Premium
Further evidence of localized geomagnetic field changes before the 1974 Thanksgiving Day Earthquake, Hollister, California
Author(s) -
Davis Paul M.,
Jackson David D.,
Johnston Malcolm J. S.
Publication year - 1980
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl007i007p00513
Subject(s) - earth's magnetic field , seismology , magnetometer , geology , anomaly (physics) , geophysics , magnetic field , physics , condensed matter physics , quantum mechanics
Seven weeks prior to the M=5.1 Hollister, Calif., Thanksgiving Day earthquake of 28 November, 1974, an anomalous magnetic variation was observed at one of the magnetometers of the USGS array. The anomaly lasted for about three weeks. Recently developed methods of reducing noise on magnetic records reveal that anomalous magnetic changes occurred at about the same time at three, of the six stations analysed. Such changes have not been seen either previously or subsequently. The largest variation occurred at the two stations closest to the earthquake, but a change also occurred at a station 44 km to the south.