HR: 13:30h
AN: GP23A-01 INVITED     [Abstracts]
TI: Natural Magnetic Fields Preceding the Loma Prieta Earthquake that Damaged San Francisco in October 1989
AU: * Campbell, W H
EM: bcampbel@colorado.edu
AF: Solar-Terrestrial Physics Division, NGDC/NOAA, 3030 Galena Way , Boulder, CO 80305 United States
AB: Available records of the magnetic indices Dst and ap together with USGS standard observatory recordings of the 1-min fields are examined for the time preceding the Loma Prieta earthquake that severely damaged the San Francisco area in October, 1989. The results indicate that a 1990 report claiming the existence of a ULF geomagnetic field precursor signal foretelling a nearby earthquake is very likely false. The observatory study shows that the ULF signal was not local but rather widespread throughout the western United States and therefore expected to be of solar-terrestrial disturbance origin. The two planetary activity indices support this conclusion.
DE: 1513 Geomagnetic excursions
DE: 1530 Rapid time variations
DE: 2722 Forecasting
DE: 7223 Seismic hazard assessment and prediction
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2005 Joint Assembly