National Geophysical Data Center
MULTICHANNEL COMMON DEPTH POINT (CDP)
SEISMIC REFLECTION DATA
LINES IPOD, A & B - CAPE HATTERAS TO THE MID-ATLANTIC RIDGE
Data Announcement 1978-Q
The U.S. Geological Survey (USGS) and the National Science
Foundation (NSF) have recently made a CDP data set available to
the National Geophysical Data Center for public dissemination.
These data were collected for USGS/NSF in 1974 by Digicon, Inc.,
on the M/V GULF SEAL, as part of the International Program of
Ocean Drilling (IPOD). The field and processing efforts were
under the direction of the IPOD Site Survey Management Office at
Lamont-Doherty Geological Observatory and the USGS (Woods Hole,
Mass.). Portions of these data were processed in 1975 by the
Geophysical Services, Inc.; these portions contain approximately
1,825 km of data from Cape Hatteras heading southeast across the
The data are available in numerous formats including: (A) sepia
and blackline reproduction packages, (B) microfilmed records, and
(C, D) computerized data on magnetic tape.
A. SEPIA AND BLACKLINE REPRODUCTION PACKAGES
These data packages include CDP sections processed as follows:
COVERAGE BY SHOT POINTS
PROCESSING TECHNIQUE IPOD LINE A LINE B
(1) Scaled section 101-12,000 83-263 83-700
(2) True amplitude section 101-1,023 83-263 83-700
(3) Depth section 101-12,000 83-263 83-700
(4) Migrated depth section 700-1,200
(5) Migrated time section 1,539-2,160*
* Available only for full-scale sets.
The data are offered as a complete set or as separate
I. Continental Shelf, Slope, and Upper Rise - containing
Line A, Line B, and IPOD shot points 101-3,277.
II. Lower Continental Rise to Bermuda Rise - containing IPOD
III. Mid-Atlantic Ridge - containing IPOD shot points
21,230-22,690; 27,910-28,910; and 32,200-34,110.
The information below is available in sepia or blackline in half
scale* or full scale*.
Part I: Continental Shelf - Upper Rise
Part II: Lower Continental Rise-Bermuda Rise
Part III: Mid-Atlantic Ridge
*See notes below:
Full Scale Half Scale
True amplitude and scaled sections 2.5 in./sec 1.25 in./sec
24 tr./in. 48 tr./in.
Depth sections 1.66 in./km 0.83/in /km
1.21 km/in. 2.42 km/in.
24 tr./in. 48 tr./in.
Included with these packages are:
- Track charts of shot-point data (1:500,000);
- Navigation listing (microfiche) - note: Navigation
also available on magnetic tape;
- Velocity profiles (on microfilm).
B. MICROFILM COPIES
The CDP sections, track charts, and velocity profiles are
available on microfilm. (Includes 1 reel of CDP sections/maps
and 1 reel of velocity profiles).
C. SHOT POINT/NAVIGATION TAPES
The shot point/navigation data are available on magnetic tape and
Please specify 7- or 9-track, tape density and blocking factor
(5,120 characters or less; unblocked tapes are also available).
D. CDP TAPES
The data are available in a computerized format. Prices vary
depending on the number of tapes ordered.
Please contact NGDC for prices and for more detailed information on line
location or ordering information.