The Victoria Accelerogram for the 1980 Mexicali Valley Earthquake

Abstract

Most of the remarkable digital strong motion accelerogram from the June 9, 1980 Mexicali Valley earthquake (M _w = 6.4) has been recovered by careful analysis. Peak horizontal accelerations (.98g, .87g) and duration were similar to the values for the recent Superstition Hills earthquake. The vertical accelerogram clipped the 1g instrument several times. The records provide an important example of near fault accelerations from a second earthquake in the deep sediments of the Imperial Mexicali Valley (the other being the records from the 1979 Imperial Valley earthquake). The 1980 accelerograms are important because they were not affected by foundation filtering, as were the records for the Imperial Valley 1940 earthquake, and because they illustrate the damaging near-source, intermediate frequency velocity pulse associated with passage of the rupture front.