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Seismic reflection evidence for a northeast‐dipping Hayward fault near Fremont, California: Implications for seismic hazard
Author(s) -
Williams Robert A.,
Simpson Robert W.,
Jachens Robert C.,
Stephenson William J.,
Odum Jack K.,
Ponce David A.
Publication year - 2005
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 - 10.1029/2005gl023113
Subject(s) - seismology , geology , seismic hazard , fault (geology) , reflection (computer programming) , hazard , computer science , programming language , chemistry , organic chemistry
A 1.6‐km‐long seismic reflection profile across the creeping trace of the southern Hayward fault near Fremont, California, images the fault to a depth of 650 m. Reflector truncations define a fault dip of about 70 degrees east in the 100 to 650 m depth range that projects upward to the creeping surface trace, and is inconsistent with a nearly vertical fault in this vicinity as previously believed. This fault projects to the Mission seismicity trend located at 4–10 km depth about 2 km east of the surface trace and suggests that the southern end of the fault is as seismically active as the part north of San Leandro. The seismic hazard implication is that the Hayward fault may have a more direct connection at depth with the Calaveras fault, affecting estimates of potential event magnitudes that could occur on the combined fault surfaces, thus affecting hazard assessments for the south San Francisco Bay region.