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Seismic constraints on the architecture of the Newport‐Inglewood/Rose Canyon fault: Implications for the length and magnitude of future earthquake ruptures
Author(s) -
Sahakian Valerie,
Bormann Jayne,
Driscoll Neal,
Harding Alistair,
Kent Graham,
Wesnousky Steve
Publication year - 2017
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.983
H-Index - 232
eISSN - 2169-9356
pISSN - 2169-9313
DOI - 10.1002/2016jb013467
Subject(s) - geology , seismology , canyon , submarine pipeline , strike slip tectonics , fault (geology) , magnitude (astronomy) , slip (aerodynamics) , active fault , geomorphology , geotechnical engineering , engineering , physics , astronomy , aerospace engineering
The Newport‐Inglewood/Rose Canyon (NIRC) fault zone is an active strike‐slip fault system within the Pacific‐North American plate boundary in Southern California, located in close proximity to populated regions of San Diego, Orange, and Los Angeles counties. Prior to this study, the NIRC fault zone's continuity and geometry were not well constrained. Nested marine seismic reflection data with different vertical resolutions are employed to characterize the offshore fault architecture. Four main fault strands are identified offshore, separated by three main stepovers along strike, all of which are 2 km or less in width. Empirical studies of historical ruptures worldwide show that earthquakes have ruptured through stepovers with this offset. Models of Coulomb stress change along the fault zone are presented to examine the potential extent of future earthquake ruptures on the fault zone, which appear to be dependent on the location of rupture initiation and fault geometry at the stepovers. These modeling results show that the southernmost stepover between the La Jolla and Torrey Pines fault strands may act as an inhibitor to throughgoing rupture due to the stepover width and change in fault geometry across the stepover; however, these results still suggest that rupture along the entire fault zone is possible.