Studies on the lithosphere and the water transport by using the Japan Sea submarine cable (JASC): 1. Theoretical considerations

The Japan Sea Cable (JASC) was retired from telecommunications services and its ownership transferred to the scientific community in February, 1996. For the first stage of its scientific reuse program, a Japan-Russia joint project has been initiated to monitor electrical potential differences across the Japan Sea to study the electrical conductivity distribution in the Earth and the water transport across the cable. This paper describes preliminary investigations by forward modelling study to explore possible results from the voltage observation, before analyzing real data. On the resistivity structure, modelling has suggested that voltage data is most sensitive to the conductance of resistive lithosphere, especially at longer periods. Water transport modelling has shown that the heterogeneity of sub-bottom resistivity does not greatly influence the cable voltage, and that water transport of 5-6 Sv in the Japan Sea can generate voltage differences of 70-80 mV across the JASC. A preliminary observation was found to be roughly consistent with this estimation.