PREDOMINANT MOTION OF THE LOS-ANGELES SEDIMENTARY BASIN

Predominant motion of the Los Angeles sedimentary basin is investigated theoretically and experimentally. Theoretical investigation of the predominant periods of the basin is done through use of an indirect boundary integral equation method. Sedimentary basis is modeled as a single dipping layer embedded within a baserock half-space. The basin is subjected to vertically incident plane harmonic SH, P, and SV waves. For each of the incident waves the fundamental period of the predominant motion of the basin is calculated numerically. In experimental part of investigation long period microtremor recordings were made along two characteristic sections at eleven observation sites of the basin. From these measurements the fundamental period of the predominant motion of the basin is identified. Comparison of the experimental and theoretical periods of predominant motion show that the predominant motion of the basin is associated with corresponding SV-wave resonance.