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Variations in creep rate along the Hayward Fault, California, interpreted as changes in depth of creep
Author(s) -
Simpson R. W.,
Lienkaemper J. J.,
Galehouse J. S.
Publication year - 2001
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 - 10.1029/2001gl012979
Subject(s) - creep , geology , fault (geology) , seismology , san andreas fault , moment (physics) , moment magnitude scale , seismic moment , geodesy , geometry , materials science , physics , mathematics , classical mechanics , scaling , composite material
Variations in surface creep rate along the Hayward fault are modeled as changes in locking depth using 3D boundary elements. Model creep is driven by screw dislocations at 12 km depth under the Hayward and other regional faults. Inferred depth to locking varies along strike from 4–12 km. (12 km implies no locking.) Our models require locked patches under the central Hayward fault, consistent with a M6.8 earthquake in 1868, but the geometry and extent of locking under the north and south ends depend critically on assumptions regarding continuity and creep behavior of the fault at its ends. For the northern onshore part of the fault, our models contain 1.4–1.7 times more stored moment than the model of Bürgmann et al. [2000]; 45–57% of this stored moment resides in creeping areas. It is important for seismic hazard estimation to know how much of this moment is released coseismically or as aseismic afterslip.