Publications
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An overview of the National Earthquake Information Center acquisition software system, Edge/Continuous Waveform Buffer An overview of the National Earthquake Information Center acquisition software system, Edge/Continuous Waveform Buffer
This document provides an overview of the capabilities, design, and use cases of the data acquisition and archiving subsystem at the U.S. Geological Survey National Earthquake Information Center. The Edge and Continuous Waveform Buffer software supports the National Earthquake Information Center’s worldwide earthquake monitoring mission in direct station data acquisition, data import...
Authors
John M. Patton, David C. Ketchum, Michelle R. Guy
Introduction to the focus section on the 2015 Gorkha, Nepal, earthquake Introduction to the focus section on the 2015 Gorkha, Nepal, earthquake
It has long been recognized that Nepal faces high earthquake hazard, with the most recent large (Mw>7.5) events in 1833 and 1934. When the 25 April 2015Mw 7.8 Gorkha earthquake struck, it appeared initially to be a realization of worst fears. In spite of its large magnitude and proximity to the densely populated Kathmandu valley, however, the level of damage was lower than anticipated...
Authors
Susan E. Hough
Ground motions from the 2015Mw 7.8 Gorkha, Nepal, earthquake constrained by a detailed assessment of macroseismic data Ground motions from the 2015Mw 7.8 Gorkha, Nepal, earthquake constrained by a detailed assessment of macroseismic data
To augment limited instrumental recordings of the Mw 7.8 Gorkha, Nepal, earthquake on 25 April 2015 (Nepali calendar: 12 Baisakh 2072, Bikram Samvat), we collected 3831 detailed media and first-person accounts of macroseismic effects that include sufficiently detailed information to assign intensities. The resulting intensity map reveals the distribution of shaking within and outside of...
Authors
Stacey Martin, Susan E. Hough, Charleen Hung
Limited role for thermal erosion by turbulent lava in proximal Athabasca Valles, Mars Limited role for thermal erosion by turbulent lava in proximal Athabasca Valles, Mars
The Athabasca Valles flood lava is among the most recent (
Authors
Vincenzo Cataldo, David A. Williams, Colin M. Dundas, Laszlo P. Keszthelyi
Reactivated faulting near Cushing, Oklahoma: Increased potential for a triggered earthquake in an area of United States strategic infrastructure Reactivated faulting near Cushing, Oklahoma: Increased potential for a triggered earthquake in an area of United States strategic infrastructure
In October 2014 two moderate-sized earthquakes (Mw 4.0 and 4.3) struck south of Cushing, Oklahoma, below the largest crude oil storage facility in the world. Combined analysis of the spatial distribution of earthquakes and regional moment tensor focal mechanisms indicate reactivation of a subsurface unnamed and unmapped left-lateral strike-slip fault. Coulomb failure stress change...
Authors
Daniel E. McNamara, Gavin P. Hayes, Harley M. Benz, Robert Williams, Nicole D McMahon, R.C. Aster, Austin F. Holland, T Sickbert, Robert B. Herrmann, Richard W. Briggs, Gregory M. Smoczyk, Eric Bergman, Paul S. Earle
Validation of meter-scale surface faulting offset measurements from high-resolution topographic data Validation of meter-scale surface faulting offset measurements from high-resolution topographic data
Studies of active fault zones have flourished with the availability of high-resolution topographic data, particularly where airborne light detection and ranging (lidar) and structure from motion (SfM) data sets provide a means to remotely analyze submeter-scale fault geomorphology. To determine surface offset at a point along a strike-slip earthquake rupture, geomorphic features (e.g...
Authors
Barrett Salisbury, D.E. Haddad, T. K. Rockwell, R. Arrowsmith, C. Madugo, O. Zielke, Katherine M. Scharer
A random-walk algorithm for modeling lithospheric density and the role of body forces in the evolution of the Midcontinent Rift A random-walk algorithm for modeling lithospheric density and the role of body forces in the evolution of the Midcontinent Rift
This paper develops a Monte Carlo algorithm for extracting three-dimensional lithospheric density models from geophysical data. Empirical scaling relationships between velocity and density create a 3D starting density model, which is then iteratively refined until it reproduces observed gravity and topography. This approach permits deviations from uniform crustal velocity-density scaling...
Authors
William Brower Levandowski, Oliver S. Boyd, Richard W. Briggs, Ryan D. Gold
Modeling the development of martian sublimation thermokarst landforms Modeling the development of martian sublimation thermokarst landforms
Sublimation-thermokarst landforms result from collapse of the surface when ice is lost from the subsurface. On Mars, scalloped landforms with scales of decameters to kilometers are observed in the mid-latitudes and considered likely thermokarst features. We describe a landscape evolution model that couples diffusive mass movement and subsurface ice loss due to sublimation. Over periods...
Authors
Colin M. Dundas, Shane Byrne, Alfred S. McEwen
Using a modified time-reverse imaging technique to locate low-frequency earthquakes on the San Andreas Fault near Cholame, California Using a modified time-reverse imaging technique to locate low-frequency earthquakes on the San Andreas Fault near Cholame, California
We present a new method to locate low-frequency earthquakes (LFEs) within tectonic tremor episodes based on time-reverse imaging techniques. The modified time-reverse imaging technique presented here is the first method that locates individual LFEs within tremor episodes within 5 km uncertainty without relying on high-amplitude P-wave arrivals and that produces similar hypocentral...
Authors
Tobias Horstmann, Rebecca M. Harrington, Elizabeth S. Cochran
Identifying block structure in the Pacific Northwest, USA Identifying block structure in the Pacific Northwest, USA
We have identified block structure in the Pacific Northwest (west of 116°W between 38°N and 49°N) by clustering GPS stations so that the same Euler vector approximates the velocity of each station in a cluster. Given the total number k of clusters desired, the clustering procedure finds the best assignment of stations to clusters. Clustering is calculated for k= 2 to 14. In geographic...
Authors
James C. Savage, Ray E. Wells
Deposition, exhumation, and paleoclimate of an ancient lake deposit, Gale crater, Mars Deposition, exhumation, and paleoclimate of an ancient lake deposit, Gale crater, Mars
The landforms of northern Gale crater on Mars expose thick sequences of sedimentary rocks. Based on images obtained by the Curiosity rover, we interpret these outcrops as evidence for past fluvial, deltaic, and lacustrine environments. Degradation of the crater wall and rim probably supplied these sediments, which advanced inward from the wall, infilling both the crater and an internal...
Authors
J.P. Grotzinger, S. Gupta, M. C. Malin, D. M. Rubin, J. Schieber, K. Siebach, D.Y. Sumner, K.M. Stack, A.R. Vasavada, R.E. Arvidson, F. Calef, Lauren A. Edgar, W. F. Fischer, J.A. Grant, J.L. Griffes, L.C. Kah, M.P. Lamb, K.W. Lewis, N. Mangold, M.E. Minitti, M.C. Palucis, M. Rice, R.M.E. Williams, R.A. Yingst, D. Blake, D. Blaney, P. Conrad, J.A. Crisp, W. E. Dietrich, G. Dromart, K.S. Edgett, R.C. Ewing, R. Gellert, J.A. Hurowitz, G. Kocurek, P.G. Mahaffy, M.J. McBride, S. M. McLennan, M.A. Mischna, D. Ming, R.E. Milliken, H. Newsom, D. Oehler, T. J. Parker, D. Vaniman, R. C. Wiens, S. A. Wilson
Borehole strainmeter measurements spanning the 2014, Mw6.0 South Napa Earthquake, California: The effect from instrument calibration Borehole strainmeter measurements spanning the 2014, Mw6.0 South Napa Earthquake, California: The effect from instrument calibration
The 24 August 2014 Mw6.0 South Napa, California earthquake produced significant offsets on 12 borehole strainmeters in the San Francisco Bay area. These strainmeters are located between 24 and 80 km from the source and the observed offsets ranged up to 400 parts-per-billion (ppb), which exceeds their nominal precision by a factor of 100. However, the observed offsets of tidally...
Authors
John O. Langbein