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Mechanical models favor a ramp geometry for the Ventura‐pitas point fault, California
Author(s) -
Marshall Scott T.,
Funning Gareth J.,
Krueger Hannah E.,
Owen Susan E.,
Loveless John P.
Publication year - 2017
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 - 10.1002/2016gl072289
Subject(s) - geology , geodetic datum , slip (aerodynamics) , fault (geology) , geometry , geodesy , seismology , global positioning system , mathematics , physics , computer science , telecommunications , thermodynamics
Recent investigations have provided new and significantly revised constraints on the subsurface structure of the Ventura‐Pitas Point fault system in southern California; however, few data directly constrain fault surfaces below ~6 km depth. Here, we use geometrically complex three‐dimensional mechanical models driven by current geodetic strain rates to test two proposed subsurface models of the fault system. We find that the model that incorporates a ramp geometry for the Ventura‐Pitas Point fault better reproduces both the regional long term geologic slip rate data and interseismic GPS observations of uplift in the Santa Ynez Mountains. The model‐calculated average reverse slip rate for the Ventura‐Pitas Point fault is 3.5 ± 0.3 mm/yr, although slip rates are spatially variable on the fault surface with > 8 mm/yr predicted on portions of the lower ramp section at depth.