Temperature changes in the KUN-1 borehole, Kunashir Island, induced by the Tohoku Earthquake (March 11, 2011, M = 9.0)

The results of continuous (September 2010–September 2011) temperature monitoring in the 300-m-deep borehole on Kunashir Island are presented. There were several earthquakes, including the Tohoku one (March 3, 2012, M = 9.0), during the observation period, and they produced a significant coseismic response in the temperature field. The Tohoku earthquake was preceded by a constant decrease in temperature at the depth of 240 m with a mean rate of 0.02 K per month. The coseismic response was manifested in an abrupt (in à day) growth of temperature by 1.2 K. The relationships between the earthquake characteristics (magnitude, epicentral distance) and the amplitude of the coseismic temperature response in the borehole have been estimated. The deformation mechanism of the temperature response to earthquake preparation and implementation processes is suggested.