SISMIQUE REFLEXION EN EAU PROFONDE*

Reflection seismic profiles from the South‐East part of the Bay of Biscay are shown. They where shot in deep waters with continuation of some of the lines on the continental shelf.

Flexotir with one or two guns was used with 300% CD.P. Total charge weight per shot was 50 or 100 grams according to the number of guns. Ship speed was 6.5 knots and 1000 kilometers were recorded in 9 days. Trace intervals being 60 meters, good detail can be seen on the sections.

Good reflections were obtained in places where water was 4000 meters deep. Penetration is often 5 seconds (2 way‐time) below sea bottom.

Flexotir is a seismic method well suited for oceanographic surveys.