Egill Hauksson, Crustal structure and seismicity distribution adjacent
the Pacific and North American plate boundary in southern California,
Geophys. Res., 105, 13,875-13,905, 2000.
This is the Vp/Vs ratio.
The initial view is approximately to the north.
The values are linearly interpolated in depth onto a 1 km grid. The figure
is plotted with a vertical exaggeration of about 5.