All articles tagged with #seismology
Researchers trained machine-learning tools on eight years of borehole strain data along California’s San Andreas Fault near Parkfield, identifying slow-slip events that often coincide with nearby low-frequency earthquakes, suggesting slow slipping contributes to fault stress and could inform future earthquake forecasting efforts.
Seismic data from NASA's InSight reveal a long-lived magma system beneath Mars' crust, with an upper basalt layer and a deep ultramafic region formed by transcrustal magmatism; this process, not requiring plate tectonics, could have helped Mars stay warm and water-rich in the past, hinting at possible habitability.
A machine-learning study analyzes 2018–2021 seismic data to map a 250-km, razor-sharp edge of the Yakutat microplate beneath Alaska, extending under the North American plate and along the Denali fault. This hidden edge illuminates how the subducted slab shapes stress and earthquake nucleation in the region, including the 2002 magnitude-7.9 Denali quake, and suggests a broader, dynamically interacting plate boundary that influences regional volcanic activity.
Seismic data indicate Earth's solid inner core, long spinning slightly faster than the surface, slowed to match the surface around 2009–2010 and has since fallen behind, effectively drifting backward relative to the rest of the planet. The motion is a relative one (to the mantle) and likely part of a ~70-year oscillation that also influences length of day and the magnetic field; the evidence is indirect and debated, with ongoing work to confirm the oscillation model over the coming decade.
Seismic data from NASA’s InSight reveal a surprisingly thick ultramafic lower crust and a long-lived magmatic plumbing system beneath Mars, indicating crustal evolution without plate tectonics and suggesting such magmatic activity could support habitable environments on rocky worlds beyond Earth.
A 5.6 magnitude quake near Willits in Mendocino County rattled Northern California, with damage but no injuries, as several strong earthquakes occurred worldwide on the same day. Seismologists say there’s no evidence of a connection and that the timing is coincidental; inspectors are assessing damaged buildings, and officials stress the importance of ongoing earthquake preparedness in California.
A 2011 magnitude-9 earthquake off northeastern Japan generated an unusually strong ScS wave that travelled down to about 2,890 km, reflected off the outer core, and returned to the surface 13 minutes later, prompting a near-simultaneous 5–6 mm eastward shift across Japan and likely triggering tiny slip on stressed faults. This is the first observation of a core-reflected wave delivering measurable surface motion, with implications for how giant earthquakes are modeled for seismic hazard.
Analysis of Japan’s GNSS data from the 2011 magnitude-9.0 Tōhoku earthquake suggests a seismic wave returning from the core–mantle boundary (ScS) may have triggered a broad, millimeter-to-centimeter fault slip across a large plate boundary, producing tiny but detectable eastward shifts and an energy release comparable to a magnitude 7.5 quake, potentially the first known example of wave-triggered slip from a core-reflected seismic wave; findings published in Science.
GPS data show an eastward, step-like ground shift of up to 6 millimeters across nearly all of Japan about 15 minutes after the 2011 magnitude-9 Tohoku quake. Researchers say a large ScS seismic wave traveled deep into Earth, reflected off the core, and returned to the surface, reactivating plate boundaries and causing the uniform shift—a first suggested observation of this type of wave influencing the surface and with implications for understanding aftershock hazards across subduction zones.
Researchers analyzed data from 49 seismic stations across East Antarctica with a deep-learning detector, identifying about 510 deep, intermediate-depth earthquakes (magnitudes 1.6–3.5) clustered 100–150 km beneath the David Glacier. Occurring far from plate boundaries, these intraplate quakes are likely driven by rock bending from high-temperature mantle and a nearby lithospheric boundary between East and West Antarctica, illustrating how AI can reveal hidden seismic activity.
AI-driven reanalysis of two decades of seismic data from 49 stations uncovered more than 500 previously unknown earthquakes about 60–90 miles (100–150 km) beneath David Glacier in East Antarctica. These intermediate-depth quakes (magnitude 1.6–3.5) occur far from plate boundaries, suggesting a more seismically active interior Antarctica and potentially prompting a reevaluation of continental tectonics. The study, published in Science, also highlights AI’s power to reveal hidden seismic activity in other regions, while not posing a threat to the ice sheets.
A previously mysterious 1979 Utah quake—deep beneath the crust at about 55 miles down—kicks off new research identifying eight later deep earthquakes in the upper mantle near the Wyoming Craton. Scientists say these mantle quakes are archetypal continental mantle events driven by slow mantle flow around cratonic roots, lack foreshocks/aftershocks, and illustrate a tectonic regime at extreme depths that differs from crustal earthquakes.
Scientists reviewing a 1979 northern Utah quake (magnitude 3.8) and eight later deep earthquakes have confirmed they originate in the upper mantle, dozens of miles below the crust, near the Wyoming Craton. The findings, published in The Seismic Record, suggest mantle flow around the craton triggers these deep continental earthquakes, a type of seismic activity that operates very differently from crustal quakes and may vary greatly in size over geologic timescales, underscoring how much about deep Earth remains to be learned.
New measurements indicate that stress along the San Andreas Fault has reached a 1,000-year high, signaling an elevated probability of a major earthquake in the region.
A powerful 7.8-magnitude earthquake struck part of southern Philippines, triggering concern over a potential tsunami along some coastlines as authorities monitor the region for aftershocks and issue advisories.