Preliminary report on the use of digital strong motion recorders in the Mexicali Valley, Baja California

Abstract

Abstract A network of 12 digital strong motion accelerographs has been operating in the Mexicali Valley, Baja California, Mexico, since 1978. The instruments have triggered reliably, except for external problems, such as power failures and site harassment. Data from two important earthquakes and several smaller shocks have been recovered. These data have a noise level which appears to be no worse than that on digitized records from analog strong motion accelerographs, in spite of design errors which resulted in increased instrumental noise levels in several of the accelerographs (these design errors have recently been corrected). Digital recording of strong motion promises great advantages over analog recording through recovery of the initial motions, greater dynamic range, rapid playback, and lower equivalent instrumental noise level because manual or semiautomatic digitization of an analog record is not required.