Publications

To better understand the structure of the San Andreas fault (SAF) at Burro Flats in southern California, we acquired a three-dimensional combined set of seismic reflection and refraction profiles centered on the main active trace at Burro Flats. In this article, we discuss the variation in shallow-depth velocities along each seismic profile, with special emphasis on the 1500 m/sec P-wave velocity

A key question in earthquake hazard analysis is whether individual faults within fault zones represent independent seismic sources. For the Seattle fault zone, an upper plate structure within the Cascadia convergent margin, evaluating seismic hazard requires understanding how north-side-up, bedding-plane reverse faults, which generate late Holocene fault scarps, interact with the north-vergent mas

The U.S. / Japan Natural Resources (UJNR) Panel on Earthquake Research promotes advanced study toward a more fundamental understanding of the earthquake process and hazard estimation. The Panel promotes basic and applied research to improve our understanding of the causes and effects of earthquakes and to facilitate the transmission of research results to those who implement hazard reduction measu

The U.S. Geological Survey has recently released a 2008 version of the probabilistic National Seismic Hazard Maps. These maps plot the peak ground acceleration (PGA) and spectral acceleration (SA) ordinates at 0.2 and 1.0 sec with 2% and 10% probabilities of being exceeded in 50 years, corresponding to earthquake return periods of about 2,475 and 475 years, respectively. These acceleration levels

The inventory of structures in heavily urbanized communities within the greater San Francisco (SF) Bay area that will experience strong ground motions from the rupture of the Hayward Fault includes a variety of types of recent and older structures built with a variety of materials and to different code standards. Those who remember the effects of the 1989 Loma Prieta earthquake on structures in th

This Report introduces and summarizes the new Virtual Data Center (VDC) Tagged Format (VTF) Tool, which was developed by a diverse group of seismologists, earthquake engineers, and information technology professionals for internal use by the COSMOS VDC and other interested parties for the exchange, archiving, and analysis of earthquake strong-ground-motion data.

Maps showing the probability of surface manifestations of liquefaction in the northern Santa Clara Valley were prepared with liquefaction probability curves. The area includes the communities of San Jose, Campbell, Cupertino, Los Altos, Los Gatos Milpitas, Mountain View, Palo Alto, Santa Clara, Saratoga, and Sunnyvale. The probability curves were based on complementary cumulative frequency distrib

No abstract available.

This report lists a number of FORTRAN programs that I have developed over the years for processing and manipulating strong-motion accelerograms. The collection is titled TSPP, which stands for Time Series Processing Programs. I have excluded 'strong-motion accelerograms' from the title, however, as the boundary between 'strong' and 'weak' motion has become blurred with the advent of broadband sens

Locations (intensity centers) and moment magnitude M for 24 earthquakes (1858-1911) in the southern San Francisco Bay area are estimated from Modified Mercalli intensity (MMI) assignments. The uncertainties in location and M are generally large because there are few MMI assignments available. Preferred locations are selected to be consistent with a simple model for seismic activity on the central

In this report, we present seismic data and acquisition parameters for two seismic profiles acquired in the San Bernardino, California area in May and October 2003. We refer to these seismic profiles as the San Bernardino Regional (SBR) and San Bernardino High-Resolution (SBHR) seismic profiles. We present both un-interpreted and interpreted seismic images so that the structure of the area can ind

The question is not if but when southern California will be hit by a major earthquake - one so damaging that it will permanently change lives and livelihoods in the region. How severe the changes will be depends on the actions that individuals, schools, businesses, organizations, communities, and governments take to get ready. To help prepare for this event, scientists of the U.S. Geological Surve