10:45 AM - 12:15 PM
[SVC31-P08] Thermal infrared observation using UAV at Izu Oshima Volcano 2
Keywords:UAV, Thermal Infrared observation, Izu-Oshima
The Izu-Oshima volcano has been reported to erupt every 36-38 years of 107 ton order by studies of eruption histories (Nakamura, 1964 and Endo et al., 1988), and more than 30 years have already passed since the last eruptive activity (1986-1990). The Japan Meteorological Agency (JMA) has been observing ground deformation for a long period of time, and has observed the expansion of the mountain, which suggests magma accumulation. However, just before the last eruption, the ground deformation was stagnant for several years (Watanabe, 1988), and some precursor phenomena related to heat and volcanic gases were detected (Kagiyama and tsuji, 1987, hirabayashi et al., 1988). For this reason, we have been working on airborne thermal infrared observations using UAVs in the "Research on Monitoring and Forecasting of Volcanic Activities" of the current five-year plan (FY2019-2023). In this presentation, we will report the results of our research conducted in FY2022 on Izu Oshima Island.
The UAVs and thermal camera used for the observations were DJI Matrice 300RTK and DJI Zenmuse XT2 and all UAV flight operations and photography were outsourced to a contractor.The area of the orthorectified mosaic image in FY2022 was about 1700 m2 including the summit crater of Mt. Mihara, and was observed in one night under the following conditions: ground resolution of about 50 cm/pixel, overlap/sidelap rate of 90%/85%. On a separate day, under the same observation conditions, observations were made over the outer rim of the mountain, where a small amount of thermal activity was observed, and in order to ensure the accuracy of the temperature data, the data were also observed from several altitudes above the ground using the heat balance monitoring equipment and the copper plate prepared at the time of the observation as known temperature points. In order to measure air temperature and humidity at the altitude at which the images were taken, the drone was equipped with a portable weather meter to conduct the observations.
In the previous fiscal years, an apparent position information (altitude) error occurred on some routes during the observation of the Orth mosaic target area, which was thought to be caused by radio wave disturbance. As a countermeasure, we made it mandatory to use the real time kinematic (RTK) function during observation flights in FY2022, and ensured data quality by checking the quality of Exif information each time when the drone battery was changed. The ground base station for RTK was installed at the takeoff/landing location, and the automatic navigation route was set so that the pilot could always see the drone in flight for a more robust observation design. Actual observations were conducted in early February 2023, and we are currently analyzing these data obtained. In the future, we will examine the effectiveness of the drone thermal observation, including the observation method, for evaluating volcanic activity by calculating the amount of heat radiation after carefully examining the correction method for the obtained temperature observation values.
The UAVs and thermal camera used for the observations were DJI Matrice 300RTK and DJI Zenmuse XT2 and all UAV flight operations and photography were outsourced to a contractor.The area of the orthorectified mosaic image in FY2022 was about 1700 m2 including the summit crater of Mt. Mihara, and was observed in one night under the following conditions: ground resolution of about 50 cm/pixel, overlap/sidelap rate of 90%/85%. On a separate day, under the same observation conditions, observations were made over the outer rim of the mountain, where a small amount of thermal activity was observed, and in order to ensure the accuracy of the temperature data, the data were also observed from several altitudes above the ground using the heat balance monitoring equipment and the copper plate prepared at the time of the observation as known temperature points. In order to measure air temperature and humidity at the altitude at which the images were taken, the drone was equipped with a portable weather meter to conduct the observations.
In the previous fiscal years, an apparent position information (altitude) error occurred on some routes during the observation of the Orth mosaic target area, which was thought to be caused by radio wave disturbance. As a countermeasure, we made it mandatory to use the real time kinematic (RTK) function during observation flights in FY2022, and ensured data quality by checking the quality of Exif information each time when the drone battery was changed. The ground base station for RTK was installed at the takeoff/landing location, and the automatic navigation route was set so that the pilot could always see the drone in flight for a more robust observation design. Actual observations were conducted in early February 2023, and we are currently analyzing these data obtained. In the future, we will examine the effectiveness of the drone thermal observation, including the observation method, for evaluating volcanic activity by calculating the amount of heat radiation after carefully examining the correction method for the obtained temperature observation values.