GAS HYDRATES IN THE SEA OF OKHOTSK OFF KAMCHATKA AND PARAMUSHIR ISLAND

Abstract

Between 1982 and 1984, teams from the Institute (of volcanology) investigated a hydroacoustic anomaly in the Sea of Okhotsk off Paramushir Island that appeared on sonar traces as a dark water plume. Later a combination of geological and geophysical methods, among them continuous seismic profiling (CSP) with a sparker source, whose emission was centered between 70 and 100 Hz was used. Analysis of the CSP data suggested that the anomaly was gaseous in origin and the water plumes consisted of water permeated by hydrocarbon gas derived from underlying deposits of gas hydrates which was later confirmed in 1986. In order to define the scale of occurrence of the gas hydrates, in 1986 a regional CSP survey was conducted in the Sea of Okhotsk off the Kamchatka Peninsula and Paramushir Island. The area encompassed the eastern part of the Lebed'ya (Swan) Bank and the northern part of Atlasov Trench, with interest in the possibility of finding gas hydrates. the volume of hydrocarbon gases preserved in the sediments under the sea bottom in this area may reach 2 trillion m3.