Publications
Filter Total Items: 1857
Earthquake forewarning in the Cascadia region
This report, prepared for the National Earthquake Prediction Evaluation Council (NEPEC), is intended as a step toward improving communications about earthquake hazards between information providers and users who coordinate emergency-response activities in the Cascadia region of the Pacific Northwest. NEPEC charged a subcommittee of scientists with writing this report about forewarnings of increase
Authors
Joan S. Gomberg, Brian F. Atwater, Nicholas M. Beeler, Paul Bodin, Earl Davis, Arthur Frankel, Gavin P. Hayes, Laura McConnell, Tim Melbourne, David H. Oppenheimer, John G. Parrish, Evelyn A. Roeloffs, Gary D. Rogers, Brian L. Sherrod, John Vidale, Timothy J. Walsh, Craig S. Weaver, Paul M. Whitmore
ShakeNet: a portable wireless sensor network for instrumenting large civil structures
We report our findings from a U.S. Geological Survey (USGS) National Earthquake Hazards Reduction Program-funded project to develop and test a wireless, portable, strong-motion network of up to 40 triaxial accelerometers for structural health monitoring. The overall goal of the project was to record ambient vibrations for several days from USGS-instrumented structures. Structural health monitoring
Authors
Monica D. Kohler, Shuai Hao, Nilesh Mishra, Ramesh Govindan, Robert Nigbor
Holocene geologic slip rate for the Banning strand of the southern San Andreas Fault, southern California
Northwest directed slip from the southern San Andreas Fault is transferred to the Mission Creek, Banning, and Garnet Hill fault strands in the northwestern Coachella Valley. How slip is partitioned between these three faults is critical to southern California seismic hazard estimates but is poorly understood. In this paper, we report the first slip rate measured for the Banning fault strand. We co
Authors
Peter O. Gold, Whitney M. Behr, Dylan Rood, Warren D. Sharp, Thomas Rockwell, Katherine J. Kendrick, Aaron Salin
Myths and facts on wastewater injection, hydraulic fracturing, enhanced oil recovery, and induced seismicity
The central United States has undergone a dramatic increase in seismicity over the past 6 years (Fig. 1), rising from an average of 24 M≥3 earthquakes per year in the years 1973–2008 to an average of 193 M≥3 earthquakes in 2009–2014, with 688 occurring in 2014 alone. Multiple damaging earthquakes have occurred during this increase including the 2011 M 5.6 Prague, Oklahoma, earthquake; the 2011 M 5
Authors
Justin L. Rubinstein, Alireza Babaie Mahani
Electrical properties of methane hydrate + sediment mixtures
Knowledge of the electrical properties of multicomponent systems with gas hydrate, sediments, and pore water is needed to help relate electromagnetic (EM) measurements to specific gas hydrate concentration and distribution patterns in nature. Toward this goal, we built a pressure cell capable of measuring in situ electrical properties of multicomponent systems such that the effects of individual c
Authors
Wyatt L. Du Frane, Laura A. Stern, Steven Constable, Karen A. Weitemeyer, Megan M Smith, Jeffery J. Roberts
Larger aftershocks happen farther away: nonseparability of magnitude and spatial distributions of aftershocks
Aftershocks may be driven by stress concentrations left by the main shock rupture or by elastic stress transfer to adjacent fault sections or strands. Aftershocks that occur within the initial rupture may be limited in size, because the scale of the stress concentrations should be smaller than the primary rupture itself. On the other hand, aftershocks that occur on adjacent fault segments outside
Authors
Nicholas van der Elst, Bruce E. Shaw
Pore-pressure sensitivities to dynamic strains: observations in active tectonic regions
Triggered seismicity arising from dynamic stresses is often explained by the Mohr-Coulomb failure criterion, where elevated pore pressures reduce the effective strength of faults in fluid-saturated rock. The seismic response of a fluid-rock system naturally depends on its hydro-mechanical properties, but accurately assessing how pore-fluid pressure responds to applied stress over large scales in s
Authors
Andrew J. Barbour
Decay of S‐wave amplitudes with distance for earthquakes in the Charlevoix, Quebec, area: Effects of radiation pattern and directivity
The decay of the Fourier spectral amplitudes of S waves over distances of 10–80 km near Charlevoix, Quebec, was determined using waveforms from seven earthquakes with MN 3.3–5.4. The S‐wave spectral amplitudes were corrected for site response and source amplitude by normalizing the coda‐wave spectrum at a fixed time after the origin time. The amplitude decay with distance was found to be less stee
Authors
Arthur Frankel
Southern San Andreas Fault seismicity is consistent with the Gutenberg-Richter magnitude-frequency distribution
The magnitudes of any collection of earthquakes nucleating in a region are generally observed to follow the Gutenberg-Richter (G-R) distribution. On some major faults, however, paleoseismic rates are higher than a G-R extrapolation from the modern rate of small earthquakes would predict. This, along with other observations, led to formulation of the characteristic earthquake hypothesis, which hold
Authors
Morgan T. Page, Karen Felzer
Trench logs, terrestrial lidar system imagery, and radiocarbon data from the kilometer-62 site on the Greenville Fault, southeastern Alameda County, California, 2014
In 2014, we investigated an abrupt 8.5-meter (m), right-laterally deflected stream channel located near the Greenville Fault in southeastern Alameda County, California (-121.56224° E, 37.53430° N) that we discovered using 0.5-m resolution, 2011 aerial lidar imagery flown along the active fault trace. Prior to trenching we surveyed the site using a terrestrial lidar system (TLS) to document the exa
Authors
James J. Lienkaemper, Stephen B. DeLong, Nikita N. Avdievitch, Alexandra J. Pickering, Thomas P. Guilderson
NGA-West 2 GMPE average site coefficients for use in earthquake-resistant design
Site coefficients corresponding to those in tables 11.4–1 and 11.4–2 of Minimum Design Loads for Buildings and Other Structures published by the American Society of Civil Engineers (Standard ASCE/SEI 7-10) are derived from four of the Next Generation Attenuation West2 (NGA-W2) Ground-Motion Prediction Equations (GMPEs). The resulting coefficients are compared with those derived by other researcher
Authors
Roger D. Borcherdt
Chance findings about early holocene tidal marshes of Grays Harbor, Washington, in relation to rapidly rising seas and great subduction earthquakes
Tidal marshes commonly build upward apace with gradual rise in the level of the sea. It is expected, however, that few tidal marshes will keep up with accelerated sea-level rise later in this century. Tidal marshes have been drowned, moreover, after subsiding during earthquakes.
This report tells of ancient marshes that endured rapid sea-level rise in a region that subsides during earthquakes. The
Authors
James B. Phipps, Eileen Hemphill-Haley, Brian F. Atwater