National Centers for Environmental Information (NCEI)

MULTICHANNEL SEISMIC-REFLECTION PROFILES
Eastern Gulf of Alaska
USGS Open File Report 84-6*

Data Announcement 84-MGG-17

     Approximately 2,492 km of 24-channel seismic-reflection profiles for the Eastern Gulf of Alaska. The profiles were collected by the U.S. Geological Survey (USGS) on the USGS Research Vessel S.P. LEE during the summer of 1977 (USGS Open File Report 84-6).* A sound source of five airguns was used with a volume of 1,326 cu. in. of air compressed to approximately 1,950 psi. The recording system consisted of a 24-group streamer, 2,400 m long and a GUS (Global Universal Science) model 4200 recording instrument. Shots were fired every 50 m with a group interval of 100 m. A 2-msec sampling rate was used in the field. The data were later desampled to 4 msec during the demultiplexing process. Navigational control for the survey was obtained with a Marconi integrated satellite-Doppler sonar navigation system.

     The seismic-reflection record lengths vary from 6 to 10 sec, depending on water depth, to obtain a 5-to 6-sec penetration below the seafloor. The data have been processed in a sequence of editing, demultiplexing, velocity analysis, stacking, and deconvolution filtering; and graphically displayed on an electrostatic plotter. The USGS, Department of Interior, has provided these data to the National Geophysical Data Center (NGDC) (now the National Centers for Environmental Information (NCEI)) for public dissemination. ------------------------
* "Multichannel Seismic-Reflection Profiles Collected in 1977 in the Eastern Gulf of Alaska," Dennis M. Mann and Terry R. Bruns, U.S. Geological Survey, Menlo Park, CA USGS Open Report 84-6.

DATA AVAILABILITY

       Electrostatically plotted profiles which have been deconvolved and filtered after stacking:

         34 lines available in plastic sepia, paper sepia, and blackline.

         1 navigation tape, 9-track, 1600 bpi, ASCII. This is also available on CD-ROM.

         1 trackline map available in plastic sepia, paper sepia, and blackline.