Study of Seismic Coda Generation in Crust with Non-Uniform Scattering and Anelastic Properties
Final rept. 14 Sep 1989-14 Dec 1991
CALIFORNIA UNIV SANTA CRUZ
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A series of investigations to determine which structures affect the amplitude, duration, frequency content, and directional properties of ground motion response to explosions and earthquakes was conducted. Investigations have shown that the shallowest tens of meters are crucial in these properties of the seismic wavefield. These shallow layers are marked by great lateral heterogeneity in velocity and attenuation, and consequently we observe both vertical and lateral resonances. The scrambling of the wavefield each time it reflects from the free surface is undoubtedly very important for seismic propagation to regional distances, but we are only beginning to understand the details of this interaction.