Whittier Narrows, California earthquake of October 1, 1987-response of elevators

The Whittier Narrows earthquake has been the first earthquake to affect a significant number and many of the same elevator systems that now conform to the more stringent code provisions introduced after the 1971 San Fernando earthquake. While the relative damage potential of the two earthquakes is not now known, much less machine room and rope damage was observed. The incidence of counterweights coming out of their guide rails was much less than it was from the San Fernando earthquake but still quite common. The performance and operation of elevator earthquake protection devices, seismic switches and counterweight derail detection devices, did not fully meet expectations but they did significantly reduce damage and the potential for injury. There was some inconsistency in the triggering of seismic switches. The seismic performance of elevators suggest that several changes to codes should be considered including a requirement to report earthquake damage.