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Future Cascadia megathrust rupture delineated by episodic tremor and slip
Author(s) -
Chapman James S.,
Melbourne Timothy I.
Publication year - 2009
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 - 10.1029/2009gl040465
Subject(s) - episodic tremor and slip , geology , seismology , slip (aerodynamics) , subduction , tectonics , engineering , aerospace engineering
A suite of 15 episodic tremor and slip events imaged between 1997 and 2008 along the northern Cascadia subduction zone suggests future coseismic rupture will extend to 25 km depth, or ∼60 km inland of the Pacific coast, rather than stopping offshore at 15 km depth. An ETS‐derived coupling profile accurately predicts GPS‐measured interseismic deformation of the overlying North American plate, as measured by ∼50 continuous GPS stations across western Washington State. When extrapolated over the 550‐year average recurrence interval of Cascadia megathrust events, the coupling model also replicates the pattern and amplitude of coseismic coastal subsidence inferred from previous megathrust earthquakes here. For only the Washington State segment of the Cascadia margin, this translates into an M w = 8.9 earthquake, with significant moment release close to its metropolitan centers.