Thermal infrared investigation of the pyroclastic flow deposits and dome region of Bezymianny volcano, Kamchatka, Russia

Bezymianny (Kamchatka, Russia) is an active stratovolcano that contains a summit lava dome and pyroclastic flow (PF) sheet to the southeast. Two recent eruptions (24 December 2006 and 11 May 2007) generated fresh pyroclastic flows on the southeastern flank. During the winter of 2006, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) collected several day- and night-time images to monitor the December eruption deposits and subsequent events. A field campaign in August 2007 was conducted to investigate recent changes at the lava dome and to map the new PF deposits. Within the cloud-free night time ASTER image from 30 June 2007, seven ASTER thermal infrared (TIR) 90 m pixels were identified as being thermally-anomalous and were investigated in the field. Both handheld Forward Looking Infrared Radiometer (FLIR) and thermocouple probe data were obtained and compared to the satellite TIR data. Helicopter- and ground-based FLIR surveys revealed thermally-elevated PF deposits that contained warm blocks and fumaroles. The maximum fumarole temperature within the December 2006 PF deposit was 377C at a distance of five kilometers from the lava dome. At the terminus of the 24 December 2006 PF, seven kilometers from the dome, the maximum temperature recorded was 228C. This suggests that eight months after the December 2006 eruption, the deposit was of a sufficient thickness in this area to retain heat. In addition, the thickness of the deposit probably increased as the slope angle decreased approximately 4 kilometers from dome, which may explain the high temperatures observed. We present spaceborne, airborne and ground-based thermal data in order to compare direct and remote thermal observations of ongoing activity and provide the first ground-based TIR data of actively cooling PF deposits at Bezymianny.