Local Geomagnetic Events Associated with Displacements on the San Andreas Fault

See allHide authors and affiliations

Science  06 Oct 1967:
Vol. 158, Issue 3797, pp. 116-118
DOI: 10.1126/science.158.3797.116


The piezomagnetic properties of rock suggest that a change in subsurface stress will manifest itself as a change in the magnetic susceptibility and remanent magnetization and hence the local geomagnetic field. A differential array of magnetometers has been operating since late 1965 on the San Andreas fault in the search for piezomagnetic signals under conditions involving active fault stress. Local changes in the geomagnetic field have been observed near Hollister, California, some tens of hours preceding the onset of abrupt creep displacement on the San Andreas fault.