Publications
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Time-dependent seismic tomography
Of methods for measuring temporal changes in seismic-wave speeds in the Earth, seismic tomography is among those that offer the highest spatial resolution. 3-D tomographic methods are commonly applied in this context by inverting seismic wave arrival time data sets from different epochs independently and assuming that differences in the derived structures represent real temporal variations. This a
Authors
B. R. Julian, G. R. Foulger
Computer algorithm for analyzing and processing borehole strainmeter data
The newly installed Plate Boundary Observatory (PBO) strainmeters record signals from tectonic activity, Earth tides, and atmospheric pressure. Important information about tectonic processes may occur at amplitudes at and below tidal strains and pressure loading. If incorrect assumptions are made regarding the background noise in the strain data, then the estimates of tectonic signal amplitudes ma
Authors
John O. Langbein
Ground motion hazard from supershear rupture
An idealized rupture, propagating smoothly near a terminal rupture velocity, radiates energy that is focused into a beam. For rupture velocity less than the S-wave speed, radiated energy is concentrated in a beam of intense fault-normal velocity near the projection of the rupture trace. Although confined to a narrow range of azimuths, this beam diverges and attenuates. For rupture velocity greater
Authors
D. J. Andrews
Seismic hazard mapping of California considering site effects
In this paper, we have combined the U.S. Geological Survey's National Seismic Hazard Maps model with the California geologic map showing 17 generalized geologic units that can be defined by their VS30. We regrouped these units into seven VS30 values and calculated a probabilistic seismic hazard map for the entire state for each VS30 value. By merging seismic hazard maps based on the seven differen
Authors
E. Kalkan, C.J. Wills, D.M. Branum
Migrating tremors illuminate complex deformation beneath the seismogenic San Andreas fault
The San Andreas fault is one of the most extensively studied faults in the world, yet its physical character and deformation mode beneath the relatively shallow earthquake-generating portion remain largely unconstrained. Tectonic ‘non-volcanic’ tremor, a recently discovered seismic signal probably generated by shear slip on the deep extension of some major faults, can provide new insight into the
Authors
David R. Shelly
Imaging hydraulic fractures in a geothermal reservoir
No abstract available.
Authors
Bruce R. Julian, Gillian R. Foulger
Normal-faulting slip maxima and stress-drop variability: A geological perspective
We present an empirical estimate of maximum slip in continental normal-faulting earthquakes and present evidence that stress drop in intraplate extensional environments is dependent on fault maturity. A survey of reported slip in historical earthquakes globally and in latest Quaternary paleoearthquakes in the Western Cordillera of the United States indicates maximum vertical displacements as large
Authors
Suzanne Hecker, T. E. Dawson, D. P. Schwartz
Liquefaction caused by the 2009 Olancha, California (USA), M5.2 earthquake
The October 3, 2009 (01:16:00 UTC), Olancha M5.2 earthquake caused extensive liquefaction as well as permanent horizontal ground deformation within a 1.2 km2area earthquake in Owens Valley in eastern California (USA). Such liquefaction is rarely observed during earthquakes of M ≤ 5.2. We conclude that subsurface conditions, not unusual ground motion, were the primary factors contributing to the li
Authors
T.L. Holzer, A. S. Jayko, E. Hauksson, J.P.B. Fletcher, T.E. Noce, M.J. Bennett, C.M. Dietel, K.W. Hudnut
Decay of aftershock density with distance does not indicate triggering by dynamic stress
Resolving whether static or dynamic stress triggers most aftershocks and subsequent mainshocks is essential to understand earthquake interaction and to forecast seismic hazard. Felzer and Brodsky examined the distance distribution of earthquakes occurring in the first five minutes after 2 ≤ M
Authors
K. Richards-Dinger, R. S. Stein, S. Toda
Methane hydrate synthesis from ice: Influence of pressurization and ethanol on optimizing formation rates and hydrate yield
Polycrystalline methane gas hydrate (MGH) was synthesized using an ice-seeding method to investigate the influence of pressurization and ethanol on the hydrate formation rate and gas yield of the resulting samples. When the reactor is pressurized with CH4 gas without external heating, methane hydrate can be formed from ice grains with yields up to 25% under otherwise static conditions. The rapid t
Authors
Po-Chun. Chen, Wuu-Liang Huang, Laura A. Stern
Observing the Greatest Earthquakes: AGU Chapman Conference on Giant Earthquakes and Their Tsunamis: Viña del Mar and Valparaíso, Chile, 16–20 May 2010
An AGU Chapman Conference commemorated the fiftieth anniversary of the 1960 M 9.5 Chile earthquake. Participants reexamined this earthquake, the largest ever recorded instrumentally, and compared it with Chile's February 2010 M 8.8 earthquake. They also addressed the giant earthquake potential of subduction zones worldwide and strategies for reducing losses due to tsunamis. The conference drew 96
Authors
Brian F. Atwater, Sergio Barrientos, Inés Cifuentes, Marco Cisternas, Kelin Wang
Viscoelastic-cycle model of interseismic deformation in the northwestern United States
We apply a viscoelastic cycle model to a compilation of GPS velocity fields in order to address the kinematics of deformation in the northwestern United States. A viscoelastic cycle model accounts for time-dependent deformation following large crustal earthquakes and is an alternative to block models for explaining the interseismic crustal velocity field. Building on the approach taken in Pollitz
Authors
F. F. Pollitz, Patricia McCrory, Doug Wilson, Jerry Svarc, Christine Puskas, Robert B. Smith