CSMIP Strong-Motion Records from the Whittier, California Earthquake of 1 October 1987

OSMS 87-05

by A.F. Shakal, M.J. Huang, C.E. Ventura, D.L. Parke, T.Q. Cao, R.W. Sherburne, and R. Blazquez

Click on the link below for the full text:

PDF (Adobe PDF (SIZE 3.38 MB)) - Requires Adobe Acrobat Reader or other PDF viewer.


Strong-motion records were recovered from 100 stations of the California Strong Motion Instrumentation Program (CSMIP) after the earthquake of October 1, 1987 which occurred north of Whittier, California, approximately 15 km east of downtown Los Angeles. Records were recovered from 63 CSMIP ground-response stations and 38 extensively-instrumented structures. These structures include 27 buildings, eight dams, a suspension bridge, an airport control tower and a power plant. This report includes all CSMIP data from the Whittier earthquake and supersedes the brief compilation distributed immediately after the earthquake (CDMG, 1987). In addition to the records recovered by CSMIP, records were also recovered by the U.S. Geological Survey, the University of Southern California, and other agencies. In total this set of data will be the largest ever recorded from an earthquake, exceeding that recovered in the 1971 San Fernando earthquake.

The estimated earthquake location and magnitude are (Caltech):
           Epicenter: 34.058N, 118.075W. Depth: 9 km.
           Origin Time: 14:42:20 GMT (07:42:20 PDT), 1 October 1987M
           Magnitude: 6.1 ML

Damage was moderate over a broad area and extensive in certain localized areas such as downtown Whittier. Damage studies by other organizations are still underway at this time. A preliminary report completed by the engineering firm EQE, Inc. (EQE, 1987) provides a good, early overview of damage to various types of construction in the Los Angeles area. A preliminary report by Burdick and others (1987) reviewed damage to power generating facilities. EQE estimates that the total damage will exceed $100 million.