USGS CMG T-1-98-PS Metadata

See also T-2-98-PS (Tully) & T-3-98-PS (land)

   From February 27, 1998 Coastal and Marine Geology Bulletin

   SHIPS IS ON ITS WAY!
      Late this past week 5 48-foot trucks and some smaller cargo carriers left 
  Marfac
   loaded with compressors, generators, airguns, and myriad
      other gear, all of which is destined for the SHIPS program in Seattle. 
  Another
   truck left Texas with the 50-ton multichannel streamer. If all
   goes well, nearly 100 tons of mechanical and electrical equipment will be
   installed on the University of Washington's 275-foot research
   vessel, Thomas G. Thompson. This ship will be joined by the 240-foot Canadian
   research ship, John P. Tully, and the two ships will conduct
   intricate seismic experiments in the Puget Sound region. While airguns are
   discharged behind the Thompson, the resulting seismic waves
      will be recorded by the Tully as well as by 250 temporary seismometers that 
  will
   be scattered around the region. About 50 fixed earthquake
      seismometers will also record these data. This survey is the most complex 
  ever
   mounted by the USGS to investigate earthquake hazards in an
      urban setting. Cooperating institutions include the U.S. and Canadian 
  Geological
   Surveys and six universities. The US Navy lent us critical
   infra-red gear, which was almost diverted to the Iraq conflict, and MMS
   contributed funds toward studying marine mammals. Funding comes
      almost entirely from within the USGS; the external NEHRP, Urban Hazards, and the
   Coastal and Marine Programs all contributed. Coastal and
      Marine has the honor of having chipped in the greatest share. Permission to 
  use
   airguns in Puget Sound and the Straits of Juan de Fuca and
   Georgia, which are home to many marine mammals, took almost a year to obtain.
   Part of the stipulations in the permit are that when the
      airguns are operating, marine mammal biologists must remain vigilant aboard 
  both
   survey ships and aboard an aircraft. Eleven biologists will
   work closely with geologists to obtain seismic data while minimizing harm to
   marine life. These biologists have responsibility for shutting
      off the array whenever a marine mammal enters a specific zone around the airguns
   where it might suffer hearing damage. The size of the
   protective zone varies with mammal species, hence the need for expert
   assistance. With close cooperation, we will obtain three-dimensional
   seismic data and information on the behavior of marine mammals in response to
   airgun signals. The data about mammals will help us and
   other groups plan the next airgun surveys; the seismic data will help city
   planners allocate scarce funds for seismic strengthening of
   important infrastructure. Crew from Marfac CMG and EQ leave early next week.

   Mike Fisher