Archive of Digital Boomer Subbottom Data Collected During USGS Cruises 99FGS01 and 99FGS02 Offshore Southeast and Southwest Florida, July and November, 1999

The USGS Saint Petersburg Coastal and Marine Science Center (SPCMSC) - St. Petersburg, FL, assigns a unique identifier to each cruise or field activity. For example, 99FGS01 and 99FGS02 tells us the data were collected in 1999 for the Florida Geological Survey (FGS) cooperative agreement and the data were collected during the first and second field activities for that project in that calendar year. Refer to <http://walrus.wr.usgs.gov/infobank/programs/html/definition/activity.html> for a detailed description of the method used to assign the cruise ID.The boomer subbottom processing system consists of an acoustic energy source that is made up of capacitors charged to a high voltage and discharged through a transducer in the water. The transducer is towed on a sled floating on the water surface and when discharged emits a short acoustic pulse, or shot, that propagates through the water column and shallow stratigraphy below. The acoustic energy is reflected at density boundaries (such as the seafloor or sediment layers beneath the seafloor), detected by the receiver (hydrophone streamer), and recorded by a PC-based seismic acquisition system. This process is repeated at timed intervals (for example, 0.5 s) and recorded for specific intervals of time (for example, 100 ms). In this way, a 2-D vertical image of the shallow geologic structure beneath the ship track is produced.An Applied Acoustic Engineering CSP 300 provided 300 Joules of energy per shot. Reflected energy was received by a Innovative Transducers, Inc. (ITI) ST-5 10-channel streamer and recorded by Triton Elics International, Inc. (TEI) Delph Seismic v. 1.36 acquisition software. The streamer contains 10 hydrophones evenly spaced every 0.60 m. The streamer was positioned directly behind the research vessel (parallel to the boomer sled), with a lateral separation of approximately 14 m (99FGS01) and 24 m (99FGS02). Refer to figure 2 included with this archive for a diagram of the acquisition geometries. The sample frequencies of the data were 240-2400 Hz and 8000 Hz, and record length was 100 ms. The shot spacing was highly variable; however, based on survey speeds of 3 knots and a shot rate of every 1 s, shot spacing was about 1.54 m.The unprocessed seismic data are stored in SEG Y rev. 0, integer, Motorola format, which is a standard digital format that can be read and manipulated by most seismic processing software packages (Barry and others, 1975). The SEG Y formatted trace files have a .TRA extension. The printable profiles provided here are GIF images that were filtered and gained using Seismic Unix software.