Report

Northridge Earthquake Damage Caused by Geologic Focusing of Seismic Waves

Science  08 Sep 2000:
Vol. 289, Issue 5485, pp. 1746-1750
DOI: 10.1126/science.289.5485.1746

You are currently viewing the abstract.

View Full Text

Via your Institution

Log in through your institution

Log in through your institution


Abstract

Despite being located 21 kilometers from the epicenter of the 1994 Northridge earthquake (magnitude 6.7), the city of Santa Monica experienced anomalously concentrated damage with Mercalli intensity IX, an intensity as large as that experienced in the vicinity of the epicenter. Seismic records from aftershocks suggest that the damage resulted from the focusing of seismic waves by several underground acoustic lenses at depths of about 3 kilometers, formed by the faults that bound the northwestern edge of the Los Angeles basin. The amplification was greatest for high-frequency waves and was less powerful at lower frequencies, which is consistent with focusing theory and finite-difference simulations.

  • * To whom correspondence should be addressed. E-mail: pdavis{at}ess.ucla.edu

View Full Text