Publications
Filter Total Items: 2574
Evolution of fracture permeability of ultramafic rocks undergoing serpentinization at hydrothermal conditions: An experimental study
We performed flow-through laboratory experiments on five cylindrically cored samples of ultramafic rocks, in which we generated a well-mated through-going tensile fracture, to investigate evolution of fracture permeability during serpentinization. The samples were tested in a triaxial loading machine at a confining pressure of 50 MPa, pore pressure of 20 MPa, and temperature of 260°C, simulating a
Authors
Aida Farough, Diane E. Moore, David A. Lockner, R.P. Lowell
Identifying long term empirical relationships between storm characteristics and episodic groundwater recharge
Shallow aquifers are an important source of water resources and provide base flow to streams; yet actual rates of groundwater recharge are difficult to estimate. While climate change is predicted to increase the frequency and magnitude of extreme precipitation events, the resulting impact on groundwater recharge remains poorly understood. We quantify empirical relations between precipitation chara
Authors
Arik Tashie, Benjamin B. Mirus, Tamlin Pavelsky
Seismic velocity structure of the crust and shallow mantle of the Central and Eastern United States by seismic surface wave imaging
Seismic surface waves from the Transportable Array of EarthScope's USArray are used to estimate phase velocity structure of 18 to 125 s Rayleigh waves, then inverted to obtain three-dimensional crust and upper mantle structure of the Central and Eastern United States (CEUS) down to ∼200 km. The obtained lithosphere structure confirms previously imaged CEUS features, e.g., the low seismic-velocity
Authors
Fred Pollitz, Walter D. Mooney
Along-strike variations in fault frictional properties along the San Andreas Fault near Cholame, California from joint earthquake and low-frequency earthquake relocations
Recent observations of low‐frequency earthquakes (LFEs) and tectonic tremor along the Parkfield–Cholame segment of the San Andreas fault suggest slow‐slip earthquakes occur in a transition zone between the shallow fault, which accommodates slip by a combination of aseismic creep and earthquakes (<15 km depth), and the deep fault, which accommodates slip by stable sliding (>35 km depth). However,
Authors
Rebecca M. Harrington, Elizabeth S. Cochran, Emily M. Griffiths, Xiangfang Zeng, Clifford H. Thurber
Animated tectonic reconstruction of the Lower Colorado River region: Implications for Late Miocene to Present deformation
Although the majority of late Miocene to present Pacific-North America plate boundary strain has been accommodated by faults of the San Andreas and Gulf of California systems, growing evidence of dextral shear east of the San Andreas Fault indicates that a component of plate boundary deformation occurred in the lower Colorado River (LoCR) region. Large-scale tectonic reconstructions across the Gul
Authors
Scott E. K. Bennett, Michael H. Darin, Rebecca J. Dorsey, Lisa A. Skinner, Paul J. Umhoefer, Michael E. Oskin
Significance of beating observed in earthquake responses of buildings
The beating phenomenon observed in the recorded responses of a tall building in Japan and another in the U.S. are examined in this paper. Beating is a periodic vibrational behavior caused by distinctive coupling between translational and torsional modes that typically have close frequencies. Beating is prominent in the prolonged resonant responses of lightly damped structures. Resonances caused by
Authors
Mehmet Çelebi, S. F. Ghahari, E. Taciroglu
Site effects in Port-au-Prince (Haiti) from the analysis of spectral ratio and numerical simulations.
To provide better insight into seismic ground motion in the Port‐au‐Prince metropolitan area, we investigate site effects at 12 seismological stations by analyzing 78 earthquakes with magnitude smaller than 5 that occurred between 2010 and 2013. Horizontal‐to‐vertical spectral ratio on earthquake recordings and a standard spectral ratio were applied to the seismic data. We also propose a simplifie
Authors
Sadrac St. Fleur, Etienne Bertrand, Francoise Courboulex, Bernard Mercier de Lépinay, Anne Deschamps, Susan E. Hough, Giovanna Cultrera, Dominique Boisson, Claude Prepetit
Potentially induced earthquakes during the early twentieth century in the Los Angeles Basin
Recent studies have presented evidence that early to mid‐twentieth‐century earthquakes in Oklahoma and Texas were likely induced by fossil fuel production and/or injection of wastewater (Hough and Page, 2015; Frohlich et al., 2016). Considering seismicity from 1935 onward, Hauksson et al. (2015) concluded that there is no evidence for significant induced activity in the greater Los Angeles region
Authors
Susan E. Hough, Morgan T. Page
Rotational seismology
Rotational seismology is an emerging study of all aspects of rotational motions induced by earthquakes, explosions, and ambient vibrations. It is of interest to several disciplines, including seismology, earthquake engineering, geodesy, and earth-based detection of Einstein’s gravitation waves.Rotational effects of seismic waves, together with rotations caused by soil–structure interaction, have b
Authors
William H. K. Lee
Complexity Theory
A complex system consists of many interacting parts, generates new collective behavior through self organization, and adaptively evolves through time. Many theories have been developed to study complex systems, including chaos, fractals, cellular automata, self organization, stochastic processes, turbulence, and genetic algorithms.
Authors
William H. K. Lee
Tectonic tremor
Tectonic, non-volcanic tremor is a weak vibration of ground, which cannot be felt by humans but can be detected by sensitive seismometers. It is defined empirically as a low-amplitude, extended duration seismic signal associated with the deep portion (∼20–40 km depth) of some major faults. It is typically observed most clearly in the frequency range of 2–8 Hz and is depleted in energy at higher fr
Authors
David R. Shelly
A comparison of observed and predicted ground motions from the 2015 MW7.8 Gorkha, Nepal, earthquake
We use 21 strong motion recordings from Nepal and India for the 25 April 2015 moment magnitude (MW) 7.8 Gorkha, Nepal, earthquake together with the extensive macroseismic intensity data set presented by Martin et al. (Seism Res Lett 87:957–962, 2015) to analyse the distribution of ground motions at near-field and regional distances. We show that the data are consistent with the instrumental peak g
Authors
Susan E. Hough, Stacey S. Martin, V. Gahalaut, A. Joshi, M. Landes, R. Bossu