Crustal structure beneath the Strait of Juan de Fuca and southern Vancouver Island from seismic and gravity analyses Public Deposited

http://ir.library.oregonstate.edu/concern/defaults/fj236739v

Copyrighted by American Geophysical Union.

Descriptions

Attribute NameValues
Creator
Abstract or Summary
  • Wide-angle and vertical incidence seismic data from Seismic Hazards Investigations in Puget Sound (SHIPS), gravity modeling, and seismicity are used to derive two-dimensional crustal models beneath the Strait of Juan de Fuca. The Eocene volcanic Crescent-Siletz terrane is significantly thicker than previously recognized and extends from near the surface to depths of 22 km or greater. For the northern strait, a weak midcrustal reflector, dipping east from 12- to 22-km depth, is inferred from wide-angle reflections. A stronger deeper reflector, dipping eastward from 23- to 36-km depth, is associated with the top of ‘‘reflector band E,’’ a zone of high reflectivity on coincident Multichannel Seismic (MCS) data, interpreted as a shear zone. A high-velocity zone (7.60 ± 0.2 km s⁻¹) between these reflectors is interpreted as a localized slice of mantle accreted with the overlying Crescent-Siletz terrane. For the southern strait, no deep high-velocity layer is observed and the E-band reflectivity is weaker than to the north. A strong deep reflector, interpreted as the oceanic Moho dips eastward from 35 to 42 km. Seismicity within the subducting slab occurs mainly above the inferred oceanic Moho. Gravity modeling, constrained by the wide-angle seismic models and seismicity, is consistent with the inferred large thickness of Crescent-Siletz and high-density rocks (3030 kg m⁻³) in the lower crust.
Resource Type
DOI
Date Available
Date Issued
Citation
  • Graindorge, D., G. Spence, P. Charvis, J. Y. Collot, R. Hyndman, and A. M. Tre´hu, Crustal structure beneath the Strait of Juan de Fuca and southern Vancouver Island from seismic and gravity analyses, J. Geophys. Res., 108(B10), 2484, 2003.
Keyword
Rights Statement
Publisher
Replaces
Additional Information
  • Journal of Geophysical Research
  • description.provenance : Made available in DSpace on 2010-04-26T21:36:23Z (GMT). No. of bitstreams: 1 Graindorge et al JGR 2003.pdf: 4637013 bytes, checksum: 006f86a47bc58e07dc5753ebc559a4bd (MD5) Previous issue date: 2003-10-17
  • Vol. 108 No. B10 (2003)
  • description.provenance : Submitted by David Moynihan (dmscanner@gmail.com) on 2010-04-26T20:49:35Z No. of bitstreams: 1 Graindorge et al JGR 2003.pdf: 4637013 bytes, checksum: 006f86a47bc58e07dc5753ebc559a4bd (MD5)
  • description.provenance : Approved for entry into archive by Linda Kathman(linda.kathman@oregonstate.edu) on 2010-04-26T21:36:23Z (GMT) No. of bitstreams: 1 Graindorge et al JGR 2003.pdf: 4637013 bytes, checksum: 006f86a47bc58e07dc5753ebc559a4bd (MD5)

Relationships

Parents:

This work has no parents.

Last modified

Downloadable Content

Download PDF

Items