Preliminary Summary of CDMG Strong-Motion Records from the 2 May 1983 Coalinga, California Earthquake

OSMS 83-5.2

by A.F. Shakal and R.D McJunkin

Click on the link below for the full text:

PDF (Adobe PDF (SIZE 1.1 MB)) - Requires Adobe Acrobat Reader or other PDF viewer.


A moderate-size earthquake occurred at 16:43 (PDT) on May 2, 1983 approximately 13 km northeast of Coalinga, on Anticline Ridge in Fresno County, California (Figure 1). Preliminary epicentral location estimates by the USGS and UC Berkeley put the epicenter near 36.25N, 120.30W, at a depth between 9 and 11 km. Berkeley estimates the magnitude to be 6.5 (ML) with an origin time of 23:42:38.5 UTC. To date, no tectonic surface rupture from a causative fault has been identified.

The main shock was felt widely throughout the state. It is the largest earthquake to occur in continental California since the San Fernando earthquake of 9 February 1971. The event destroyed many of the older buildings in the downtown business district of Coalinga and many homes throughout the area.

This report summarizes CDMG strong-motion accelerograph records recovered from the 2 May 1983 Coalinga earthquake. In order to allow for early distribution of CDMG strong-motion data from the earthquake, this report is limited to a summary of the data. The preliminary nature of this report makes the data presented here subject to later revision; however, reasonable precautions have been taken to ensure the accuracy of the data.