Publications

This isostatic residual gravity map is part of a regional effort to investigate the tectonics and water resources of the central Coast Range. This map serves as a basis for modeling the shape of basins and for determining the location and geometry of faults in the area. Local spatial variations in the Earth's gravity field (after removing variations caused by instrument drift, earth...

Sandy deposits from the 29 September 2009 tsunami on the east coast of Upolu, Samoa were investigated to document their characteristics and used to apply an inverse sediment transport model to estimate tsunami flow speed. Sandy deposits 6 to 15 cm thick formed from ~ 25 to ~ 250 m inland. Sedimentary layers in the deposits, that are defined by vertical grain size variation and contacts...

The Volcano Hazards Program of the U.S. Geological Survey (USGS) is part of the Geologic Hazards Assessments subactivity as funded by congressional appropriation. Investigations are carried out in the USGS and with cooperators at the Alaska Division of Geological and Geophysical Surveys, University of Alaska Fairbanks Geophysical Institute, University of Hawaii Manoa and Hilo, University...

High seismicity levels with accelerating uplift (under the resurgent dome) in Long Valley caldera in the eastern Sierra Nevada from 1989 to 1997, triggered upgrades to dilational strainmeters and other instrumentation installed in the early 1980's following a series of magnitude 6 earthquakes. This included two additional high-resolution borehole strainmeters and replacement of the...

In July 2010, in an effort to reduce future catastrophic natural disaster losses for California, the American Red Cross coordinated and sent a delegation of 20 multidisciplinary experts on earthquake response and recovery to Chile. The primary goal was to understand how the Chilean society and relevant organizations responded to the magnitude 8.8 Maule earthquake that struck the region...

We present a detailed description and users manual for a new tool to evaluate seismic station performance and characteristics by providing quick and easy transitions between visualizations of the frequency and time domains. The software is based on the probability density functions (PDF) of power spectral densities (PSD) (McNamara and Buland, 2004) and builds on the original development...

No abstract available.

Using cryogenic scanning electron microscopy (CSEM), powder X-ray diffraction, and gas chromatography methods, we investigated the physical states, grain characteristics, gas composition, and methane isotopic composition of two gas-hydrate-bearing sections of core recovered from the BPXA–DOE–USGS Mount Elbert Gas Hydrate Stratigraphic Test Well situated on the Alaska North Slope. The...

The generation of seismicity catalogs on synthetic fault networks holds the promise of providing key inputs into probabilistic seismic-hazard analysis, for example, the coefficient of variation, mean recurrence time as a function of magnitude, the probability of fault-to-fault ruptures, and conditional probabilities for foreshock–mainshock triggering. I employ a seismicity simulator that...

No abstract available.

The operational version of the United States Geological Survey one-minute Dst index (a global geomagnetic disturbance-intensity index for scientific studies and definition of space-weather effects) uses either four- or three-station input (including Honolulu, Hawaii; San Juan, Puerto Rico; Hermanus, South Africa; and Kakioka, Japan; or Honolulu, San Juan and Guam) and a method based on...

Interactions between hydrothermal fluids and rock alter mineralogy, leading to the formation of secondary minerals and potentially significant physical and chemical property changes. Reactive transport simulations are essential for evaluating the coupled processes controlling the geochemical, thermal and hydrological evolution of geothermal systems. The objective of this preliminary...