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A Geo-referenced 3D model of the Juan de Fuca Slab and associated seismicity

January 1, 2011

We present a Geographic Information System (GIS) of a new 3-dimensional (3D) model of the subducted Juan de Fuca Plate beneath western North America and associated seismicity of the Cascadia subduction system. The geo-referenced 3D model was constructed from weighted control points that integrate depth information from hypocenter locations and regional seismic velocity studies. We used the 3D model to differentiate earthquakes that occur above the Juan de Fuca Plate surface from earthquakes that occur below the plate surface. This GIS project of the Cascadia subduction system supersedes the one previously published by McCrory and others (2006). Our new slab model updates the model with new constraints. The most significant updates to the model include: (1) weighted control points to incorporate spatial uncertainty, (2) an additional gridded slab surface based on the Generic Mapping Tools (GMT) Surface program which constructs surfaces based on splines in tension (see expanded description below), (3) double-differenced hypocenter locations in northern California to better constrain slab location there, and (4) revised slab shape based on new hypocenter profiles that incorporate routine depth uncertainties as well as data from new seismic-reflection and seismic-refraction studies. We also provide a 3D fly-through animation of the model for use as a visualization tool.

Publication Year 2011
Title A Geo-referenced 3D model of the Juan de Fuca Slab and associated seismicity
DOI 10.3133/ds633
Authors J.L. Blair, P.A. McCrory, D. H. Oppenheimer, F. Waldhauser
Publication Type Report
Publication Subtype USGS Numbered Series
Series Title Data Series
Series Number 633
Index ID ds633
Record Source USGS Publications Warehouse
USGS Organization Earthquake Science Center; Menlo Park Science Center