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Multichannel sparker seismic-reflection data between Cross Sound and Dixon Entrance, offshore southeastern Alaska, collected from 2016-05-17 to 2016-06-12 during field activity 2016-625-FA

Dates

Publication Date
Start Date
2016-05-17
End Date
2016-06-12

Citation

Balster-Gee, A.F., Andrews, B.D., Brothers, D.S., ten Brink, U.S., Kluesner, J.W., and Haeussler, P.J., 2017, Multibeam and multichannel sparker seismic-reflection data between Cross Sound and Dixon Entrance, offshore southeastern Alaska, collected from 2016-05-17 to 2016-06-12 during field activity 2016-625-FA: U.S. Geological Survey data release, https://doi.org/10.5066/F7NG4PTW.

Summary

Multichannel sparker (MCS) seismic-reflection data were collected along the Queen Charlotte-Fairweather Fault between Cross Sound and Dixon Entrance, offshore southeastern Alaska from 2016-05-17 to 2016-06-12. Data were collected aboard the Alaska Department of Fish and Game R/V Medeia, and recorded using a 32 channel GeoEel digital streamer, an Applied Acoustics power supply, and a SIG SLP 790 Sparker Electrode. MCS profiles were collected coincident with multibeam data collected at higher survey speeds (5-6 knots), which reduced the MCS data quality.

Contacts

Attached Files

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2016-625-FA_index_map.jpg
“Bathymetric terrain model of Queen Charlotte Fault area, with MCS lines in black”
thumbnail 985.59 KB image/jpeg
2016-625-FA_mcs_lines_17_and_99.zip 23.17 MB application/zip

Purpose

The Queen Charlotte-Fairweather Fault (QCFF) is a major structural feature that extends more than 1,200 km from northern Vancouver Island, Canada to the Fairweather Range of southern Alaska. The fault system represents a major transform boundary that separates the Pacific Plate from the North American Plate, and in many ways, can be considered an analog “sister” fault to California’s San Andreas Fault. Early studies in the 1970s and 1980s based on historical marine geophysical data demonstrated that approximately 75 percent of the system is located offshore along the continental shelf-edge and slope, more than 20-50 km from land in eastern Gulf of Alaska. Historical seismicity records dating back to 1890 include dozens of large magnitude earthquakes, including eight events of magnitude greater than 7 and Canada’s largest earthquake on record (1949, M8.1). Finally, two recent earthquakes, a M7.8 in 2012 (“Haida Gwaii earthquake”) and M7.5 in 2013 (“Craig earthquake”) stimulated a substantial amount of scientific study of the QCFF and renewed concern over potential threats to coastal infrastructure and populations residing in southeastern Alaska and northwestern British Columbia. Survey goals included determining how fast the two sides of the fault move past each other (slip rate) and deciphering the historical movement of the fault. We also want to better understand how large earthquakes might trigger potentially dangerous underwater landslides. The purpose of this data is to provide seismic-reflection profiles primarily oriented along strike of the Queen Charlotte Fault and adjacent seafloor.

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