Comparison of 1989 Loma Prieta earthquake damage to mapped lineaments along the range front of the Santa Cruz Mountains, California

Abstract

Damage to public infrastructure at or below the ground surface (streets, curbs, and water and gas lines) in southwestern Santa Clara Valley, California, associated with the 1989 Loma Prieta earthquake, is used to support the assertion that the series of photointerpreted lineaments are tectonic in origin and related to long-term reverse faulting along the range front of the Santa Cruz Mountains. We quantitatively analyze whether the photointerpreted lineaments are spatially correlated with earthquakeinduced damage by examining whether the damage was located preferentially closer to the mapped lineaments than to a spatially random set of points. The analysis confi rms that damage related to the Loma Prieta earthquake is located preferentially close to mapped lineaments. This result supports the assertion that the lineaments have a tectonic origin related to range-front faulting along the Santa Cruz Mountains, and that their presence may be related to primary fault rupture, spatially focused shaking damage, or slip triggered by strong motion induced by nearby faults.