This report summarizes the data from near-in strong-motion accelerograph stations operated by the U.S. Geological Survey in the Imperial Valley of California at the time of the October 15, 1979 Imperial Valley earthquake. The purpose of this report is to alert others as to the nature of the strong-motion data that is available from this event. In order to provide the information in a timely manner, the report has been limited to a summary of the data. A similar preliminary report of strong-motion data collected by the Office of Strong-Motion Studies of the California Division of Mines and Geology has already been issued. A more complete report of all of the strong ground motion data is contemplated. This will require the cooperation of all of the agencies in both the U.S. and Mexico that operate strong-motion instruments in the region. A report on the processing of the data from near-in stations is in preparation. The moderate-size (magnitude 6.4) October 15, 1979 Imperial Valley earthquake was instrumentally located on the Imperial fault approximately 25 km southeast of El Centro, California. This location is approximately the same as that of the 1940 Imperial Valley earthquake.
