GEOTHERMAL AREAS AT A SEA BOTTOM: GEOPHYSICS

Abstract

Sea bottom areas with evaluated heat flow are lo-cated mostly in tectonically active regions as well as continental geothermal areas. For example, the Sea of Japan, a marginal sea of the most tectonically ac-tive Pacific segment, is characterized by a rather evaluated heat flow (up to 4 HFU, Honshu) and may be regarded, from the point of view of the litho-sphere energetic balance, as a powerful geothermal area. First of all, the geophysical conditions of this sedimentary basin, namely elasto-hydro-thermo-electromagnetic (E-H-T-EM) field interaction, are of interest for prognosis and technology. We formulate a mathematical model and calculate the E-H-T-EM geophysical field interaction and signal propagation, caused by a seismic excitation in the geological structures of the basin of the Sea of Japan. The EM and T-signals near the surface of the sea bottom and the EM-signals at the water surface and in atmos-phere can be used for the monitoring of the dynamic processes beneath the sea bottom geothermal areas, similarly to the continental ones.