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A strain anomaly near the southern end of the San Andreas Fault, Imperial Valley, California
Author(s) -
Reilinger Robert
Publication year - 1985
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/gl012i009p00561
Subject(s) - san andreas fault , geology , seismology , fault (geology) , normal fault , geodetic datum , anomaly (physics) , transform fault , geodesy , physics , condensed matter physics
Repeated first‐order leveling surveys conducted by the National Geodetic Survey (NGS) in 1972, 1974, 1976, 1978, and 1981 provide evidence of contemporary relative uplift near the junction of the San Andreas fault and the Brawley Seismic Zone. Uplift, which extends over a distance of about 5 km where crossed by the leveling line, apparently developed progressively between 1972 (possibly before) and 1978. Maximum relative uplift during this period reached 58 ± 4 mm. This spatially and temporally coherent pattern of uplift was interrupted between 1978 and 1981 possibly as a result of the 1979, M6.6 Imperial Valley earthquake. While the cause of the observed uplift is unknown, given the location, one interpretation is that it represents a zone of concentrated strain possibly associated with fault activity.