Publications

The southern Whidbey Island fault zone (SWIF), as previously mapped using borehole data, potential field anomalies, and marine seismic reflection surveys, consists of three subparallel, northwest trending strands extending ∼100 km from near Vancouver Island to the northern Puget Lowland. East of Puget Sound, the SWIF makes landfall between the cities of Seattle and Everett but is...

This Appendix contains 3 sections that 1) documents published observations of surface creep on California faults, 2) constructs line integrals across the WG-07 deformation model to compare to the Pacific - North America plate motion, and 3) constructs strain tensors of volumes across the WG-07 deformation model to compare to the Pacific - North America plate motion. Observation of creep...

This appendix presents elastic-rebound-theory (ERT) motivated time-dependent probabilities, conditioned on the date of last earthquake, for the segmented type-A fault models of the 2007 Working Group on California Earthquake Probabilities (WGCEP). These probabilities are included as one option in the WGCEP?s Uniform California Earthquake Rupture Forecast 2 (UCERF 2), with the other...

This appendix describes how a-priori rupture models were developed for the northern California Type-A faults. As described in the main body of this report, and in Appendix G, “a-priori” models represent an initial estimate of the rate of single and multi-segment surface ruptures on each fault. Whether or not a given model is moment balanced (i.e., satisfies section slip-rate data)...

The geometry and recurrence times of large earthquakes associated with the Cascadia Subduction Zone (CSZ) were discussed and debated at a March 28-29, 2006 Pacific Northwest workshop for the USGS National Seismic Hazard Maps. The CSZ is modeled from Cape Mendocino in California to Vancouver Island in British Columbia. We include the same geometry and weighting scheme as was used in the...

No abstract available.

The Walnut paleoseismic site is located along the northern San Jacinto fault about 3 km southeast of the San Bernardino, California city center (Figures 1, 2). More than 340 meters of trenches were excavated across the fault zone at this site as part of an Alquist-Priolo fault study (Figure 3). We photographed and logged the SE wall and most of the NE wall of trench 1, both walls of...

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...

Paleoearthquake observations often lack enough events at a given site to directly define a probability density function (PDF) for earthquake recurrence. Sites with fewer than 10-15 intervals do not provide enough information to reliably determine the shape of the PDF using standard maximum-likelihood techniques [e.g., Ellsworth et al., 1999]. In this paper I present a method that...

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...

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...

The background seismicity model is included to account for M 5.0 - 6.5 earthquakes on faults and for random M 5.0 ? 7.0 earthquakes that do not occur on faults included in the model (as in earlier models of Frankel et al., 1996, 2002 and Petersen et al., 1996). We include four different classes of earthquake sources in the California background seismicity model: (1) gridded (smoothed)...