National Geophysical Data Center
MULTICHANNEL SEISMIC-REFLECTION PROFILES
Data Announcement 84-MGG-08
Approximately 1,020 km of 24-channel seismic reflection profiles are now available for offshore Washington and Oregon. The profiles were collected by the U.S. Geological Survey (USGS) on the USGS Research Vessel S.P. LEE during the spring of 1977 (USGS Open File Report 84-5).* A sound source of five airguns was used with a 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 by a Marconi integrated satellite-Doppler sonar navigation system.
The seismic reflection record lengths vary from 6 to 7 sec, depending on water depth, to obtain 5 to 6 sec of data below the seafloor. The data have been processed in a sequence of editing, demultiplexing, velocity analysis, stacking, deconvolution filtering, and graphically displayed on an electrostatic plotter.
* "Multichannel Seismic-Reflection Profiles Collected in 1977 in the Eastern Pacific Ocean Off of the Washington/Oregon Coast,: Dennis M. Mann and Parke D. Snavely, U.S. Geological Survey, Menlo Park, CA USGS Open File Report 84-5.