Publications
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Note: Rotaphone, a new self-calibrated six-degree-of-freedom seismic sensor
We have developed and tested (calibration, linearity, and cross-axis errors) a new six-degree-of-freedom mechanical seismic sensor for collocated measurements of three translational and three rotational ground motion velocity components. The device consists of standard geophones arranged in parallel pairs to detect spatial gradients. The instrument operates in a high-frequency range (above the nat
Authors
Johana Brokešová, Jiří Málek, John R. Evans
Coseismic and postseismic stress rotations due to great subduction zone earthquakes
The three largest recent great subduction zone earthquakes (2011 M9.0 Tohoku, Japan; 2010 M8.8 Maule, Chile; and 2004 M9.2 Sumatra-Andaman) exhibit similar coseismic rotations of the principal stress axes. Prior to each mainshock, the maximum compressive stress axis was shallowly plunging, while immediately after the mainshock, both the maximum and minimum compressive stress axes plunge at ~45°. D
Authors
Jeanne L. Hardebeck
Spectral damping scaling factors for shallow crustal earthquakes in active tectonic regions
Ground motion prediction equations (GMPEs) for elastic response spectra, including the Next Generation Attenuation (NGA) models, are typically developed at a 5% viscous damping ratio. In reality, however, structural and non-structural systems can have damping ratios other than 5%, depending on various factors such as structural types, construction materials, level of ground motion excitations, amo
Authors
Sanaz Rezaeian, Yousef Bozorgnia, I.M. Idriss, Kenneth Campbell, Norman Abrahamson, Walter Silva
A mantle-driven surge in magma supply to Kīlauea Volcano during 2003-2007
The eruptive activity of a volcano is fundamentally controlled by the rate of magma supply. At Kīlauea Volcano, Hawai‘i, the rate of magma rising from a source within Earth’s mantle, through the Hawaiian hotspot, was thought to have been relatively steady in recent decades. Here we show that the magma supply to Kīlauea at least doubled during 2003–2007, resulting in dramatic changes in eruptive ac
Authors
Michael P. Poland, Asta Miklius, A. Jeff Sutton, Carl R. Thornber
Ancient impact and aqueous processes at Endeavour Crater, Mars
The rover Opportunity has investigated the rim of Endeavour Crater, a large ancient impact crater on Mars. Basaltic breccias produced by the impact form the rim deposits, with stratigraphy similar to that observed at similar-sized craters on Earth. Highly localized zinc enrichments in some breccia materials suggest hydrothermal alteration of rim deposits. Gypsum-rich veins cut sedimentary rocks ad
Authors
S. W. Squyres, R. E. Arvidson, J.F. Bell, F.J. Calef, B. C. Clark, B. A. Cohen, L.A. Crumpler, P. A. de Souza, W. H. Farrand, Ralf Gellert, J. Grant, Kenneth E. Herkenhoff, J.A. Hurowitz, J. R. Johnson, B.L. Jolliff, A.H. Knoll, R. Li, S. M. McLennan, D. W. Ming, D. W. Mittlefehldt, T. J. Parker, G. Paulsen, M.S. Rice, S. W. Ruff, C. Schröder, A. S. Yen, K. Zacny
Analysis of rainfall-induced slope instability using a field of local factor of safety
Slope-stability analyses are mostly conducted by identifying or assuming a potential failure surface and assessing the factor of safety (FS) of that surface. This approach of assigning a single FS to a potentially unstable slope provides little insight on where the failure initiates or the ultimate geometry and location of a landslide rupture surface. We describe a method to quantify a scalar fiel
Authors
Ning Lu, Başak Şener-Kaya, Alexandra Wayllace, Jonathan W. Godt
Gravity fluctuations induced by magma convection at Kilauea Volcano, Hawai'i
Convection in magma chambers is thought to play a key role in the activity of persistently active volcanoes, but has only been inferred indirectly from geochemical observations or simulated numerically. Continuous microgravity measurements, which track changes in subsurface mass distribution over time, provide a potential method for characterizing convection in magma reservoirs. We recorded gravit
Authors
Daniele Carbone, Michael P. Poland
Characterization of previously unidentified lunar pyroclastic deposits using Lunar Reconnaissance Orbiter Camera (LROC) data
We used a Lunar Reconnaissance Orbiter Camera (LROC) global monochrome Wide-angle Camera (WAC) mosaic to conduct a survey of the Moon to search for previously unidentified pyroclastic deposits. Promising locations were examined in detail using LROC multispectral WAC mosaics, high-resolution LROC Narrow Angle Camera (NAC) images, and Clementine multispectral (ultraviolet-visible or UVVIS) data. Out
Authors
J. Olaf Gustafson, James F. Bell, Lisa R. Gaddis, B. Ray Hawke, Thomas A. Giguere
Differential melt scaling for oblique impacts on terrestrial planets
Analytical estimates of melt volumes produced by a given projectile and contained in a given impact crater are derived as a function of impact velocity, impact angle, planetary gravity, target and projectile densities, and specific internal energy of melting. Applications to impact events and impact craters on the Earth, Moon, and Mars are demonstrated and discussed. The most probable oblique imp
Authors
Oleg Abramov, Stephanie M. Wong Wong, David A. Kring Kring
ShakeMap Atlas 2.0: an improved suite of recent historical earthquake ShakeMaps for global hazard analyses and loss model calibration
We introduce the second version of the U.S. Geological Survey ShakeMap Atlas, which is an openly-available compilation of nearly 8,000 ShakeMaps of the most significant global earthquakes between 1973 and 2011. This revision of the Atlas includes: (1) a new version of the ShakeMap software that improves data usage and uncertainty estimations; (2) an updated earthquake source catalogue that include
Authors
D. Garcia, R.T. Mah, K. L. Johnson, M.G. Hearne, K. D. Marano, K.-W. Lin, D. J. Wald
Developing Vs30 site-condition maps by combining observations with geologic and topographic constraints
Despite obvious limitations as a proxy for site amplification, the use of time-averaged shear-wave velocity over the top 30 m (VS30) remains widely practiced, most notably through its use as an explanatory variable in ground motion prediction equations (and thus hazard maps and ShakeMaps, among other applications). As such, we are developing an improved strategy for producing VS30 maps given the c
Authors
E.M. Thompson, D. J. Wald
The ICDP Snake River Geothermal Drilling Project: preliminary overview of borehole geophysics
Hotspot: The Snake River Geothermal Drilling Project was undertaken to better understand the geothermal systems in three locations across the Snake River Plain with varying geological and hydrological structure. An extensive series of standard and specialized geophysical logs were obtained in each of the wells. Hydrogen-index neutron and γ-γ density logs employing active sources were deployed thro
Authors
Douglas R. Schmitt, Lee M. Liberty, James E. Kessler, Jochem Kuck, Randolph Kofman, Ross Bishop, John W. Shervais, James P. Evans, Duane E. Champion