Publications

This appendix to the WGCEP Earthquake Rate Model 2 summarizes geologic data and documents the development of the rupture models for the Elsinore, San Jacinto, and Garlock faults. For the summary of available geologic data, the documentation is organized by fault and fault segment and includes a summary of slip rates, event timing and recurrence, slip-per-event, and historical seismicity...

This appendix discusses how we compute the magnitude and rate of earthquake ruptures for the seven Type-A faults (Elsinore, Garlock, San Jacinto, S. San Andreas, N. San Andreas, Hayward-Rodgers Creek, and Calaveras) in the WGCEP/NSHMP Earthquake Rate Model 2 (referred to as ERM 2. hereafter). By definition, Type-A faults are those that have relatively abundant paleoseismic information (e...

This report describes development of fault parameters for the 2007 update of the National Seismic Hazard Maps and the Working Group on California Earthquake Probabilities (WGCEP, 2007). These reference parameters are contained within a database intended to be a source of values for use by scientists interested in producing either seismic hazard or deformation models to better understand...

Empirically the rate of earthquakes = magnitude M is well fit by the Gutenberg-Richter relationship, logN=a-bM (1) where N is the number of earthquakes = M over a given time period, a is the number of M = 0 earthquakes over the same period, and b is a parameter that determines the ratio of larger to smaller earthquakes (Ishimoto and Iida 1939; Gutenberg and Richter 1944). Thus to...

This appendix provides an earthquake catalog for California and the surrounding area. Our goal is to provide a listing for all known M > 5.5 earthquakes that occurred from 1850-1932 and all known M > 4.0 earthquakes that occurred from 1932-2006 within the region of 31.0 to 43.0 degrees North and -126.0 to -114.0 degrees West. Some pre-1932 earthquakes 4 M 5.5 are also listed. The...

To construct the Modified Mercalli Intensity (MMI) ShakeMap for the 1868 Hayward earthquake, we started with two sets of damage descriptions and felt reports. The first set of 100 sites was compiled by A.A. Bullock in the Lawson (1908) report on the 1906 San Francisco earthquake. The second set of 45 sites was compiled by Toppozada et al. (1981) from an extensive search of newspaper...

California?s 35 million people live among some of the most active earthquake faults in the United States. Public safety demands credible assessments of the earthquake hazard to maintain appropriate building codes for safe construction and earthquake insurance for loss protection. Seismic hazard analysis begins with an earthquake rupture forecast?a model of probabilities that earthquakes...

On October 21, 1868, a magnitude 6.8 earthquake struck the San Francisco Bay region. Although the region was then sparsely populated, this quake on the Hayward Fault was one of the most destructive in California's history. Recent studies show that such powerful Hayward Fault quakes have repeatedly jolted the region in the past. U.S. Geological Survey (USGS) scientists describe this fault...

In a new comprehensive study, scientists have determined that the chance of having one or more magnitude 6.7 or larger earthquakes in the California area over the next 30 years is greater than 99%. Such quakes can be deadly, as shown by the 1989 magnitude 6.9 Loma Prieta and the 1994 magnitude 6.7 Northridge earthquakes. The likelihood of at least one even more powerful quake of...

The great 1906 San Francisco earthquake is perhaps the landmark event in the history of earthquake science. It began with a foreshock at 5:12 a.m. local time in the morning of 18 April 1906. Some 30 sec later, the main event initiated on the San Andreas fault, just off the San Francisco coast (Lawson, 1908). Within 90 sec, nearly 480 km of the San Andreas fault ruptured (see Fig. 1)...

A long sequence of earthquakes, eight with magnitudes between 5 and 6, struck the Umbria and Marche regions of central Italy between September 26, 1997 and July 1998. The earthquake swarm caused severe structural damage, particularly to masonry buildings, and resulted in the loss of twelve lives and about 150 injuries. The source of the events was a single seismogenic structure that...

The Philippine Sea and Pacific plate slabs both subduct beneath Tokyo, and so their configuration and seismic potential have been subject to intensive study. Previous work suggests that the Philippine Sea slab extends up to 100 km northwest of Tokyo and subducts to a depth of 90 km beneath the Kanto basin, where it is folded against the underlying Pacific slab. Here we evaluate seismic...