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Two-dimensional compressional wave velocity structure under San Francisco Volcanic Field, Arizona, from teleseismic P residual measurements

D.A. Stauber
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Abstract

A low compressional-wave velocity region in the midcrust below the San Francisco Mountain stratovolcano, Arizona, has been detected by the teleseismic P residual technique. This region is approximately 6 km wide, lies between elevations of 9 km and 34 km below sea level, and has a compressional velocity reduction of more than 6% with respect to the surrounding rocks. Several mechanisms are found to be quantitatively sufficient to produce such a feature. These include (1) a cool silicic pluton enclosed in a more mafic crust, (2) high temperature (near but below the solidus) in a quartz-bearing rock in the low-velocity region, (3) high density of water-filled cracks having pore pressures nearly equal to lithostatic pressure, and (4) the presence of melt, either in intergranular pores or in crystal-poor dikes.

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D.A. Stauber. 2012-09-20. Two-dimensional compressional wave velocity structure under San Francisco Volcanic Field, Arizona, from teleseismic P residual measurements. https://doi.org/10.1029/jb087ib07p05451

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