Abstract
The results of a three-dimensional seismic survey of the continental slope off Shimokita Peninsula, NE Japan, reveal the detailed features of typical slumps and related fluid-migration paths in Pliocene and Quaternary formations. Dewatering structures, which are strongly dependent on the development of imbricate structures within slump sediments, acted to drain excess fluid that accumulated upon the slip planes related to slumping. Damped and dimmed reflections in the dewatering structures and in the slumps indicate that the distribution of natural gas is strongly related to fluid circulation in and around the slump sediments. Slumping and dewatering structures are probably typical phenomena in such a continental slope of high methane flux.
