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The spatio‐temporal variation of seismicity before the 1971 San Fernando Earthquake, California
Author(s) -
Ishida Mizuho,
Kanamori Hiroo
Publication year - 1977
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/gl004i008p00345
Subject(s) - induced seismicity , epicenter , seismology , geology , foreshock , period (music) , aftershock , physics , acoustics
The spatio‐temporal variation of seismicity prior to the 1971 San Fernando, California, earthquake is studied for the area within 35 km of the epicenter. During the period from 1932 to 1961, the seismicity in this area was relatively low and random. A remarkable NE‐SW trending alignment of activity occurred during the period from 1961 to 1964, the period corresponding to the inferred onset of the Palmdale uplift. During the period from 1965 to 1968, the seismicity around the epicentral area became extremely low; no event was located within 13 km from the epicenter. During the period from 1969 to the occurrence of the San Fernando earthquake, activity around the epicentral area increased. This activity may be considered to be foreshock activity in a broad sense.