Figure 18

Three-dimensional representation of full waveform seismograms computed in a simple 3-D model of the San Andreas fault at Middle Mountain. The model includes a narrow, tabular low velocity zone at the fault, and models the large-scale crustal contrast between the Salinian and Franciscian basement rocks across the fault. The data cube shows the seismic wave amplitudes on three planar surfaces in the 3-D model. The planes are marked by the reference lines on the cube, and are located at the earth's surface (top surface), in the plane of the fault (right side) and on a plane perpendicular to the fault that passes through the buried source (front surface). This high-resolution model (40 m grid spacing, 20 Hz frequency resolution) clearly shows the development of fault zone guided waves in the fault zone. Figure by Martin Karrenbach, University of Karlsruhe.