Northridge Earthquake Damage Caused by Geologic Focusing of Seismic Waves

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 tenses 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.

Department(s)

Geosciences and Geological and Petroleum Engineering

Keywords and Phrases

Amplification; Earthquake Damage; Focal Mechanism; Northridge Earthquake 1994; Seismic Wave; Disaster; Earthquake; United States; Waveform

Geographic Coverage

Santa Monica, California

International Standard Serial Number (ISSN)

0036-8075

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2000 American Association for the Advancement of Science (AAAS), All rights reserved.

Publication Date

01 Sep 2000

Link to Full Text

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Article Location

 
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