Publications

The Bluegill landslide, located in south-central Idaho, is part of a larger landslide complex that forms an area the Salmon Falls Creek drainage named Sinking Canyon Recent movement of the Bluegill landslide, apparently beginning sometime in late 1998 or early 1999, has caused a 4.5 ha area of the canyon rim to drop as much as 8 m and move horizontally several meters into the canyon. Upward moveme

Results of a present preliminary assessment of the probability of debris-flow activity and estimates of peak discharges that can potentially be generated by debris flows issuing from basins burned by the Padua Fire of October 2003 in southern California in response to 25-year, 10-year, and 2-year recurrence, 1-hour duration rain storms are presented. The resulting probability maps are based on the

Gravity, magnetic, and seismicity data profiled across the Hayward Fault Zone were generated as part of ongoing studies to help determine the geologic and tectonic setting of the San Francisco Bay region. These data, combined with previous geophysical studies that indicate that the Hayward Fault Zone dips 75°NE near San Leandro and follows a preexisting structure, reveal a possible direct connecti

The Humboldt River Basin is an arid to semiarid, internally drained basin that covers approximately 43,000 km2 in northern Nevada. The basin contains a wide variety of metallic and nonmetallic mineral deposits and occurrences, and, at various times, the area has been one of the Nation's leading or important producers of gold, silver, copper, mercury, and tungsten. Nevada currently (2003) is the th

We study how the fault dip and slip rake angles affect near-source ground velocities and displacements as faulting transitions from strike-slip motion on a vertical fault to thrust motion on a shallow-dipping fault. Ground motions are computed for five fault geometries with different combinations of fault dip and rake angles and common values for the fault area and the average slip. The nature of

The 2002 M7.9 Denali fault, Alaska, earthquake triggered thousands of landslides, primarily rock falls and rock slides, that ranged in volume from rock falls of a few cubic meters to rock avalanches having volumes as great as 15 ?? 106 m3. The pattern of landsliding was unusual; the number of slides was less than expected for an earthquake of this magnitude, and the landslides were concentrated in

The coastal infrastructure of the southern greater Los Angeles metropolitan area would be profoundly affected by a large tsunami. Submarine slope failures and active faults, either of which could have generated a tsunami, are known on the shelf and slope near Long Beach. Large slope failures are present on the San Pedro Escarpment and on the basin slope adjacent to the San Pedro shelf. The southea

The integration of remote-sensing and in-situ observations, and assimilation of these observations into high-resolution mesoscale models was described. It was observed that the greatest loss of life and property is the direct result of the storm because of the high winds and heavy rain. The research were conducted to develop a warning system that included satellite observations to track dangerous

Mathematical models of soil nonlinearity in common use and recently developed nonlinear codes compared to investigate the range of their predictions. We consider equivalent linear formulations with and without frequency-dependent moduli and damping ratios and nonlinear formulations for total and effective stress. Average velocity profiles to 150 m depth with midrange National Earthquake Hazards Re

The ground motion hazard for Sumatra and the Malaysian peninsula is calculated in a probabilistic framework, using procedures developed for the US National Seismic Hazard Maps. We constructed regional earthquake source models and used standard published and modified attenuation equations to calculate peak ground acceleration at 2% and 10% probability of exceedance in 50 years for rock site conditi

Displacement, velocity, and velocity-squared records of P and SH body waves recorded at teleseismic distances are analyzed to determine the rupture characteristics of the Denali fault, Alaska, earthquake of 3 November 2002 (MW 7.9, Me 8.1). Three episodes of rupture can be identified from broadband (∼0.1–5.0 Hz) waveforms. The Denali fault earthquake started as a  MW 7.3 thrust event. Subsequent r

These maps present preliminary assessments of the probability of debris-flow activity and estimates of peak discharges that can potentially be generated by debris flows issuing from basins burned by the Cedar and Paradise Fires of October 2003 in southern California in response to 25-year, 10-year, and 2-year recurrence, 1-hour duration rain storms. The probability maps are based on the applicatio