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Paleoseismology and paleogeodesy using coral microatolls Paleoseismology and paleogeodesy using coral microatolls

Establishing the rupture extent and slip distribution of individual paleo-earthquakes is vital for assessing fault behavior including the persistence of rupture segmentation, recurrence patterns, and similarity of successive events, key issues in both fault mechanics and hazard assessment. Techniques with high temporal and geodetic precision as well as a wide distribution of study sites...
Authors
Belle E. Philibosian

Remote single-station seismic monitoring of the July–October 2022 earthquake swarm at Tau volcano, American Samoa Remote single-station seismic monitoring of the July–October 2022 earthquake swarm at Tau volcano, American Samoa

From July to October 2022, a non-eruptive volcanic earthquake swarm occurred within ~15 km of Taʻū Island, located in eastern American Samoa. Felt reports from local residents were the only available information about the swarm when it started, as American Samoa lacked a seismic monitoring network. We developed a consistent single-station catalog for the entire swarm, using seismic data...
Authors
Clara Yoon, Robert Skoumal, Andrew J. Michael, Arthur D. Jolly, Andria P. Ellis, Drew T. Downs, Peter Dotray, Natalia I. Deligne, Jefferson Chang, Ninfa Lucia Bennington, Aaron Wech, Matthew M. Haney, Alicia J. Hotovec-Ellis, Elinor Lutu-McMoore, Marcus Langkilde

A high-resolution 3-D P-wave velocity structure of the south-central Cascadia subduction zone from wide-angle shore-crossing seismic refraction data A high-resolution 3-D P-wave velocity structure of the south-central Cascadia subduction zone from wide-angle shore-crossing seismic refraction data

This study addresses a significant gap in understanding the features of the south-central Cascadia subduction zone, a region characterized by complex geologic, tectonic, and seismic transitions both offshore and onshore. Unlike other segments along this margin, this area lacks a 3-D velocity model to delineate its structural and geological features on a fine scale. To address this void...
Authors
Asif Ashraf, Emilie Hooft, Douglas Toomey, Anne Trehu, Sarah Nolan, Erin Wirth, Kevin M. Ward

Examining the role of elevated and sustained strain in dynamically triggering earthquakes on the Anza section of the San Jacinto fault Examining the role of elevated and sustained strain in dynamically triggering earthquakes on the Anza section of the San Jacinto fault

Microearthquakes can be dynamically triggered in southern California by remote earthquakes. However, directly connecting dynamic triggering mechanisms with observational data remains challenging. One proposed failure mechanism suggests that both the amplitude and duration of cyclic fatigue caused by the passing seismic wave contribute to triggering occurrence. Here, we measure dynamic...
Authors
Nicolas DeSalvio, Andrew Barbour, Wenyuan Fan

Long-term trends in microseismicity during operational shut-ins at the Coso Geothermal Field, California Long-term trends in microseismicity during operational shut-ins at the Coso Geothermal Field, California

Pausing injection and production can lead to induced seismicity in a variety of settings, with some of the largest events occurring during these so-called shut-ins. In geothermal fields, shut-ins are periodically conducted for maintenance on wells and surface infrastructure, thereby offering recurring means of estimating stress changes in the subsurface that lead to increased seismicity...
Authors
Joanna Holmgren, J. Ole Kaven, Volker Oye

ShakeAlert® version 3: Expected performance in large earthquakes ShakeAlert® version 3: Expected performance in large earthquakes

The ShakeAlert earthquake early warning (EEW) system partners along with U.S. Geological Survey (USGS) licensed operators deliver EEW alerts to the public and trigger automated systems when a significant earthquake is expected to impact California, Oregon, or Washington. ShakeAlert’s primary goal is to provide usable warning times before the arrival of damaging shaking. EEW is most...
Authors
Jeffrey J. McGuire, Carl W. Ulberg, Angela I. Lux, Maren Bose, J.R. Andrews, Deborah Smith, B. Crowell, Jessica R. Murray, I. Henson, R. Hartog, C. Felizardo, Minh Huynh, M. Aranha, Grace Alexandra Parker, Annemarie S. Baltay Sundstrom, Mark Hunter Murray, Glenn Biasi, Stephen Guiwits, J.K. Saunders, Andrew D. Good, V. Marcelo Santillan, C.W. Scrivener, Walter M. Szeliga, Timothy I. Melbourne, Victor Kress, Robert M. de Groot, Sara K. McBride, Douglas D. Given, Richard Allen, Thomas H. Heaton, Allen L. Husker, Valerie I. Thomas, Harold Tobin, Sumant Jha, Julian Bunn

Mapping bedrock outcrops in the Sierra Nevada Mountains (California, USA) using machine learning Mapping bedrock outcrops in the Sierra Nevada Mountains (California, USA) using machine learning

Accurate, high-resolution maps of bedrock outcrops can be valuable for applications such as models of land–atmosphere interactions, mineral assessments, ecosystem mapping, and hazard mapping. The increasing availability of high-resolution imagery can be coupled with machine learning techniques to improve regional bedrock outcrop maps. In the United States, the existing 30 m U.S...
Authors
Apoorva Ramesh Shastry, Corina Cerovski-Darriau, Brian Coltin, Jonathan D. Stock

3D viscoelastic models of slip-deficit rate along the Cascadia subduction zone 3D viscoelastic models of slip-deficit rate along the Cascadia subduction zone

Interseismic deformation in the Pacific Northwest is constrained by the horizontal crustal velocity field derived from the Global Positioning System (GPS) in addition to vertical rates derived from GPS, leveling, and tide gauge measurements. Such measurements were folded in to deformation models of fault slip rates as part of the 2023 National Seismic Hazard Model (NSHM) update. Here I...
Authors
Frederick Pollitz

Haunted Summerville: Ghostly lights or earthquake lights? Haunted Summerville: Ghostly lights or earthquake lights?

Among the colorful local lore in the Charleston, South Carolina, area, are a number of ghost stories, shared not only over campfires but also in published books. Among the most well-known of the stories is the tale of the Summerville Light. Local lore holds that a strange light sometimes seen in a remote area is a lantern carried by the ghost of a local woman who once waited hours for...
Authors
Susan E. Hough

Slow slip detectability in seafloor pressure records offshore Alaska Slow slip detectability in seafloor pressure records offshore Alaska

In subduction zones worldwide, seafloor pressure data are used to observe tectonic deformation, particularly from megathrust earthquakes and slow slip events (SSEs). However, such measurements are also sensitive to oceanographic circulation-generated pressures over a range of frequencies that conflate with tectonic signals of interest. Using seafloor pressure and temperature data from...
Authors
Erik Fredrickson, Joan S. Gomberg, William Wilcock, Susan Hautala, Albert Hermann, H. Paul Johnson

Simulating human behavior under earthquake early warning Simulating human behavior under earthquake early warning

Earthquakes are a rapid-onset hazard where advance planning and learning plays a key role in mitigating injuries and death to individuals. Recent advances in earthquake detection have resulted in the development of earthquake early warning (EEW) systems. These systems can provide advance warning to predetermined geographic regions that an earthquake is in progress, which may result in...
Authors
Matthew Wood, Sara K. McBride, Xilei Zhao, Dare Baldwin, Elizabeth S. Cochran, Xiaojian Zhang, Nicolas Luco, Ruggiero Lovreglio, Tom Cova

Reply to, “Comment on ‘The 1886 Charleston, South Carolina, earthquake: Relic railroad offset reveals rupture,’ by Roger Bilham and Susan E. Hough” Reply to, “Comment on ‘The 1886 Charleston, South Carolina, earthquake: Relic railroad offset reveals rupture,’ by Roger Bilham and Susan E. Hough”

We welcome this opportunity to respond to Pratt et al. (2024) (hereinafter P24). Bilham and Hough (2023) proposed a “first-cut” elastic deformation model for the 1886 earthquake, a quantitative source model constrained by identified coseismic constraints. A key observation was the measurement of a lateral offset of a railroad line south of Summerville, leading to a model with...
Authors
Roger Bilham, Susan E. Hough
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