Acoustic Wipeouts Over the Continental Margins of Krishna, Godavari and Mahanadi River Basins, East Coast of India

Loss of seismic reflections, termed as acoustic wipeouts, are observed in the high resolution sparker seismic records over the continental shelf and slope of Krishna, Godavari and Mahanadi river mouths, east coast of India. The wipeouts observed in the sub-surface layers beneath the outer shelf off these basins (150 to 250 m water depth) result in a chaotic appearance, probably indicating the presence of gas mixed sediments, while those observed over the continental slope (beyond 500 m water depth) are mostly associated with faulted contacts and uplifts and represent an abrupt weakening of seismic energy or break in the pattern of surface and/or sub-surface reflectors. Though acoustic wipeouts result due to a variety of reasons, their association with vertical faults and location at depth off major river basins suggest that some of these might be due to migration of oil/gas along the faulted contacts from increased depths.