Seismomagnetic effects



Local changes in the earth's magnetic field that are associated with active faults have long been viewed as offering a potential method of analyzing earthquakes. Considerable efforts have been made to determine the effects theoretically and, in the field, to develop a sensitive method of identifying characteristic stress patterns. In particular, if related magnetic changes can be identified before an earthquake, the so-called seismomagnetic effect could be useful in earthquake prediction. After several years of observing magnetic changes whose magnitudes seem to have been constantly reevaluated in the light of more sensitive measurements, Hao, Hastie, and Stacey (Physics of Earth and Planetary Interiors, 28, 129, 1982) recently examined the theory and concluded that actual effects are probably a lot weaker than had been previously thought.