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National Centers for Environmental Information (NCEI)

University of Texas-Institute for Geophyics


Offshore Nicaragua and Panama

Data Announcement 86-MGG-22

Approximately 2,500 km of underway geophysical data, including 430 km of 24-channel common depth point (CDP) seismic-reflection data for purchase from the National Geophysical Data Center (NGDC) (now the National Centers for Environmental Information (NCEI)). The data were collected in the eastern equatorial Pacific Ocean offshore Nicaragua and Panama by the University of Texas Institute for Geophysics during R/V IDA GREEN cruise 24, Leg 7, in July 1977. The data have been made available by the University of Texas to NGDC (now NCEI) for public dissemination.

The CDP seismic data were collected from a 24-channel, 2,280-m array using 3/4-pound of explosive charges and 3 to 4 BOLT Model MAG-4200 airguns pressured to 350 psi. The recording group interval varied from 45.7 m on the NIC line to 91.4 m on the PN-2 line. Shot distance was approximately 45 to 50 m. Record length was 12 sec at a sample rate of 4 m/sec and the vertical scale is 2.5 in./sec. A total of 7 lines are available on plastic sepia, paper sepia, or blackline.

The 24-channel data are supplemented by single-channel sparker, 3.5- and 12-kHz precision-depth recordings on 35-mm microfilm, digital navigation, bathymetric, and magnetic data. The magnetic data were collected using a Proton Precession Magnetometer with the sensor towed 250 m astern at a depth of 10 m. The sampling rate was 3 sec digitized to 5 min and corrected to the IGRF-75 reference. Navigation was by satellite.


1. Common-Depth Point Seismic Data:

         24-fold multichannel seismic data for 7 lines, 7 sections available on plastic sepia, paper sepia, and blackline.

2. Single-channel Sparker Data

         1 Reel 35-mm Microfilm (No. 2123) with 3.5 kHz and 12.5 kHz precision-depth recordings.

3. Merged navigation, gravity and bathymetric data in MGD77 format on 1 magnetic tape, (9-track, 1600 bpi, ASCII). This is also available on CD-ROM.

4. 2 Shotpoint Location Maps available on plastic sepia, paper sepia and blackline.