Publications
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Converted-wave reverse time migration imaging in subduction zone settings
We use a newly developed 2-D elastic reverse time migration (RTM) imaging algorithm based on the Helmholtz decomposition to test approaches for imaging the descending slab in subduction zone regions using local earthquake sources. Our elastic RTM method is designed to reconstruct incident and scattered wavefields at depth, isolate constituent P- and S-wave components via Helmholtz decomposition, a
Authors
Leah Langer, Fred Pollitz, Jeffrey McGuire
Towards improved code-based performance objectives for liquefaction hazard analysis
Ground failure due to liquefaction in loose sand deposits poses substantial risks to the built environment, and has caused significant damage in past earthquakes to a wide range of infrastructure. Advances in liquefaction hazard analysis in practice have largely stagnated in recent years; the state of practice remains rooted in simplified procedures that ignore considerable uncertainties in liquef
Authors
Andrew James Makdisi, Steven L. Kramer
Comparison of co-recorded analog and digital systems for characterization of responses and uncertainties
One of the most prominent challenges related to legacy seismic data is determining how these data can be appropriately used in modern research applications. The wide variety of instrumentation used in the analog era, the format of recording on paper wrapped around a helicorder drum, and limited metadata information introduces ambiguities that are not typical of modern digital data. Therefore, tech
Authors
Thomas A. Lee, Adam T. Ringler, Robert E. Anthony, Miaki Ishii
The relation between decadal droughts and eruptions of Steamboat Geyser in Yellowstone National Park, USA
In the past century, most eruptions of Steamboat Geyser in Yellowstone National Park's Norris Geyser Basin were mainly clustered in three episodes: 1961–1969, 1982–1984, and ongoing since 2018. These eruptive episodes resulted in extensive disturbance to surrounding trees. To characterize tree response over time as an indicator of geyser activity adjustments to climate variability, aerial and grou
Authors
Shaul Hurwitz, John C. King, Gregory T. Pederson, Mara H. Reed, Lauren N Harrison, Jefferson Hungerford, R. Greg Vaughan, Michael Manga
Accuracy of finite fault slip estimates in subduction zone regions with topographic Green's functions and seafloor geodesy
Until recently, the lack of seafloor geodetic instrumentation and the use of unrealistically simple, half-space based forward models have resulted in poor resolution of near-trench slip in subduction zone settings. Here, we use a synthetic framework to investigate the impact of topography and geodetic data distribution on coseismic slip estimates in various subduction zone settings. We calculate s
Authors
Leah Langer, Théa Ragon
Alerting the globe of consequential earthquakes
The primary ingredients on the hazard side of the equation include the rapid characterization of the earthquake source and quantifying the spatial distribution of the shaking, plus any secondary hazards an earthquake may have triggered. On the earthquake impact side, loss calculations require the aforementioned hazard assessments—and their uncertainties—as input, plus the quantification of the exp
Authors
David J. Wald
Distribution of large boulders on the deposit of the West Salt Creek rock avalanche, western Colorado
On May 25, 2014, a 54.5-million cubic meter rock avalanche in the West Salt Creek valley, Mesa County, Colorado, traveled 4.6 kilometers, leaving a deposit that covers about 2.2 square kilometers. To check the particle-size distribution of the deposit for information about the high mobility of the avalanche, we estimated boulder distribution density for the entire deposit by counting 1-meter (m) o
Authors
Adrian C. Lewis, Rex L. Baum, Jeffrey A. Coe
Debris-flow process controls on steepland morphology in the San Gabriel Mountains, California
Steep landscapes evolve largely by debris flows, in addition to fluvial and hillslope processes. Abundant field observations document that debris flows incise valley bottoms and transport substantial sediment volumes, yet their contributions to steepland morphology remain uncertain. This has, in turn, limited the development of debris-flow incision rate formulations that produce morphology consist
Authors
William Struble, Luke A. McGuire, Scott W. McCoy, Katherine R. Barnhart, Odin Marc
Slip deficit rates on southern Cascadia faults resolved with viscoelastic earthquake cycle modeling of geodetic deformation
The fore‐arc of the southern Cascadia subduction zone (CSZ), north of the Mendocino triple junction (MTJ), is home to a network of Quaternary‐active crustal faults that accumulate strain due to the interaction of the North American, Juan de Fuca (Gorda), and Pacific plates. These faults, including the Little Salmon and Mad River fault (LSF and MRF) zones, are located near the most populated parts
Authors
Kathryn Zerbe Materna, Jessica R. Murray, Fred Pollitz, Jason R. Patton
Postfire hydrologic response along the central California (USA) coast: Insights for the emergency assessment of postfire debris-flow hazards
The steep, tectonically active terrain along the Central California (USA) coast is well known to produce deadly and destructive debris flows. However, the extent to which fire affects debris-flow susceptibility in this region is an open question. We documented the occurrence of postfire debris floods and flows following the landfall of a storm that delivered intense rainfall across multiple burn a
Authors
Matthew A. Thomas, Jason W. Kean, Scott W. McCoy, Donald N. Lindsay, Jaime Kostelnik, David B. Cavagnaro, Francis K. Rengers, Amy E. East, Jonathan Schwartz, Douglas P. Smith, Brian D. Collins
A detailed view of the 2020-2023 southwestern Puerto Rico seismic sequence with deep learning
The 2020–2023 southwestern Puerto Rico seismic sequence, still ongoing in 2023, is remarkable for its multiple‐fault rupture complexity and elevated aftershock productivity. We applied an automatic workflow to continuous data from 43 seismic stations in Puerto Rico to build an enhanced earthquake catalog with ∼180,000 events for the 3+ yr sequence from 28 December 2019 to 1 January 2023. This work
Authors
Clara Yoon, Elizabeth S. Cochran, Elizabeth A. Vanacore, Victor Huerfano, Gisela Báez-Sánchez, John D. Wilding, Jonathan D. Smith
Earthquake scenarios for Quito, Ecuador; Cali, Colombia; and Santiago De Los Caballeros, Dominican Republic
Earthquake risk associated with Quito, Ecuador; Cali, Colombia; and Santiago de los Caballeros, Dominican Republic is examined by generating a set of hypothetical earthquake scenarios considering seismic sources, recent seismicity, and major historical earthquakes recorded in the vicinity. In this study, particular focus is given to the development of earthquake scenarios for use in emergency plan
Authors
Robert Edward Chase, Kishor S. Jaiswal, Alejandro Calderon, Hugo Yepes, Loren Goddard, Catalina Yepes-Estrada