Abstract
National Research Institute for Earth Science and Disaster Prevention (NIED) has conducted thermal observations of Unzendake Volcano using airborne MSS (VAM-90A) since Nov. 23 1990 through the period from initial stage to fierce eruptive activities of the volcano. The VAM-90A furnishes 8 spectral bands consist of 3 visible and near-infrared bands, 2 short-wave infrared bands and 3 thermal infrared bands to detect wide range of temperature from ordinary to highest at molten lava temperature for predicting volcanic eruption and watching eruptive activity.
Through three times observation of the crater temperatures from Nov. 23 1990 to March 24 1991, consecutive temperature rise could be detected which indicated a precursor of increasing eruptive activity of the volcano.
Thermal observation conducted on June 21 1991, when a lava dome was growing on the Jigokuato Crater and fierce pyroclastic flows had occurred frequently, could detect highest temperature of 475°C in a part of lava dome and high tempertures from 50°C to 243°C in the part of pyroclastic flow traces. Which are far high from the maximum temperatures ever observed by airborne MSS. It seems to be useful for precise recognition of the actual state of volcanic activity and estimating its perspective.
