Davis PM, Rubinstein JL, Liu KH, Gao SS, Knopoff L
Department of Earth and Space Sciences, University of California, Los Angeles, CA 90095-1567, USA. Department of Geology, Kansas State University, Manhattan, KS 66506-3201, USA. Institute of Geophysics and Planetary Physics and Department of Physic.
Science. 2000 Sep 8;289(5485):1746-50. doi: 10.1126/science.289.5485.1746.
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.
尽管圣莫尼卡市距离1994年北岭地震（震级6.7）的震中21公里，但该市却遭受了异常集中的破坏，烈度达到麦加利烈度IX级，与震中附近所经历的烈度一样大。余震的地震记录表明，破坏是由几个位于约3公里深处的地下声学透镜对地震波的聚焦造成的，这些透镜是由界定洛杉矶盆地西北边缘的断层形成的。高频波的放大效应最为显著，而低频波的放大效应则较弱，这与聚焦理论和有限差分模拟结果一致。
