5:15 PM - 7:15 PM
[SVC31-P08] Experiment using an unmanned aerial vehicle (UAV) for an emergency survey of the eruption of Mt.Fuji
Keywords:UAV, Volcanic eruption, Volcano disaster, Emergency survey
After a volcanic eruption occurs, confirming the location of the crater and the distribution of lava flows is crucial for ensuring the swift evacuation of residents and implementing disaster prevention measures. When Mt. Fuji is erupting, the situation is monitored using CCTV cameras installed in the surrounding areas. However, the forest cover surrounding the base of Mt. Fuji makes it challenging to assess the situation, depending on the location of the eruption. In such cases, aerial surveys using manned helicopters or unmanned aerial vehicles (UAVs) are effective. Because of the significant elevation differences in volcanic regions, it is necessary to fly at high altitudes to obtain an overview of these areas. In addition, UAV operation can be difficult because of low temperatures, strong winds, and unstable weather conditions. Therefore, this study verified the flight capabilities of UAVs at high altitudes, the methods for capturing images, and the accuracy of the data obtained by conducting a demonstration at the fifth station of Mt. Fuji (at an elevation of approximately 2,300 m). The demonstration was conducted on November 14, 2024, and involved two different aircraft: the YAMAHA FAZER R G2 and DJI Mavic 3T. The weather during the experiment was sunny to cloudy, with ground temperatures ranging from 1 to 4 °C and average wind speeds of 6 to 10 m/s. FAZER R G2 is a gasoline-powered unmanned helicopter that can be operated remotely via LTE communication or satellite connection. Video footage was captured using both a flight control camera and a payload camera (GoPro) mounted on the underside of the aircraft. It flew at an altitude of 100 m above the ground along a contour line of approximately 2,400 m, covering approximately 5 km in 30 minutes. This confirmed that the drone could operate at low temperatures, high altitudes, and in strong winds. Considering the fuel consumption, the aircraft could fly for approximately 60 min, allowing for longer survey durations than those of typical electric UAVs. The Mavic 3T is an electric unmanned multicopter used for topographical surveys and infrastructure inspections. It is relatively small, weighing 920 g and measuring approximately 35 cm in length, and is equipped with both visible light and thermal cameras. Flights with Mavic 3T were conducted both at night and during the day, capturing videos and still images from high altitudes and targeting the summit area from an altitude of about 3,800 m above sea level. The drone flew to 2 km from the takeoff point and reached approximately an altitude of 1,500 m above the ground. Although UAV battery performance typically declines at low temperatures, Mavic 3T showed no significant performance drop, even at approximately 1–3 °C, and it successfully operated at average wind speeds of approximately 10 m/s. During night flights, the thermal imaging camera clearly distinguished the boundary between bare land and forested areas (Fig. 1 (a)), as well as the temperature differences in snow-covered regions (Fig. 1 (c)). Boulders larger than 5 m and steep cliffs (Fig. 1 (c), Fig. 2 A, B) were also identified at a distance of approximately 1.5 km. During daytime flights, when backlighting or shadows made it difficult to assess the situation using a visible camera, thermal camera images effectively confirmed the topography of slopes and valleys. The results of the demonstration confirmed the applicability of UAVs for surveys of volcanic eruptions. Unmanned helicopters can serve as alternatives to manned disaster-prevention helicopters when safety concerns hinder their use. The video images recorded by the FAZER R G2 can also be shared using a web conferencing system. Furthermore, aircraft with effective zoom capabilities, such as Mavic 3T, can assess the situation from a safe distance above the summit. Owing to the addition of thermal cameras, phenomena involving high temperatures and topographical changes, such as lava flows and newly formed craters, can be observed at night.