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How much worse could western wildfires get? New modeling changes projections

Phys.org: Earth science - Tue, 05/19/2026 - 02:00

Across the western United States, wildfires are increasing in size and intensity. As the climate continues to warm, more extreme wildfires will reshape landscapes and pose a growing risk to human health and natural ecosystems throughout the West.

Seismicity and Stresses in the Eastern part of the Amazon Craton: Implications for the Intraplate Stress Field in South America

Geophysical Journal International - Tue, 05/19/2026 - 00:00

SummaryDespite generally low seismicity typical of intraplate regions, magnitudes larger than 6 have occurred in the Amazon craton. The installation of permanent stations of the Brazilian Seismic Network in the Amazon around 2014, the Vale 5-station network in the Carajás mineral province in 2019, and a 30-station temporary deployment (October2021-March/2024) significantly improved earthquake detectability in the eastern part of the Amazon craton. A review of the seismotectonic characteristics of the oldest, Eastern part of the Amazon craton is presented here. Seismicity is not uniform, and areas of higher seismicity are identified, such as in the northern part of the Tapajós-Parima province and along the eastern border of the craton. No clear correlation with the main trends of faults was observed. Contrary to Central and Eastern Brazil, seismicity is not directly correlated with lithospheric thin spots in the Amazon Craton but tends to occur in the flanks of thick keels (“craton edge” effect). A possible influence of free-air gravity anomalies was noticed suggesting that flexural stresses contribute to control seismicity. Five new focal mechanisms are presented for the eastern edge of the Amazon craton, indicating a stress field with NW-SE compression and NE-SW extension. An updated map of the stress field for mid-plate South America shows that the maximum horizontal stresses vary from E-W in SE Brazil, NW-SE in central Brazil and SW-NE in the north. This pattern can potentially be explained by upper mantle flow, provided more detailed convection models are used.

Rethinking Electrokinetic Signals Before Earthquakes: Insights from Finite-Fault Modeling

Geophysical Journal International - Tue, 05/19/2026 - 00:00

SummaryElectrokinetic signals generated by coupled stress–fluid processes are increasingly recognized as indicators of fault-zone dynamics prior to earthquakes. However, their interpretation is often limited by the common reliance on point-source approximations, which neglect the inherently distributed nature of stress accumulation and fluid migration along fault planes. Here, we develop a quasi-static finite-fault electrokinetic framework in which coupled stress and fluid perturbations are represented as spatially distributed, time-evolving sources. The approach combines an extended Luco–Apsel–Chen generalized reflection and transmission method with a point-source superposition scheme, enabling efficient simulation of electrokinetic responses to area sources in layered porous media. Numerical results reveal that the horizontal components of geoelectric fields in the coupled stress–fluid system are highly sensitive to fluid-source geometry, whereas vertical components primarily reflect stress loading. Spatial variability in initiation time, arising from finite-rate fluid migration, further introduces waveform complexity, amplitude modulation, and multi-stage temporal evolution in surface signals. Notably, we find that the directional variations of the geoelectric field provide a robust diagnostic for distinguishing fluid-driven from stress-induced signals, with angular misalignments reaching up to 16.6°. These results establish a quantitative framework for interpreting near-fault electrokinetic signals and for guiding monitoring strategies aimed at constraining fault-zone fluid pathways and stress evolution.

Sea level rise is swallowing US Mid-Atlantic farmland faster than expected, study finds

Phys.org: Earth science - Mon, 05/18/2026 - 22:10

Ghost forests, the cemetery-like groupings of dead trees killed by saltwater intrusion, have become haunting symbols of sea level rise overtaking land along the Mid-Atlantic coast. But a new study published in Nature Sustainability, led by William & Mary's Batten School & VIMS, points to even more dramatic land losses in the region's coastal farmlands, where the rate of marsh encroachment is happening nearly twice as fast.

Southern Ocean intermediate waters may hold key to Earth's carbon dioxide history

Phys.org: Earth science - Mon, 05/18/2026 - 20:00

Researchers at National Taiwan University and partner institutions have uncovered new evidence that Antarctic Intermediate Water (AAIW)—a distinct layer sitting 500–1,500 meters below the ocean surface—played a pivotal role in a major atmospheric carbon dioxide transition that occurred roughly 450,000 years ago.