the drive flux at the hohlraum center by simultaneously measuring the re-emitted flux and shock velocit…
[Phys. Rev. E 113, 045202] Published Wed Apr 01, 2026
Author(s): Cunbo Zhang, Zongqiang Ma, Yang Song, Cheng-quan Fu, Zhengfeng Fan, Anmin He, and Pei Wang
Within the equilibrium-diffusion approximation for radiation, we perform a linear stability analysis of the compressible Rayleigh-Taylor instability in a stratified, isothermal background. Radiation alters the growth rate by modulating the fluid's effective compressibility. Radiative diffusion enhan…
[Phys. Rev. E 113, 045203] Published Wed Apr 01, 2026
SummaryGlaciers are key components of the global climate system and sensitive indicators of environmental change. Their dynamics generate diverse seismic signals, whose source mechanisms offer valuable insights into their internal stress conditions. While moment tensor inversion has been applied to icequakes on a few alpine and polar glaciers, it had not yet been implemented on the Argentière Glacier (French Alps). In this study, we conduct a systematic characterization of icequake source mechanisms based on a dense dataset of 14 057 near-surface events recorded by 98 3-component sensors deployed at the surface of the glacier during the RESOLVE project. We apply a full waveform inversion method to jointly reconstruct the moment tensor and the source time wavelet for each event. The moment tensor Green’s functions used in the inversion are computed through numerical modeling of elastic wave propagation in a 3D medium, incorporating real surface topography. This approach allows us to exploit the full complexity of the recorded seismic signals and to move beyond previous analysis based on simplified models and single-component data. The results reveal a clear dominance of opening-type (tensile crack) mechanisms, consistent with extensional stress regimes at the crevasse locations, with principal stress direction almost perpendicular to the local crevasse orientations. The exceptional size of the catalog enables a detailed investigation of spatial patterns in source mechanisms, particularly highlighting structural complexity in the heavily crevassed downstream zone. The distribution of extensional and compressional mechanisms further indicates a highly heterogeneous stress field at the glacier surface, influenced by local crevasse geometry. Depth-dependent variations in the reconstructed moment tensors suggest that deeper events tend to involve more isotropic components, likely reflecting pressure-driven failure under overburden stress. These findings demonstrate the potential of full waveform inversion to characterize the source mechanisms associated with the icequakes on a glacier. This work represents a significant step toward integrating seismological modeling with glaciological interpretation in alpine environments.
Communities worldwide rely on reservoirs for drinking water, hydroelectric power, irrigation, and more. These critical freshwater resources are affected by seasonal and long-term changes; water levels in reservoirs can dip during hot summer months or due to prolonged drought, or can flood after a particularly strong storm. Despite their importance, there are key gaps in our knowledge of reservoir structure and dynamics. Two recent papers published in Scientific Data use Landsat data to help fill in those gaps.
The circular economy concept is often thought of as a model to eliminate waste and pollution—but when applied thoughtfully, circular approaches can create jobs, strengthen local economies, improve public health and more, according to new research led by Charles Darwin University (CDU).
As global temperatures climb, rainfall patterns are shifting in ways that could put water resources and agriculture under increasing strain, a new study published in Water Resources Research suggests.
Scientific expeditions require months of planning before scientists can acquire the first data. A bark cuts through the Arctic silence, waking Anna up. She slept only three hours after collecting the last sample. Anna reaches for her rifle, exits the tent, and steps onto the midnight ice. She pets the guard dog she rented a few days earlier. It might be a false alarm, but she scans the darkness for polar bears, hoping her training pays off. She cannot afford to lose the samples. Nor her life.
SummaryKinematic characteristics (creeping or locked) and high-precision seismic catalogs can constrain the shallow (<20 km) slip pattern of active fault zone. We collect Sentinel-1 Synthetic Aperture Radar (SAR) images and extract a high-resolution deformation velocity field along the active Laohushan-Haiyuan (LHS-HY) fault zone in the northeastern margin of the Qinghai-Tibet Plateau. We invert the shallow fault coupling and slip distribution using two-dimensional (2D) and three-dimensional (3D) models, indicating that the fault zone exhibits an alternating pattern of large strong coupling asperities and creeping zones, and the deep slip rate decreases from 5.2 mm/yr in the west to 3.4 mm/yr in the east, accompanied by a transition from strike-slip to dip-slip components. Then we calculate cumulative seismic energy release, seismic slip rate, and statistical parameters including $b - \textit{value}$, coefficient of variation of seismicity interevent times, and Nearest-Neighbor Distance (NND) with regional seismic catalog. The geodetic and seismic results demonstrate a complex shallow slip pattern in the fault zone. The following characteristics are highlighted. A significant throughgoing locked-creeping transition zone with variable depth range extends from the eastern part of the Laohushan segment (LHS) to the eastern segment of Haiyuan Fault (HYE). A shallow (<6 km) creeping zone with weak coupling and seismicity in the western HYE segment differs from the shallow part of the locked-creeping transition zone between the eastern LHS segment and the western part of the western segment of Haiyuan Fault (HYW). A transition zone with strong coupling and active seismicity in the eastern HYE segment ranges from 4 km to 12 km in depth. The results provide new insights into the shallow slip behavior of the LHS-HY fault zone, and offer valuable references for seismic hazard assessment in the region.
SummaryAccurate sensor orientation estimation is critical for reliable seismological processing, especially when rotating three-component seismograms is required. In this study, we determine the sensor orientation angles of 676 broadband stations of ChinArray-II deployed in northeastern Tibet between August 2013 and June 2016. The polarizations of both Rayleigh waves and teleseismic P-waves are used to estimate the azimuthal deviation. The results demonstrate that both approaches are consistent and approximately 600 stations are well-aligned, with mis-orientation angles less than 10°. The remaining stations exhibit various orientation problems, such as vertical component reversal and temporal variations in sensor alignments. Moreover, detailed multi-event analysis reveals that three-component sensor gain discrepancies may lead to failures of both P- and Rayleigh-wave approaches, while post-validation of multi-event estimation can identify such issues. Compared with previous studies, our results provide comprehensive sensor orientation information and indicate that combining noise level and wave polarization yields robust estimations.
SummaryThe South Peru subduction zone is a complex, highly active region, which has hosted four Mw 8 + earthquakes over the last 100 years. It marks the transition between the flat slab associated with the Nazca Ridge subduction in the North and more steeply dipping subduction in the South, causing the slab to contort and affecting seismicity patterns in the region. In this study, we present the first high-density, high-quality seismic catalog of the region between the arc and the trench, totaling 166 825 events between January 1st 2022 and December 31st 2024, including 125 467 well-located ones. We first picked and associated phases using PhaseNet and PyOcto, then located the resulting events with NonLinLoc-SSST and GrowClust3D. Finally, we derived a new slab model from the seismicity, allowing us to classify the earthquakes as upper plate (16 per cent), interface (12 per cent), lower plate (68 per cent), outer rise (0.20 per cent) and human-related (3.1 per cent).The region is broadly divided into four subregions with different seismicity patterns and slab geometries: the flat slab, with intense interface and intraslab activity, the slab transition zone, where the plate contorts to accommodate its change in geometry, the Arequipa region, with intense upper plate seismicity but very low intraslab and interface seismicity, and the North Chile region, with a large band of dense intraslab seismicity.We find that in the flat slab region, the Nazca Ridge is linked to the presence of dense seismicity close to the trench, and seismic swarms hinting at the presence of slow slip. Meanwhile, the intraslab seismicity in that region is organized in trench-parallel bands which are likely related to slab bending. In the slab transition region, we image multiple orthogonal faults just south of the slab contortion, suggesting a damaged slab. Further south, in the Arequipa region, upper plate seismicity forms a large, trenchward-dipping structure seemingly connected to the Incapuquio fault at the surface. Finally, in North Chile, the deep band of intraslab seismicity appears to locate further downdip as we move to the north, perhaps reflecting changes in slab properties.
In recent years, the Prairies have seen bigger swings in climate conditions—very wet years followed by very dry ones. That makes an already unpredictable landscape even harder to forecast, with real consequences for flood preparedness and water quality.
Wild animals are not just inhabitants of the natural world. Many also act as natural landscape engineers, reshaping Earth's surface as they burrow, feed, and build shelters that move soil and sediment across ecosystems. From animals disturbing riverbeds to burrowing species redistributing soil, wildlife constantly modifies the physical structure of landscapes through everyday activities.
Earth has already exceeded its ability to support the global population sustainably, with new research warning of increasing pressure on food security, climate stability, and human well-being. However, slowing population growth and raising global awareness could still offer humanity some hope.
Volcanoes are both captivating and disastrous. Most are likely familiar with the common short-term dangers associated with them: explosive forces, lava, and even atmospheric particles disrupting air traffic. But researchers also explore longer-term impacts of eruptions, as their contributions to broader climate patterns are important, but not well understood. For example, it's known that ejected material can reach high into the atmosphere and cause local or even global cooling to some degree.
Experiments by University of Leeds researchers, published in Earth's Future, have shown that thawing of permafrost makes it between 25 and 100 times more permeable, allowing more climate change forcing gases to escape.
Some Arctic regions regain their "greenness" within a decade of a sudden permafrost collapse, while others can take a century or more to recover, researchers report in a new study. The difference is directly related to each site's gross primary productivity, a measure of its photosynthetic capacity, the researchers discovered. This finding will allow scientists to accurately predict how long it will take a specific site to recover after a permafrost collapse.
SummaryThe Orientale Basin is the youngest and best-preserved multi-ring impact basin on the Moon. It is approximately 930 km in diameter and comprises three concentric rings—the Cordillera, Inner Rook, and Outer Rook rings. We used Gravity Recovery and Interior Laboratory (GRAIL) mission gravity data (GRGM1200B, truncated to degree 660) to invert the three-dimensional (3D) density structure associated with the basin’s mascon and ring-related crustal anomalies. To separate longer and shorter-wavelength signals, we performed inversions using (1) spherical harmonic degrees 2–660 to characterise the basin’s deep structure and (2) degrees 60–660 to highlight crustal-scale heterogeneity. The inversion with degree and order of 2–660 resolves a basin-wide central positive density anomaly beneath the inner depression, extending from a depth of ∼16–80 km, corresponding to uplifted mantle. This anomaly persists below the crust–mantle boundary; however, its deep continuation should be interpreted cautiously because it may partially reflect vertical smearing in the gravity inversion. Nonetheless, the spatial association of this anomaly with a mascon rooted in the upper mantle is compatible with impact-driven uplift of dense material from depth, followed by post-impact thermal evolution and relaxation processes. The inversion with degree and order of 60–660 indicates alternating positive and negative density anomalies associated with the ring system. Prominent ring-parallel positive anomalies occur along the Outer Rook Ring and Cordillera Ring, extending to ∼30–35 km depth and exhibiting a density contrast of ∼60–200 kg/m3. The geometry and lateral continuity of these anomalies across multiple rings support an interpretation of ring-controlled crustal heterogeneity, consistent with either intrusion and structurally focused modification along ring-related discontinuities or impact-generated fracturing that provided pathways for magma ascent. The results of this study provide quantitative constraints on the depth, magnitude, and spatial distribution of density anomalies associated with the Orientale mascon and ring system, thereby improving the subsurface framework for regional geological interpretation and supporting future lunar landing-site geophysical investigations and in situ sampling. Based on the inferred crustal density architecture, we propose that future geophysical sampling efforts should prioritise the Outer Rook Ring and Cordillera Ring, where the observed ring-parallel anomalies may provide insights into crustal modification processes and the composition of the lunar interior.
In recent years, residents of Spain, France and the UK have looked up to see an eerie sight: deep orange sunrises and skies thick with a yellowish haze. These hazy skies often deposit "blood rain," rust-colored precipitation that leaves a fine grit on cars and windows.
