Chapter B. The Loma Prieta, California, Earthquake of October 17, 1989 - Forecasts

Edited by Harris, Ruth A.

Abstract:

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 earthquake in the San Francisco Bay region for decades. This paper summarizes more than 20 scientifically based forecasts made before the 1989 Loma Prieta earthquake for a large earthquake that might occur in the Loma Prieta area. The forecasts geographically closest to the actual earthquake primarily consisted of right-lateral strike-slip motion on the San Andreas Fault northwest of San Juan Bautista. Several of the forecasts did encompass the magnitude of the actual earthquake, and at least one approximately encompassed the along-strike rupture length. The 1989 Loma Prieta earthquake differed from most of the forecasted events in two ways: (1) it occurred with considerable dip-slip in addition to strike-slip motion, and (2) it was much deeper than expected.

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USGS Numbered Series

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38251

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Edited by Harris, Ruth A.

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USGS Earthquake Hazards Program

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ENGLISH

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The Loma Prieta, California, Earthquake of October 17, 1989: Earthquake Occurrence

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p. B1-B28

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Prepared in cooperation with the National Science Foundation

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Geological Survey (U.S.)

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Professional Paper

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1550-B

Citation Search Results Text:

Chapter B. The Loma Prieta, California, Earthquake of October 17, 1989 - Forecasts; 1998; PP; 1550-B; The Loma Prieta, California, Earthquake of October 17, 1989: Earthquake Occurrence; Edited by Harris, Ruth A.