Publications
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Quaternary extensional growth folding beneath Reno, Nevada, imaged by urban seismic profiling
We characterize shallow subsurface faulting and basin structure along a transect through heavily urbanized Reno, Nevada, with high‐resolution seismic reflection imaging. The 6.8 km of P‐wave data image the subsurface to approximately 800 m depth and delineate two subbasins and basin uplift that are consistent with structure previously inferred from gravity modeling in this region of the northern W
Authors
William J. Stephenson, Roxy N. Frary, John Louie, Jackson K. Odum
Photometric properties of Mars soils analogs
We have measured the bidirectional reflectance of analogs of dry, wet, and frozen Martian soils over a wide range of phase angles in the visible spectral range. All samples were produced from two geologic samples: the standard JSC Mars-1 soil simulant and Hawaiian basaltic sand. In a first step, experiments were conducted with the dry samples to investigate the effects of surface texture. Comparis
Authors
A. Pommerol, N. Thomas, B. Jost, P. Beck, C. Okubo, A. S. McEwen
Runoff-generated debris flows: observations and modeling of surge initiation, magnitude, and frequency
Runoff during intense rainstorms plays a major role in generating debris flows in many alpine areas and burned steeplands. Yet compared to debris flow initiation from shallow landslides, the mechanics by which runoff generates a debris flow are less understood. To better understand debris flow initiation by surface water runoff, we monitored flow stage and rainfall associated with debris flows in
Authors
Jason W. Kean, Scott W. McCoy, Gregory E. Tucker, Dennis M. Staley, Jeffrey A. Coe
Rupture complexity of the Mw 8.3 sea of okhotsk earthquake: Rapid triggering of complementary earthquakes?
We derive a finite slip model for the 2013 Mw 8.3 Sea of Okhotsk Earthquake (Z = 610 km) by inverting calibrated teleseismic P waveforms. The inversion shows that the earthquake ruptured on a 10° dipping rectangular fault zone (140 km × 50 km) and evolved into a sequence of four large sub-events (E1–E4) with an average rupture speed of 4.0 km/s. The rupture process can be divided into two main sta
Authors
Shengji Wei, Don Helmberger, Zhongwen Zhan, Robert Graves
Meeting of the Central and Eastern U.S. (CEUS) Earthquake Hazards Program October 28–29, 2009
On October 28th and 29th, 2009, the U.S. Geological Survey Earthquake Hazards Program held a meeting of Central and Eastern United States investigators and interested parties in Memphis, Tennessee. The purpose of the meeting was to bring together the Central and Eastern United States earthquake-hazards community to present and discuss recent research results, to promote communication and collabora
Authors
Martitia Tuttle, Oliver Boyd, Natasha McCallister
Natural Hazards Science at the U.S. Geological Survey
The mission of the USGS in natural hazards is to develop and apply hazard science to help protect the safety, security, and economic well-being of the Nation. The costs and consequences of natural hazards can be enormous, and each year more people and infrastructure are at risk. The USGS conducts hazard research and works closely with stakeholders and cooperators to inform a broad range of plannin
Authors
Suzanne C. Perry, Lucile M. Jones, Robert R. Holmes
Report of geomagnetic pulsation indices for space weather applications
The phenomenon of ultra-low frequency geomagnetic pulsations was first observed in the ground-based measurements of the 1859 Carrington Event and has been studied for over 100 years. Pulsation frequency is considered to be “ultra” low when it is lower than the natural frequencies of the plasma, such as the ion gyrofrequency. Ultra-low frequency pulsations are considered a source of noise in some g
Authors
Z. Xu, Jennifer L. Gannon, Erin J. Rigler
Caveats on tomographic images
Geological and geodynamic models of the mantle often rely on joint interpretations of published seismic tomography images and petrological/geochemical data. This approach tends to neglect the fundamental limitations of, and uncertainties in, seismic tomography results. These limitations and uncertainties involve theory, correcting for the crust, the lack of rays throughout much of the mantle, the
Authors
Gillian R. Foulger, Giuliano F. Panza, Irina M. Artemieva, Ian D. Bastow, Fabio Cammarano, John R. Evans, Warren B. Hamilton, Bruce R. Julian, Michele Lustrino, Hans Thybo
Permanently enhanced dynamic triggering probabilities as evidenced by two M ≥ 7.5 earthquakes
The 2012 M7.7 Haida Gwaii earthquake radiated waves that likely dynamically triggered the 2013M7.5 Craig earthquake, setting two precedents. First, the triggered earthquake is the largest dynamically triggered shear failure event documented to date. Second, the events highlight a connection between geologic structure, sedimentary troughs that act as waveguides, and triggering probability. The Haid
Authors
Joan S. Gomberg
Obtaining changes in calibration-coil to seismometer output constants using sine waves
The midband sensitivity of a broadband seismometer is one of the most commonly used parameters from station metadata. Thus, it is critical for station operators to robustly estimate this quantity with a high degree of accuracy. We develop an in situ method for estimating changes in sensitivity using sine‐wave calibrations, assuming the calibration coil and its drive are stable over time and temper
Authors
Adam T. Ringler, Charles R. Hutt, Lind S. Gee, Leo D. Sandoval, David C. Wilson
Semiautomated tremor detection using a combined cross-correlation and neural network approach
Despite observations of tectonic tremor in many locations around the globe, the emergent phase arrivals, low‒amplitude waveforms, and variable event durations make automatic detection a nontrivial task. In this study, we employ a new method to identify tremor in large data sets using a semiautomated technique. The method first reduces the data volume with an envelope cross‒correlation technique, f
Authors
Tobias Horstmann, Rebecca M. Harrington, Elizabeth S. Cochran
Clustering of velocities in a GPS network spanning the Sierra Nevada Block, the northern Walker Lane Belt, and the Central Nevada Seismic Belt, California-Nevada
The deformation across the Sierra Nevada Block, the Walker Lane Belt, and the Central Nevada Seismic Belt (CNSB) between 38.5°N and 40.5°N has been analyzed by clustering GPS velocities to identify coherent blocks. Cluster analysis determines the number of clusters required and assigns the GPS stations to the proper clusters. The clusters are shown on a fault map by symbols located at the position
Authors
James C. Savage, Robert W. Simpson