Publications

Arc volcanism in Alaska is strongly correlated with the 100 km depth contour of the western Aluetian Wadati-Benioff zone. Above the eastern portion of the Wadati-Benioff zone however, there is a distinct lack of volcanism (the Denali volcanic gap). We observe high Poisson's ratio values (0.29-0.33) over the entire length of the Alaskan subduction zone mantle wedge based on regional variations of P

We compare two methods of seismic-intensity estimation from ground-motion records for the two recent strong earthquakes: the 1999 (M 7.1) Hector Mine, California, and the 1999 (M 7.6) Chi-Chi, Taiwan. The first technique utilizes the peak ground acceleration (PGA) and velocity (PGV), and it is used for rapid generation of the instrumental intensity map in California. The other method is based on t

On April 27, 1993, a large landslide in the Tully Valley, Onondaga County, NY, destroyed three houses and resulted in the evacuation of four others; it also triggered a loss of potable drinking water for about 15 homes north of the slide area and affected a total of 20 ha of land. In the 7 years following this slide, several studies have been conducted by federal and state environmental agencies a

Landslide inventory maps are generally prepared by interpreting the geomorphic expression of landsliding on aerial photos, topographic maps, or on the ground. Distinctive landslide geomorphology allows the recognition and mapping of landslides, although there are always landslides that have very subtle expression and are not identified. The difficulties of mapping landslides based on their geomorp

40Ar/39Ar ages were determined on the three major ash-flow tuffs of the Yellowstone Plateau volcanic field in the region of Yellowstone National Park in order to improve the precision of previously determined ages. Total-fusion and incremental- heating ages of sanidine yielded the following mean ages: Huckleberry Ridge Tuff—2.059 ± 0.004 Ma; Mesa Falls Tuff— 1.285 ± 0.004 Ma; and Lava Creek Tuff—

High-resolution seismic reflection profiles image discrete folds in the shallow subsurface (<600 m) above two segments of the Puente Hills blind-thrust fault system, Los Angeles basin, California. The profiles demonstrate late Quaternary activity at the fault tip, precisely locate the axial surfaces of folds within the upper 100 m, and constrain the geometry and kinematics of recent folding. The S

No abstract available.

In spite of improvements in recognition, prediction, mitigative measures, and warning systems, economic losses and casualties due to landslides in the Western Hemisphere appear to be growing as a result of increasing development of landslide-prone areas due to population pressures. This paper notes outstanding examples of socioeconomic losses in the Americas. Landslides impact the following ele

The January 13, 2001 earthquake (M-7.6) off the coast of El Salvador triggered widespread damaging landslides in many parts of the El Salvador. In the aftermath of the earthquake, the Salvadoran government requested technical assistance through the U.S. Agency for International Development (USAID); USAID, in turn, requested help from technical experts in landslide hazards from the U.S. Geological

No abstract available.

On February 13, 2001, a magnitude 6.5 earthquake occurred about 40 km eastsoutheast of the capital city of San Salvador in central El Salvador and triggered thousands of landslides in the area east of Lago de Ilopango. The landslides are concentrated in a 2,500-km2 area and are particularly abundant in areas underlain by thick deposits of poorly consolidated, late Pleistocene and Holoce

Since the early 1990's, the magnitude and location of an earthquake have been available within minutes on the Internet. Now, as a result of work by the U.S. Geological Survey (USGS) and with the cooperation of various regional seismic networks, people who experience an earthquake can go online and share information about its effects to help create a map of shaking intensities and damage. Such 'Com