2011 Gulf of Alaska

Gulf of Alaska, showing planned tracklines, Extended Continental Shelf Project 2011 Gulf of Alaska cruise. Abbreviations: MCS, multichannel seismic; OBS, ocean-bottom seismometer; NM, nautical mile; EEZ, Exclusive Economic Zone.

Gulf of Alaska, showing planned tracklines, Extended Continental Shelf Project 2011 Gulf of Alaska cruise. Abbreviations: MCS, multichannel seismic; OBS, ocean-bottom seismometer; NM, nautical mile; EEZ, Exclusive Economic Zone. Click image for larger version or download a hi-res pdf. Credit: USGS

R/V Marcus G. Langseth spent 20 days from June 6 – 26, 2011 in the Gulf of Alaska collecting multichannel seismic reflection and refraction data. The mission focused on structures and processes that control the distribution of sediment, aspects that are important for delineating the extended continental shelf (ECS) using the sediment thickness formula.  Norseman II rendezvoused with Langseth, to support deployment of 15 ocean-bottom seismometers on two lines. The chief scientists were Dr. Ginger Barth, United States Geological Survey (USGS), and Dr. Sean Gulick, University of Texas Institute of Geophysics. Five protected-species observers were onboard Langseth, and two scientists made regional background observations of marine species from the Norseman II.  Additional data collection included gravity, magnetic, CHIRP sonar, multibeam bathymetry, seismic oceanography, and water column temperature and salinity measurements.  A 2005 mission began bathymetric mapping in the Gulf of Alaska.