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Changes of mean magnitude of Parkfield seismicity: A part of the precursory process?
Author(s) -
Wyss Max
Publication year - 1990
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/gl017i013p02429
Subject(s) - magnitude (astronomy) , san andreas fault , induced seismicity , seismology , geology , earthquake magnitude , fault (geology) , geometry , physics , mathematics , astronomy , scaling
The average magnitude of earthquakes produced along the Parkfield segment of the San Andreas fault was decreased significantly between late 1986 and late 1988 along with the seismic quiescence [Wyss et al., 1990a]. The change corresponds to an increase of the b‐value from 1.1 to 1.4. During the last year (1989) however, the average magnitude produced was approximately normal again. This same phenomenon had been identified before several other mainshocks. Therefore it may be interpreted as a precursor to the predicted Parkfield mainshock.