Borehole Seismic Data

ODP logging contractor: LDEO-BRG

Hole: 1247B

Leg: 204

Location: Hydrate Ridge - Cascadia Margin (NE Pacific)

Latitude: 44° 34.6589' N

Longitude: 125° 9.0766' W

Logging date: August 23-24, 2002

Bottom felt: 846 mbrf(used for depth shift to sea floor)

Total penetration: 220 mbsf

Total core recovered: 212 m (97.7 %)

TOOL USED: VSI (Versatile Seismic Imager) and QSST (Inline Checkshot Tool).

The logging data was recorded by Schlumberger in DLIS format. Check shots with the in-line check shot tool (QSST) were acquired at the base of the hole after the repeat run (DIT/APS/HLDT/HNGS/QSST/TAP). Zero-offset VSP stations were taken with the VSI at 5 m intervals between 129 and 220 mbsf. A walk-away VSP survey was attempted, but the VSI caliper arm broke down hole before any data could be acquired.

All processing, including first arrival picking and stacking, was performed by Schlumberger during Leg 204. The data was then converted into SEGY format at the Borehole Research Group of the Lamont-Doherty Earth Observatory, using the SEGY Save module in GeoFrame.

Stacks are generally calculated with at least seven good traces.

All the data in the SEGY files are sorted shot by shot (i.e. chronologically).

Gilles Guerin

Phone: 845-365-8671

Fax: 845-365-3182

E-mail: Gilles Guerin

Cristina Broglia

Phone: 845-365-8343

Fax: 845-365-3182

E-mail: Cristina Broglia