Publications
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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 Hough
Thicknesses of lava flows in satellite images: Comparison of layered mare units with terrestrial analogs Thicknesses of lava flows in satellite images: Comparison of layered mare units with terrestrial analogs
Recent advances in satellite imaging technology have greatly improved our observations of planetary surfaces. The Lunar Reconnaissance Orbiter (LRO) Narrow Angle Camera (NAC) records images with resolutions on average of 0.5 m per pixel, resolving meter scale features on the surface of the Moon. NAC images have revealed layered deposits, interpreted to be sequences of mare basalt flows...
Authors
M. Rumpf, Heidi Needham, Sarah Fagents
SCEC/USGS Community Stress Drop Validation Study: How spectral fitting approaches influence measured source parameters SCEC/USGS Community Stress Drop Validation Study: How spectral fitting approaches influence measured source parameters
Spectral source parameters used to estimate an earthquake’s stress drop (Δσ) can vary significantly across measurement approaches. The Statewide California Earthquake Center/U.S. Geological Survey Community Stress-Drop Validation Study was initiated to compare source parameter estimates, focusing initially on a dataset from the 2019 Ridgecrest earthquake sequence. As part of that...
Authors
Elizabeth Cochran, Annemarie Baltay Sundstrom, Shanna Chu, Rachel E. Abercrombie, Dino Bindi, X. Chen, Grace Parker, Colin Pennington, Peter Shearer, Daniel Trugman
Late Amazonian ice near Athabasca Valles, Mars: Recent megaflood or climate change? Late Amazonian ice near Athabasca Valles, Mars: Recent megaflood or climate change?
The Athabasca Valles outflow channel system is among the youngest such channels on Mars, with the Athabasca Valles flood lava (AVFL) covering the channel floor and reaching far beyond. Volcanic rootless cones on the AVFL indicate the presence of H2O in the shallow subsurface at the time of lava emplacement. However, Athabasca Valles are near the equator, where ice would rapidly sublime...
Authors
Colin M. Dundas, Laszlo P. Keszthelyi, Kaj Williams
Characterizing directivity in small (M 2.4-5) aftershocks of the Ridgecrest sequence Characterizing directivity in small (M 2.4-5) aftershocks of the Ridgecrest sequence
Directivity, or the focusing of energy along the direction of an earthquake rupture, is a common property of earthquakes of all sizes and can cause increased hazard due to azimuthally dependent ground‐motion amplification. For small earthquakes, the effects of directivity are generally less pronounced due to reduced rupture size, yet the directivity in small events can bias source...
Authors
Shanna Chu, Annemarie Baltay Sundstrom, Rachel E. Abercrombie
Global patterns of coseismic landslide runout mobility differ from aseismic landslide trends Global patterns of coseismic landslide runout mobility differ from aseismic landslide trends
Coseismic landslides significantly contribute to human and economic losses during and immediately following earthquakes, yet very little data on the runout of such landslides exist. While well-established behavior of aseismic (e.g., hydrologically triggered) landslide runout mobility suggests strong correlation between landslide size and mobility, limited studies of coseismic landslide...
Authors
Alex Grant, Natalie Culhane
Smectite-rich horizons in Inceptisols trigger shallow landslides in tropical granitic terranes Smectite-rich horizons in Inceptisols trigger shallow landslides in tropical granitic terranes
Puerto Rico was affected by >70,000 landslides in the wake of 2017 Hurricane Maria, and landslide prevalence was especially high in the Utuado region in the Cordillera Central. Landslide density was highest where soil parent material is granodiorite; landslide slip surfaces tended to be shallow (
Authors
Peter C. Ryan, D. Mahmud, K. Derenoncourt, L. Nerbonne, I. Perez-Martin, J. Reyes Collovati, M. Junaid, Corina Cerovski-Darriau
Distinguishing natural sources from anthropogenic events in seismic data Distinguishing natural sources from anthropogenic events in seismic data
As seismic data are increasingly used to investigate a diverse range of subsurface phenomena beyond regular fast-rupturing earthquakes (Peng and Gomberg, 2010; Beroza and Ide, 2011), it is important to acknowledge that human-generated ground vibrations may be mistaken for naturally generated subsurface processes (Larose et al., 2015; Li et al., 2018). Correct discrimination of natural...
Authors
Sean Maher, Margaret Glasgow, Elizabeth Cochran, Zhigang Peng
The Europa Imaging System (EIS) investigation The Europa Imaging System (EIS) investigation
The Europa Imaging System (EIS) consists of a Narrow-Angle Camera (NAC) and a Wide-Angle Camera (WAC) that are designed to work together to address high-priority science objectives regarding Europa’s geology, composition, and the nature of its ice shell. EIS accommodates variable geometry and illumination during rapid, low-altitude flybys with both framing and pushbroom imaging...
Authors
E.P. Turtle, A.S. McEwen, G.W. Patterson, C. Ernst, C.M. Elder, K.A. Slack, S.E. Hawkins, J. McDermott, H. Meyer, R. DeMajistre, R. Espiritu, H. Seifert, J. Niewola, Michael Bland, M.K. Becker, J. Centurelli, G.C. Collins, P. Corlies, H. Darlington, I. Daubar, C. Derr, C. Detelich, E. Donald, W. Edens, L. Fletcher, C. Gardner, F. Graham, C.J. Hansen, C. Haslebacher, A.G. Hayes, D. Humm, T.A. Hurford, Randolph Kirk, N. Kutsop, W.J. Lees, D. Lewis, S. London, A. Magner, M.A. Mills, A.C. Barr Mlinar, F. Morgan, F. Nimmo, A. Ocasio Milanes, S. Osterman, C.B. Phillips, A. Pommerol, L. Prockter, L.C. Quick, G. Robbins, J.M. Soderblom, B.A. Stewart, A. Stickle, S.S. Sutton, N. Thomas, I. Torres, O.J. Tucker, R.B. Van Auken, K.A. Wilk
Using the horizontal-to-vertical spectral ratio method to estimate thickness of the Barry Arm landslide, Prince William Sound, Alaska Using the horizontal-to-vertical spectral ratio method to estimate thickness of the Barry Arm landslide, Prince William Sound, Alaska
Conducting detailed investigations of large landslides is difficult, especially in the subsurface, largely due to environmental factors such as steep slopes, difficult access, and numerous objective hazards. These factors have made it challenging to accurately estimate the depth to the failure surface of the Barry Arm landslide, a large (roughly 108 cubic meters), deep-seated bedrock...
Authors
Andrew Collins, Kate Allstadt, Dennis Staley
Constraining large magnitude event source and path effects using ground motion simulations Constraining large magnitude event source and path effects using ground motion simulations
The purpose of this study is to use ground motion simulations to investigate ways in which source and path effects for large magnitude events can be represented in non-ergodic GMMs. While we initially developed computation techniques using CyberShake simulations, the range of magnitudes and source-site combinations is not adequate to replicate what is observed empirically. We therefore...
Authors
Xiaofeng Meng, Robert Graves, Christine Goulet
Reconciling bias in moderate magnitude earthquake ground motions predicted by numerical simulations Reconciling bias in moderate magnitude earthquake ground motions predicted by numerical simulations
Recent studies found a significant underprediction in ground motion intensity measures for finite-fault simulations of moderate magnitude events in southern California relative to established ground motion models. This study aims to understand the source(s) of this bias by evaluating ground motion residuals. For this, simulations have been performed for a total of 27 well-recorded...
Authors
K. C. Sajan, Chukwuebuka C. Nweke, Jonathon P. Stewart, Robert Graves