Archive of Digital Boomer Seismic reflection Data Collected Offshore East-Central Florida During USGS Cruise 00FGS01, July 14-22, 2000

The USGS St. Petersburg Coastal and Marine Science Center in Florida, assigns a unique identifier to each cruise or field activity. For example, 00FGS01 tells us the data were collected in 2000 for the Florida Geological Survey (FGS) cooperative agreement and the data were collected during the first field activity 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 plate is an acoustic energy source that consists of capacitors charged to a high voltage and discharged through a transducer in the water. The transducer is towed on a sled at the sea surface and when discharged emits a short acoustic pulse, or shot, that propagates through the water and sediment column. The acoustic energy is reflected at density boundaries (such as the seafloor or sediment layers beneath the seafloor), detected by the receiver, and recorded by a PC-based seismic acquisition system. This process is repeated at timed intervals (for example, 1 second) and recorded for specific intervals of time (for example, 200 milliseconds). In this way, a 2D vertical image of the shallow geologic structure beneath the ship track is produced. An Applied Acoustic Engineering CSP 300 power supply provided 100 joules per shot. Reflected energy was received by an Innovative Transducers, Inc. (ITI) ST-5 10-channel streamer and recorded by Triton Elics International, Inc. (TEI) Delph Seismic acquisition software. The streamer contains 10 hydrophones evenly spaced every 2 feet. Only data received by elements 4-8 were summed. Refer to the handwritten FACS overview log included in this archive for a diagram of the acquisition geometry. The sample frequency of the data is 8-12 kilohertz. Record length for all tracklines is 200 milliseconds. The shot rate was every 1 second. Shot spacing for each line is about 2.5 meters. The unprocessed seismic data are stored in SEG-Y, 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. Additional recording parameters for each trace file can also be found in the .PAR file associated with each .TRA file. However, the .PAR and .PLN files included here are only needed to process or display the data with TEI Delph Seismic software. Also provided are example Seismic Unix scripts that allow the user to extract navigation fixes from the SEG-Y headers, along with a fix for every 500 shots, and produce a filtered and gained GIF image of each profile. The navigation information was recorded in two locations in the original SEG-Y headers. The navigation in the defined fields is only accurate to 1 second of arc or approximately 31 meters. The navigation stored in the undefined fields and used here to produce the trackline maps and navigation files and is accurate to the degree of the GPS receiver or 3-5 meters. The navigation files provided here were extracted from the undefined fields using Delph Seismic software.