National Geophysical Data Center
MULTICHANNEL COMMON DEPTH POINT (CDP)
SEISMIC REFLECTION DATA
Additional Atlantic Survey Lines
Data Announcement 1980SE-BB
The National Geophysical Data Center is making available CDP
seismic reflection data for lines 18 through 38 from Atlantic
coastal areas. These data were collected as part of a program by
the U.S. Geological Survey (USGS) to survey the geological
framework of the United States coastal areas.
During 1978, USGS contracted with Geophysical Services, Inc.
(GSI), for GSI to collect 4,813 km of 48-channel seismic
reflection profiles along the continental margin between North
Carolina and Maine. Fifteen lines were acquired perpendicular to
the margin (lines 18 through 32) and six lines were acquired
parallel to the margin (lines 33 through 38). The data were
collected on the Motor Vessels CARINO and CECIL GREEN between May
and November 1978. Tuned airgun arrays totaling 2,000 and 1,400
in(cubed) of air were used by the respective vessels. A 3,600-m-
long hydrophone streamer was used by both ships.
The profiles were stacked by GSI and displayed in conventional
time-variant scaled format to 12 sec of recording time with
vertical scales of 2.5 in/sec and horizontal scales of 1.2 km/in.
Additional processing was applied to Line 25 across the Baltimore
Canyon Trough and Line 32 across Carolina Trough. Data collected
along line 25 over the Outer Shelf, Slope, and Upper Rise were
restacked with 1 1/2-km spaced velocity analyses, signature
deconvolution, deep-water multiple deconvolution, velocity
filtering (on shelf only), and time migration. The restacked
part and remaining parts of Line 25 were converted to depth
sections having a vertical scale of 1.2 km/in (vertical
exaggeration: 2/1). Data collected along two parts of line 32
were also restacked with signature and deep-water multiple
deconvolution. Line 32 was also converted to a depth section
except for the first 80 km near shore.
Lines 18-38 are available (per line) in blackline, paper sepia,
and plastic sepia. The data for these lines includes 92 charts,
4 reels of microfilm (1246-1249), and 1 OFR (#80-834).
The following documentation is provided with each line:
- location maps (sepia or blackline)
- velocity profiles (microfilm)
- shot-point listings (microfilm)
- copy of supportive USGS Open File Report
The shot-point locations are also available on magnetic tape.
Unless specified otherwise, tapes will be 9-track, 1600 bpi.
CDP data are also available on magnetic tape.
Please contact NGDC for prices.