Acceptance Criteria for Offshore Platforms”,

A platform complex in the Nort

Future Seismic Hazards in Southern California - Phase I: Implications of the 1992 Landers Earthquake Sequence

Southern California and its seismologists received a wake-up call on June 28, 1992. The largest earthquake to strike southern California in 40 years occurred near the town of Landers, located 30 km north of the San Andreas fault. It had a magnitude of 7.5 (M7.5). Three and one-half hours later, a M6.5 aftershock struck the Big Bear area 40 km (kilometers) to the west of Landers. An ad hoc working group was rapidly convened in July, 1992, to evaluate how the Landers-Big Bear earthquake sequence might affect future large earthquakes along major faults in southern California. In particular, what are the chances of large earthquakes in the next few years and how do they compare to previous estimates (such as those of the Working Group on California Earthquake Probabilities -- WGCEP, 1988)? Such an evaluation was made for central California after the Lorna Prieta earthquake of 1989 (WGCEP, 1990). The charge to the Landers ad hoc working group included analyzing the seismicity for the last several years in southern California and the new paleoseismic, geologic, and geodetic data recently available for southern California. To inform the public about the potential hazard of plausible earthquakes, the working group was also asked to map the predicted severity of ground shaking for such earthquakes compared to that from the Landers earthquake

Probabilities of Large Earthquakes in the San Francisco Bay Region, California

In 1987 a Working Group on California Earthquake Probabilities was organized by the U.S. Geological Survey at the recommendation of the National Earthquake Prediction Evaluation Council (NEPEC). The membership included representatives from private industry, academia, and the U.S. Geological Survey. The Working Group computed long-term probabilities of earthquakes along the major faults of the San Andreas fault system on the basis of consensus interpretations of information then available. Faults considered by the Working Group included the San Andreas fault proper, the San Jacinto and Imperial-faults of southern California, and the Hayward fault of northern California. The Working Group issued a final report of its findings in 1988 (Working Group, 1988) that was reviewed and endorsed by NEPEC. As a consequence of the magnitude 7.1 Loma Prieta, California, earthquake of October 17, 1989, a second Working Group on California Earthquake Probabilities was organized under the auspices of NEPEC. Its charge was to review and, as necessary, revise the findings of the 1988 report on the probability of large earthquakes in the San Francisco Bay region. In particular, the Working Group was requested to examine the probabilities of large earthquakes in the context of new interpretations or physical changes resulting from the Loma Prieta earthquake. In addition, it was to consider new information pertaining to the San Andreas and other faults in the region obtained subsequent to the release of the 1988 report. Insofar as modified techniques and improved data have been used in this study, the same approach might also, of course, modify the probabilities for southern California. This reevaluation has, however, been specifically limited to the San Francisco Bay region. This report is intended to summarize the collective knowledge and judgments of a diverse group of earthquake scientists to assist in formulation of rational earthquake policies. A considerable body of information about active faults in the San Francisco Bay region leads to the conclusion that major earthquakes are likely within the next tens of years. Several techniques can be used to compute probabilities of future earthquakes, although there are uncertainties about the validity of specific assumptions or models that must be made when applying these techniques. The body of this report describes the data and detailed assumptions that lead to specific probabilities for different fault segments. Additional data and future advances in our understanding of earthquake physics may alter the way that these probabilities are estimated. Even though this uncertainty must be acknowledged, we emphasize that the findings of this report are supported by other lines of argument and are consistent with our best understanding of the likelihood for the occurrence of earthquakes in the San Francisco Bay region

Probability, statistics, and decision for civil engineers

xiv+684hlm.;24c

Application of incremental dynamic analysis to an RC-structure

concrete, multistor