Preliminary Study on Magnetic Structure and Geothermal Activity of Tyatya Volcano, Southwestern Kuril Islands

We carried out reconnaissance surveys of the magnetic and geothermal fields on Tyatya volcano, Kunashiri Island, southwestern Kuril Islands. Two characteristic features were in the magnetic anomalies: topography dependent ones and locally scattered ones of which origin was unknown. Modeling of the topography dependent anomalies indicates that the Tyatya edifice is uniformly magnetized with magnetization of 7 A/m and any significant anomalies, that suggest the existence of thermally demagnetized parts, are not found. The result agrees with low heat discharge rate of 0.6 Mw from volcano surface. Judging from these ground-based data, it can be concluded that the volcanic activity of the shallower part of Tyatya volcano is very inactive at present.