Publication Date:
2022-05-25
Description:
Author Posting. © American Geophysical Union, 2018. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 45 (2018): 11,095-11,103, doi:10.1029/2018GL079519.
Description:
Great subduction zone earthquakes vary considerably in the updip extent of megathrust rupture. It is unclear if this diversity reflects variations in interseismic strain accumulation owing to the limited number of subduction zones with seafloor monitoring. We use a borehole seismic‐geodetic observatory installed at the updip end of the Cascadia fault offshore Vancouver Island to show that the megathrust there does not appear to slip in triggered tremor or slow‐slip events when subjected to moderate dynamic stress transients. Borehole tilt and seismic data from recent teleseismic M7.6–8.1 earthquakes demonstrate a lack of triggered slow slip above the Mw 4.0 level and an absence of triggered tremor despite shear‐stress transients of 1–10 kPa that were sufficient to trigger tremor on the downdip end of the interface. Our observations are most consistent with a model in which the Cascadia fault offshore Vancouver Island is locked all the way to the trench.
Description:
NSF Grant Numbers: OCE‐1259243, OCE‐1259718;
W. M. Keck Foundation
Description:
2019-04-27
Keywords:
Cascadia subduction zone
;
Seafloor geodesy
;
Seismic tremor
Repository Name:
Woods Hole Open Access Server
Type:
Article
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