Seismicity of the Earth 1900-2013 offshore British Columbia-southeastern Alaska and vicinity

Open-File Report 2010-1083-O
By: , and 

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Abstract

The tectonics of the Pacific margin of North America between Vancouver Island and south-central Alaska are dominated by the northwest motion of the Pacific plate with respect to the North America plate at a velocity of approximately 50 mm/yr. In the south of this mapped region, convergence between the northern extent of the Juan de Fuca plate (also known as the Explorer microplate) and North America plate dominate. North from the Explorer, Pacific, and North America plate triple junction, Pacific:North America motion is accommodated along the ~650-km-long Queen Charlotte fault system. Offshore of Haida Gwaii and to the southwest, the obliquity of the Pacific:North America plate motion vector creates a transpressional regime, and a complex mixture of strike-slip and convergent (underthrusting) tectonics. North of the Haida Gwaii islands, plate motion is roughly parallel to the plate boundary, resulting in almost pure dextral strike-slip motion along the Queen Charlotte fault. To the north, the Queen Charlotte fault splits into multiple structures, continuing offshore of southwestern Alaska as the Fairweather fault, and branching east into the Chatham Strait and Denali faults through the interior of Alaska. The plate boundary north and west of the Fairweather fault ultimately continues as the Alaska-Aleutians subduction zone, where Pacific plate lithosphere subducts beneath the North America plate at the Aleutians Trench. The transition is complex, and involves intraplate structures such as the Transition fault. The Pacific margin offshore British Columbia is one of the most active seismic zones in North America and has hosted a number of large earthquakes historically.

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Additional publication details

Publication type Report
Publication Subtype USGS Numbered Series
Title Seismicity of the Earth 1900-2013 offshore British Columbia-southeastern Alaska and vicinity
Series title Open-File Report
Series number 2010-1083
Chapter O
DOI 10.3133/ofr20101083O
Year Published 2014
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Geologic Hazards Science Center
Description 1 map sheet: 38.77 x 27.01 inches
Country Canada;United States
State Alaska;British Columbia
Scale 3500000
Online Only (Y/N) Y
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