[S-VC27] Mitigation of volcanic disasters - basic and applied researches

[SVC27-03] Research contribution to volcanic disaster prevention at Mt. Fuji by combining local 5G, satellite communications, ATV, and UAV

*Tatsuji Nishizawa¹, Mitsuhiro Yoshimoto¹, Ryo Honda¹, Akihiro Nakao², Kenji Nakai², Hiroshi Takezawa², Keita Kaida², Rin Dohi², Ayane Suzuki², Ryuta Yajima² (1.Volcanic Disaster Research Center, Mount Fuji Research Institute, Yamanashi Prefectural Government, 2.School of Engineering, The University of Tokyo)

Keywords:Mt.Fuji, Volcanic Disaster Prevention, Local 5G, Satellite Communication, UAV

The number of climbers on Mt. Fuji in 2023 was exceed 220,000, returning to about the same number as before 2019. Most of the mountain trails fall under the First Evacuation Zone specified in the Mt. Fuji Volcano Evacuation Basic Plan revised in Martch 2023. According to the plan, the climbers will be instructed to dismount when ‘Interpretive information on the volcano’s status (temporary)’ has been issued. To achieve the goal of “zero evacuation delays” in countermeasures against volcanic disaster of the Mt. Fuji, it is essential to quickly provide evacuation information, but Mt. Fuji faces the issue of weak communications infrastructure. A stable communication environment is essential for the smooth evacuation of the climbers, who are targeted to begin evacuation at the earliest stage in the plan. The First Evacuation Zone also corresponds to the expected crater area specified in the Mt. Fuji Volcanic Hazard Map revised in March 2021. The expected crater area is wider than any other active volcanoes in Japan. The area also varies depending on the scale of the eruption, Mt. Fuji is one of the most difficult volcanoes for which disaster prevention measures, as the expected eruption style and scale, as well as the volcanic disasters, are diverse. In order to reduce the disaster with the eruption of Mt. Fuji, it is desirable to be able to detect precursor eruption phenomena and estimate the approximate location of the crater through geophysical observations, such as seismometer, gravimeter, and GNSS. Or, once an eruption begins, we must quickly locate the crater and monitor the eruption state in real time. However, there is currently no effective method.
In 2021, Yamanashi Prefecture signed a cooperation agreement with the University of Tokyo to promote disaster preparedness on Mt. Fuji. As part of effort, they aim to build a real-time information transmission system using local 5G (L5G), which can be rapidly deployed on Mt. Fuji. The system consists of L5G, satellite communications, and a portable power source, packaged in a small amphibious all-terrain vehicle (ATV) capable of running rough terrain. In case of an emergency on mountain trail, the self-propelled system can travel to the location where a stable communications environment is needed and activate a L5G base station. The base station is connected to a satellite communications system to enable access to the internet. L5G is flexible way for various entities, such as companies and municipalities that are not telecommunications operators, to build networks on a spot basis within their own buildings or premises in response to the individual needs of a region or industry. Starlink is a satellite internet constellation operated by private aerospace company SpaceX and consists of an antenna and Wi-Fi router. If communications with any of the more than 5,000 small satellites orbiting in low Earth orbit can be secured, the internet communications will be possible anywhere in the world.
In October 2023, we conducted a demonstration experiment of the transmission system at the 6th station of the Yoshida route, which is used by more than half of all climbers of Mt. Fuji, and at the 4th station of the Fuji Subaru Line. Both are located in Yamanashi Prefecture. Permission to operate the L5G station at experimental sites has been granted in advance. As a result, we succeeded in establishing a stable Internet connection with a communication speed of over 100Mbps, within the L5G area. In addition, as a demonstration using the network, we conducted a real-time transmission test of web conferencing and aerial footage taken by a drone. If this transmission system is put into practical use, it will be possible to quickly transmit evacuation information to the climbers, guides, and stuff of mountain huts in the event of an emergency. It will also be possible to transmit footage of the crater and eruption state taken by drones and other equipment to the local task force in real time. Securing a stable mutual communication environment connecting the site and disaster response headquarters is expected to greatly contribute to mitigating eruption disasters.