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Theoretical resistivity variations along stressed strike-slip faults

1976; American Geophysical Union; Volume: 81; Issue: 26 Linguagem: Inglês

10.1029/jb081i026p04909

2156-2202

David V. Fitterman,

Earthquake Detection and Analysis

A simple model of a strike-slip fault is analyzed to see if observable resistivity variations would be produced by strain accumulation. Fault displacement is found to produce only pure shear loading. Estimates of the effect of this stress system on rock resistivity are made by using existing resistivity data measured during isotropic and triaxial loading. For a model of the San Andreas fault, 50 cm of fault displacement are found to produce apparent resistivity variations of about 1%. The model considered requires long periods of time (>20 years) to produce 1% resistivity variations. This is in contrast to reported observations of large resistivity changes (>20%) developing in a period of several months before an earthquake. If more observational data confirm preearthquake resistivity changes, very different models must be considered to explain the observations.