17:15 〜 18:45
[STT34-P02] 伊豆大島におけるドローン繰り返し空中磁気測量
キーワード：空中磁気測量、ドローン、伊豆大島
We've conducted aeromagnetic survey in the caldera of Izu Oshima volcano by using a multirotor drone.
Izu Oshima is a basaltic active volcano, and multidisciplinary surveys and monitoring measurements are being performed. Grounded-based geomagnetic continuous observation shows that remagnetization process in caldera is ceasing. It may indicate that heat cooling since the last eruption in 1986 almost stops and preparation for the next event is starting.
In order to reveal the present condition of the shallow subsurface in the caldera, we obtained a wide and dense magnetic field data at the low altitude above the surface by aeromagnetic survey. The target area is 3 km by 3 km including the A crater and the B fissure of the 1986 eruption. Measurement height and line interval was almost kept at 50 m. Measurement of the geomagnetic field was done by using the optical pumping total intensity magnetometer.
As the result of modeling of the subsurface structure, lineation of magnetization appeared in the NW-SE direction, which is identical to the regional stress field. Especially, the region beneath the B fissure shows very low magnetization. It shows that the NW-SE line beneath the B fissure is structurally weak, and has potential to erupt in the future.
Also, preliminary data processing detected that the magnetization change of the model benath the A crater in negative and the B fissure in positive. It may indicates that the A crater is getting some heat supply while the B fissure is still cooling.
Izu Oshima is a basaltic active volcano, and multidisciplinary surveys and monitoring measurements are being performed. Grounded-based geomagnetic continuous observation shows that remagnetization process in caldera is ceasing. It may indicate that heat cooling since the last eruption in 1986 almost stops and preparation for the next event is starting.
In order to reveal the present condition of the shallow subsurface in the caldera, we obtained a wide and dense magnetic field data at the low altitude above the surface by aeromagnetic survey. The target area is 3 km by 3 km including the A crater and the B fissure of the 1986 eruption. Measurement height and line interval was almost kept at 50 m. Measurement of the geomagnetic field was done by using the optical pumping total intensity magnetometer.
As the result of modeling of the subsurface structure, lineation of magnetization appeared in the NW-SE direction, which is identical to the regional stress field. Especially, the region beneath the B fissure shows very low magnetization. It shows that the NW-SE line beneath the B fissure is structurally weak, and has potential to erupt in the future.
Also, preliminary data processing detected that the magnetization change of the model benath the A crater in negative and the B fissure in positive. It may indicates that the A crater is getting some heat supply while the B fissure is still cooling.