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Strain accumulation along the Cascadia Subduction Zone
Author(s) -
Murray Mark H.,
Lisowski Michael
Publication year - 2000
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 - 10.1029/1999gl011127
Subject(s) - subduction , forearc , geology , seismology , episodic tremor and slip , transition zone , slip (aerodynamics) , strain rate , strain (injury) , tectonics , geophysics , medicine , physics , materials science , metallurgy , thermodynamics
We combine triangulation, trilateration, and GPS observations to determine horizontal strain rates along the Cascadia subduction zone from Cape Mendocino to the Strait of Juan de Fuca. Shear‐strain rates are significantly greater than zero (95% confidence) in all forearc regions (26–167 nanoradians/yr), and are not significant in the arc and backarc regions. The deformation is primarily uniaxial contraction nearly parallel to Juan de Fuca‐North America plate convergence (N55°–80°E). The strain rates are consistent with an elastic dislocation model for interseismic slip with a shallow 100‐km wide locked zone and a deeper 75‐km transition zone along the entire megathrust, except along the central Oregon coast where relatively lower strain rates are consistent with 30–40 km wide locked and transition zones.