The June 28, 1991 Sierra Madre California earthquake

  • R. Shepherd University of California, Irvine, USA


Although not a major event compared with the 1989 Loma Prieta one, the Sierra Madre earthquake of June 28, 1991 served to remind Californians that seismic hazard mitigation programs require constant monitoring to ensure their effectiveness and that the stock of precode, high risk buildings continues to prove difficult to eliminate. In this paper aspects of damage suffered by constructed facilities are summarized, specific examples of the behaviour of selected structures are reported and ongoing problems with earthquake insurance and the enforcement of state law requiring cities to identify buildings particularly prone to earthquake damage are described.


Los Angeles Municipal Code, "Earthquake Hazard Reduction in Existing Buildings", Ordinance No. 154, 807 approved 1981.

Shepherd, R., "The October 1, 1987 Whittier Narrows Earthquake", Bulletin of the New Zealand National Society for Earthquake Engineering, 1987, 20, 4, 225-263. DOI:

"Loma Prieta Earthquake Reconnaissance Report", Earthquake Spectra, 1990, 6 (supplement), 127-149. DOI:

CSMIP strong-Motion Records from the Sierra Madre, California Earthquake of June 28, 1991; California Department of Conservation, Division of Mines and Geology, Sacramento; Report OSMS 91-02, 1991.

How to Cite
Shepherd, R. (1991). The June 28, 1991 Sierra Madre California earthquake . Bulletin of the New Zealand Society for Earthquake Engineering, 24(4), 279-286.