Publications

The general correlation of Salt Lake Valley sites located on soft, saturated unconsolidated silty and clayey deposits (that is, deposits with low S-wave velocity) with high seismic amplification at the ground surface motivated our investigation of the relationship between the P- and S-wave seismic velocity (Vp and Vs) of these units and their corresponding observed site response. We found that low

More than 3,000 landslides were triggered by heavy rainfall in the central Appalachian Mountains of West Virginia and Virginia, November 3-5, 1985. These landslides provided the opportunity to study spatial controls on landslides, magnitude and frequency of triggering events, and the effects of landslides on flood-induced geomorphic change. The study area consists of parts of the Wills Mountain an

The Parkfield earthquake prediction is generally stated as a 95% probability that the next moderate earthquake there should occur before January 1993. That time limit is based on a two-sided 95% confidence interval. Because at the time of the prediction (1985) it was already clear that the earthquake had not occurred prior to 1985, a one-sided 95% confidence interval would have been more appropria

Landslides are triggered by factors such as heavy rainfall, seismic activity, and construction on hillslopes. The leading cause of landslides in Puerto Rico is intense and/or prolonged rainfall. A rainfall threshold for rainfall-triggered landsliding is delimited by 256 storms that occurred between 1959 and 1991 in the central mountains of Puerto Rico, where mean annual rainfall is close to or in

Paleointensity determinations have been obtained from 22 basaltic lava flows on the island of Hawaii using the Thelliers' method. Radiocarbon dating indicates that these flows erupted at intervals ranging from about 200 to 1000 years, and results of the experiments provide an estimate of broad trends in geomagnetic paleointensity during Holocene time in the vicinity of Hawaii. Most of the samples

Severe earthquakes of the last decade in Mexico, Armenia, and the United States have reemphasized the importance of local geologic site conditions in estimating damage and consequent losses. Recent advances in geographic information system (GIS) technology have created new opportunities for maintaining and integrating extensive spatial databases for applications in seismic hazard analysis. Ground

The Thwaites Glacier/iceberg tongue complex has been a significant feature of the Antarctic coastline for at least 50 years. In 1986, major changes began to occur in this area. Fast ice melted and several icebergs calved from the base of the iceberg tongue and the terminus of Thwaites Glacier. The iceberg tongue rotated to an east-west orientation and drifted westward. Between 1986 and 1992, a tot

Nestled in the crater of Oregon's majestic Mount Hood volcano is Crater Rock, a prominent feature known to thousands of skiers, climbers, and tourists who journey each year to the famous Timberline Lodge located high on the volcano's south flank. Crater Rock stands about 100m above the sloping crater floor and warm fumaroles along its base emit sulfur gases and a faint steam plume that is sometime

By analyzing two landslides in the New Madrid seismic zone, we develop an approach for judging if a landslide or group of landslides of unknown origin was more likely to have formed as a result of earthquake shaking or in aseismic conditions. The two landslides analyzed are representative of two groups of land-slides that previous research on the geomorphology and regional distribution of landslid

Conceptual models of the thermal structure of the Oregon Cascade Range propose either (1) a narrow zone of magmatic heat sources, flanked by shallow heat-flow anomalies caused by lateral ground-water flow; or (2) a wide zone of magmatic heat sources, with localized, generally negligible ground-water effects. The proposed narrow heat source coincides with the Quaternary volcanic arc, whereas the wi

A method for mapping hazard posed by debris flows has been developed and applied to an area near Honolulu, Hawaii. The method uses studies of past debris flows to characterize sites of initiation, volume at initiation, and volume-change behavior during flow. Digital simulations of debris flows based on these characteristics are then routed through a digital elevation model (DEM) to estimate degree

The US Geological Survey (USGS) Landslide Hazards Reduction Program includes studies of landslide process and prediction, landslide susceptibility and risk mapping, landslide recurrence and slope evolution, and research application and technology transfer. Studies of landslide processes have been recently conducted in Virginia, Utah, California, Alaska, and Hawaii, Landslide susceptibility maps pr