Publications
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On the scale-dependence of fault surface roughness
Defining roughness as the ratio of height to length, the standard approach to characterize amplitudes of single fault, joint and fracture surfaces is to measure average height as a function of profile length. Empirically, this roughness depends strongly on scale. The ratio is approximately 0.01 at a few mm but 10× smaller at a few tens of meters. Surfaces are rougher at small scales. However, thes
Authors
Nicholas M. Beeler
Solid Earth–atmosphere interaction forces during the 15 January 2022 Tonga eruption
Rapid venting of volcanic material during the 15 January 2022 Tonga eruption generated impulsive downward reaction forces on the Earth of ~2.0 × 1013 N that radiated seismic waves observed throughout the planet, with ~25 s source bursts persisting for ~4.5 hours. The force time history is determined by analysis of teleseismic P waves and Rayleigh waves with periods approximately <50 s, providing i
Authors
Ricardo Garza-Giron, Thorne Lay, Fred Pollitz, Hiroo Kanamori, Luis Rivera
Comparison of ventifact orientations and recent wind direction indicators on the floor of Jezero crater, Mars
Wind-abraded rocks and aeolian bedforms have been observed at the Mars 2020 Perseverance landing site, providing evidence for recent and older wind directions. This study reports orientations of aeolian features measured in Perseverance images to infer formative wind directions. It compares these measurements with orbital observations, climate model predictions, and wind data acquired by the Mars
Authors
Kenneth E. Herkenhoff, Rob Sullivan, Claire E Newman, Gerhard Paar, Mariah Baker, Daniel Viudez-Moreiras, James W. Ashley, Andreas Bechtold, Jorge I Nunez
Ground motion selection for nonlinear response history analyses of concrete dams
Evaluating the seismic performance of a 3D concrete dam using nonlinear response history analysis (NLRHA) requires three orthogonal components of ground acceleration histories, or ground motions (GMs) for brevity. Although much progress has been made for the topic of ground motion selection and modification (GMSM) in the context of multistory buildings, NLRHA of dams requires at least two addition
Authors
N. Simon Kwong
Inclusive lunar exploration: Lunar Surface Science Workshop virtual session 13
This report reviews and presents findings from the Lunar Surface Science Workshop Virtual Session 13: Inclusive Lunar Exploration. The report consists of a brief introduction to the workshop, followed by summaries of the six workshop sessions, and a synthesis section discussing seven key findings.
Authors
Parvathy Prem, Kristen A. Bennett
Fracture-mesh faulting in the swarm-like 2020 Maacama sequence revealed by high-precision earthquake detection, location, and focal mechanisms
In August of 2020, an earthquake sequence initiated within the Maacama fault zone in northern California, raising questions about its relationship with the larger-scale fault. To investigate the faulting geometry and its implications for physical processes driving seismicity, we applied an integrated, multi-faceted seismic analysis including waveform-correlation-based event detection, relative rel
Authors
David R. Shelly, Robert John Skoumal, Jeanne L. Hardebeck
Using seismic noise correlation to determine the shallow velocity structure of the Seattle basin, Washington
Cross-correlation waveforms of seismic noise in the Seattle basin, Washington, were analyzed to determine the group velocities of surface waves and constrain the shear-wave velocity (VS) for depths less than about 2 kilometers (km). Twenty broadband seismometers were deployed for about 3 weeks in three dense arrays separated by about 5 km, with minimum intra-array station spacing of about 0.5 km.
Authors
Arthur Frankel, Paul Bodin
Optimizing satellite resources for the global assessment and mitigation of volcanic hazards—Suggestions from the USGS Powell Center Volcano Remote Sensing Working Group
A significant number of the world’s approximately 1,400 subaerial volcanoes with Holocene eruptions are unmonitored by ground-based sensors yet constitute a potential hazard to nearby residents and infrastructure, as well as air travel and global commerce. Data from an international constellation of more than 60 current satellite instruments provide a cost-effective means of tracking activity and
Authors
M. E. Pritchard, M. Poland, K. Reath, B. Andrews, M. Bagnardi, J. Biggs, S. Carn, D. Coppola, S.K. Ebmeier, M.A. Furtney, T. Girona, J. Griswold, T. Lopez, P. Lundgren, S. Ogburn, M. Pavolonis, E. Rumpf, G. Vaughan, C. Wauthier, R. Wessels, R. Wright, K.R. Anderson, M.G. Bato, A. Roman
Seismic multi-hazard and impact estimation via causal inference from satellite imagery
Rapid post-earthquake reconnaissance is important for emergency responses and rehabilitation by providing accurate and timely information about secondary hazards and impacts, including landslide, liquefaction, and building damage. Despite the extensive collection of geospatial data and satellite images, existing physics-based and data-driven methods suffer from low estimation performance due to th
Authors
Susu Xu, Joshua Dimasaka, David J. Wald, Hae Young Noh
Spatial and temporal distribution of sinuous ridges in southeastern Terra Sabaea and the northern region of Hellas Planitia, Mars
Sinuous ridges are an important yet understudied component of Mars' hydrologic history. We have produced a map of sinuous ridges, valleys and channels, and tectonic ridges across southeastern Terra Sabaea and into northern Hellas Planitia (10°-45° S, 35°-80° E) using a CTX mosaic. Although we mapped different types of ridges and negative relief features, the focus of this paper are the sinuous rid
Authors
Amber Gullikson, Ryan Anderson, Rebecca M.E. Williams
A large new crater exposes the limits of water ice on Mars
Water ice in the Martian mid-latitudes has advanced and retreated in response to variations in the planet's orbit, obliquity, and climate. A 150 m-diameter new impact crater near 35°N provides the lowest-latitude impact exposure of subsurface ice on Mars. This is the largest known ice-exposing crater and provides key constraints on Martian climate history. This crater indicates a regional, relativ
Authors
Colin M. Dundas, Michael T. Mellon, Liliya V Posiolova, Katarina Miljkovic, Gareth S Collins, Livio L. Tornabene, Vidhya Ganesh Rangarajan, Matthew P. Golombek, Nicholas H. Warner, Ingrid J. Daubar, Shane Byrne, Alfred S. McEwen, Kimberly D. Seelos, Donna Viola, Ali M Bramson, Gunnar Speth
Estimates of k0 and effects on ground motions in the San Francisco Bay area
Ground‐motion studies are a key component of seismic hazard analyses and often rely on information of the source, path, and site. Extensive research has been done on each of these parameters; however, site‐specific studies are of particular interest to seismic hazard studies, especially in the field of earthquake engineering, as near‐site conditions can have a significant impact on the resulting g
Authors
Tara Nye, Valerie J. Sahakian, Elias King, Annemarie S. Baltay, Alexis Klimasewski