Anomalous seismic reflections related to gas/gas hydrate occurrences alongthe western continental margin of India

Gas hydrates along continental margins are commonly inferred from the prese nce of bottom simulating reflectors (BSRs) on reflection seismic records. S hale and mud diapirs are often observed in the proximity of BSR-inferred ga s hydrates. Analysis of data from documented gas-hydrate occurrences sugges ts that the areas where mud volcanoes exist on the seafloor are promising l ocations for sediments with high gas-hydrate concentration. Along the weste rn continental margin of India (WCMI), we have identified several anomalous reflections on single-channel, analogue seismic records in the proximity o f BSRs, from which the presence of gas-charged sediments and gas seepages w as inferred. These features characterize both the shelf-slope region of the WCMI and the adjoining deep-sea areas. The seismic records also reveal mud /shale diapiric activity and pockmarks near the gas hydrates.