Seismomagnetic observation during the 8 July 1986 magnitude 5.9 North Palm Springs earthquake

M.J.S. Johnston; R.J. Mueller

doi:10.1126/science.237.4819.1201

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Seismomagnetic observation during the 8 July 1986 magnitude 5.9 North Palm Springs earthquake

M.J.S. Johnston·R.J. Mueller

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Abstract

A differentially connected array of 24 proton magnetometers has operated along the San Andreas fault since 1976. Seismomagnetic offsets of 1.2 and 0.3 nanotesla were observed at epicentral distances of 3 and 9 kilometers, respectively, after the 8 July 1986 magnitude 5.9 North Palm Springs earthquake. These seismomagnetic observations are the first obtained of this elusive but long-anticipated effect. The data are consistent with a seismomagnetic model of the earthquake for which right-lateral rupture of 20 centimeters is assumed on a 16-kilometer segment of the Banning fault between the depths of 3 and 10 kilometers in a region with average magnetization of 1 ampere per meter. Alternative explanations in terms of electrokinetic effects and earthquake-generated electrostatic charge redistribution seem unlikely because the changes are permanent and complete within a 20-minute period.

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Source-reported bounding extent: 33.88203683324397° to 33.97986652678212° latitude; -116.6027373325376° to -116.462713619128° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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BibTeX RIS

M.J.S. Johnston, R.J. Mueller. 1987. Seismomagnetic observation during the 8 July 1986 magnitude 5.9 North Palm Springs earthquake. https://doi.org/10.1126/science.237.4819.1201

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