Publications

This report is the second of two reports on seismic imaging investigations conducted by the U.S. Geological Survey (USGS) during the summers of 1997 and 1998 in the Cherry Valley area in California (Figure 1a). In the first report (Catchings et al., 1999), data and interpretations were presented for four seismic imaging profiles (CV-1, CV-2, CV-3, and CV-4) acquired during the summer of...

Following the 1994 Mw=6.7 Northridge earthquake, a 65‐km‐long, north‐south array of 11 geodetic monuments was established across the rupture. The array was surveyed with GPS ten times in the 4.25 yr after the earthquake. Although there is evidence for modest nonlinear postseismic relaxation in the first few weeks after the Northridge earthquake, the deformation in the subsequent four...

A linear array of 15 geodetic monuments was installed in 1993 across the rupture zone of the 1964 Alaska earthquake (Mw = 9.2). The array extends from Middleton Island (at the edge of the continental shelf and 80 km from the Alaska‐Aleutian trench) to north of Palmer, Alaska (380 km from the trench), in the approximate direction of Pacific‐North American plate convergence (N15.5°W). The...

We discuss three interconnected processes that occur during continental compression and extension: delamination of the lower crust and sub-crustal lithosphere, escape tectonics (i.e., lateral crustal flow), and crustal uplift. We combine calculations of lithospheric viscosity–depth curves with geologic observations and seismic images of the deep crust to infer the mechanisms controlling...

Satellite interferometric synthetic aperture radar is uniquely suited to monitoring year-to-year deformation of the entire Yellowstone caldera (about 3000 square kilometers). Sequential interferograms indicate that subsidence within the caldera migrated from one resurgent dome to the other between August 1992 and August 1995. Between August 1995 and September 1996, the caldera region...

Stress shadows generated by California's two most recent great earthquakes (1857 Fort Tejon and 1906 San Francisco) substantially modified 19th and 20th century earthquake history in the Los Angeles basin and in the San Francisco Bay area. Simple Coulomb failure calculations, which assume that earthquakes can be modeled as static dislocations in an elastic half-space, have done quite...

Three-dimensional velocity models for Puget Sound provide a means for better understanding the lateral variations in strong ground motions recorded during local earthquakes in Puget Lowland. We have compiled 29 sonic and density logs from 23 oil test wells to help us determine the geometry and physical properties of the Cenozoic basins in western Washington. The maximum depths sampled by...

Geodetic arrays observed by the U.S. Coast and Geodetic Survey span the Imperial fault in southern California. For the 1940 M 7.1 Imperial Valley earthquake, a 1934–1941 triangulation network has sufficient resolution to allow inversion for the coseismic slip distribution on fault segments 5 to 25 km long extending from the surface to a depth of 9 km. The estimated right-lateral slip is...

No abstract available.

The magnitude (Mw) 6.9 Loma Prieta earthquake struck the San Francisco Bay region of central California at 5:04 p.m. P.d.t. on October 17, 1989, killing 62 people and generating billions of dollars in property damage. Scientists were not surprised by the occurrence of a destructive earthquake in this region and had, in fact, been attempting to forecast the location of the next large...

Several approaches are used to assess the performance of the built environment following an earthquake -- preliminary damage surveys conducted by professionals, detailed studies of individual structures, and statistical analyses of groups of structures. Reports of damage that are issued by many organizations immediately following an earthquake play a key role in directing subsequent...

Central California, in the vicinity of San Francisco and Monterey Bays, has a history of fatal and damaging landslides, triggered by heavy rainfall, coastal and stream erosion, construction activity, and earthquakes. The great 1906 San Francisco earthquake (MS=8.2-8.3) generated more than 10,000 landslides throughout an area of 32,000 km2; these landslides killed at least 11 people and...