An interim report on a new evacuation plan assuming the eruption of Mt. Fuji has been completed, and it is estimated that more than 800,000 people in Shizuoka, Yamanashi, and Kanagawa live in areas targeted for evacuation due to volcanic stones and lava flows.
As a general rule, it is necessary to evacuate on foot in urban areas because serious traffic jams may occur if you move all at once by car.
The new evacuation plan has been reviewed by the Volcano Disaster Prevention Measures Council, which is made up of the three prefectures of Shizuoka, Yamanashi, and Kanagawa, the national government, and experts, following the revision of the hazard map assuming the eruption of Mt. Fuji last year. So, on the 30th, the interim report was presented.
According to this, the area where evacuation is required due to the eruption is divided into 6 stages, and it is estimated that the total number of people living in the target area is 805,600 in 27 municipalities in 3 prefectures of Shizuoka, Yamanashi and Kanagawa. ..
Of these, the number of people living in areas where pyroclastic flows, large volcanic stones, and lava flows reach within 3 hours is more than 116,000 in 10 municipalities in Shizuoka and Yamanashi, which is seven times the previous estimate. It is supposed to be.
People in these areas need to evacuate from dangerous areas immediately if the alert level is raised before a large-scale eruption due to the observation of volcanic earthquakes or crustal movements, or immediately after the eruption. I point out that.
In addition, when simulating the time it takes for residents to evacuate, it was found that in urban areas, if residents move all at once by car, serious traffic congestion may occur and evacuation may not be in time.
Although lava flows cause catastrophic damage, the flow speed is relatively slow in places with gentle slopes, so in urban areas where traffic congestion is expected, except for people with disabilities and the elderly who need to evacuate by car. In principle, a new policy of "evacuating on foot" was also shown.
"Wide area evacuation" is a step-by-step response to each volcanic phenomenon
The interim report also showed the concept of "wide area evacuation" to evacuate to the surrounding local governments when the effects of the eruption are widespread.
While large volcanic stones and pyroclastic flows required evacuation before they occurred, lava flows make it easier to understand the affected areas of damage if the location of the crater is identified. It will be gradually expanded according to the scale and situation.
In addition, there was a report on the concept of evacuation required for each season and region, such as how to deal with the "snow melting type lahar" where the accumulated snow melts and flows down due to the eruption.
The council will consider measures for people who need assistance in evacuation and measures for volcanic ash that may have a widespread impact, and will finalize an evacuation plan in 2022.
Lava flow tens of kilometers away
The basis of this evacuation plan is the "hazard map" released by the "Mt. Fuji Volcano Disaster Prevention Measures Council" in March last year.
Characteristic is a widespread lava flow.
It is estimated that the amount of lava that will flow out in the event of a large-scale eruption will reach 1.3 billion cubic meters, which is about twice the amount previously assumed. It is said that it will reach 7 cities and 5 towns in 3 prefectures, including Uenohara City and Sagamihara City in Yamanashi Prefecture, Odawara City in Kanagawa Prefecture on the southeast side, and Shimizu Ward in Shizuoka City on the south side, which are more than a kilometer away.
Pyroclastic flow
In addition, the "pyroclastic flow", in which high-temperature rocks, volcanic ash, and volcanic gas flow down the slope at high speed, flows down toward Fujiyoshida City and Fujinomiya City, Shizuoka Prefecture, and in some places. It was said that there is a risk of reaching farther from the crater because the amount of eruption has increased significantly compared to the conventional assumption.
It is estimated that the Higashifujigoko Road, which is an automobile-only road that is also being considered as an evacuation route, may be affected, which may affect the movement of people and logistics.
Snow melting type volcanic mudflow
It is estimated that the "snow-melting lahar", in which the accumulated snow melts in a pyroclastic flow and the water flows down while entraining earth and sand, extends up to 10 km or more through swamps and rivers.
Larger volcanic bombs larger than human head
For large volcanic bombs of about 20 cm to 30 cm or more that are blown by the eruption, it is said that they can reach up to 4 km from the crater assumed based on past cases.
The council states that all of these are areas affected by the eruption, and that a single eruption does not damage the entire area.
Up to 800,000 inhabitants in the evacuation area
The number of people living in the areas targeted for evacuation is 574,790 in Shizuoka Prefecture, 124,078 in Yamanashi Prefecture, and 106,759 in Kanagawa Prefecture.
Of these, in Kanagawa Prefecture,
32,854 in Minamiashigara, 21,789 in
Odawara,
16,753 in Kaisei, 14,345 in
Oi
, 8038 in Yamakita, and 7,674 in
Matsuda
.
There are 5306 people in Sagamihara City.
In Yamanashi Prefecture
▽ 45,348 people in Fujiyoshida City ▽ 25,288 people
in Fujikawaguchiko Town ▽ 22,476 people
in Tsuru City ▽ 15,309 people
in Otsuki City
▽ 7082 people in Uenohara City
▽ 3702 people in Nishikatsura Town
▽ 2694 people in Narusawa village ▽
1665 people in Yamanakako village ▽
506 people in Oshino village
▽ 8 people in Minobu town.
In addition, in Shizuoka Prefecture,
▽ 242,534 people in Fuji City ▽ 118,333 people
in Fujinomiya City ▽ 58,104 people
in Gotemba City ▽
45,334 people in Susono City ▽ 38,745 people
in Nagaizumi Town ▽ 3 people
in Numazu City 16,557 people ▽ 16,870 people
in Mishima City ▽
9742 people in Oyama Town
▽
6758 people in Shimizu Town
▽ 1813 people in Shimizu Ward, Shizuoka City.
“Evacuation is required before and after the eruption” 110,000 people 7 times more than before
This is a big change from the previous plans.
First, the number of people living in areas that require evacuation before or immediately after the eruption to protect themselves from lava flows and pyroclastic flows is estimated to be about 116,000 in Yamanashi and Shizuoka, which is about 1 so far. It has increased seven times as many as 16,000.
This is because the revised hazard map has expanded the range of possible impacts in areas such as Fujiyoshida City and Shizuoka Prefecture.
Among the volcanic phenomena associated with eruptions, it is difficult to escape after the occurrence of large volcanic stones and pyroclastic flows that exceed the size of a human head, and even relatively slow lava flows may be involved if it takes time to evacuate.
For this reason, this interim report assumes that people in areas where volcanic stones, pyroclastic flows, and lava flows are estimated to reach within 3 hours after the eruption will be evacuated in a short time.
Specifically, if the eruption alert level is raised in advance due to a volcanic earthquake or crustal movement before a large-scale eruption, or immediately after the eruption, evacuate from a dangerous area immediately. increase.
These targets are the following municipalities.
[Yamanashi Prefecture]
▽ Fujiyoshida City
▽ Oshino Village
▽ Yamanakako Village
▽ Narusawa Village
▽ Fuji Kawaguchiko Town
[Shizuoka Prefecture]
▽ Fujinomiya City (67,774 people)
▽ Fuji City (7907 people)
▽ Gotemba City (2795 people)
▽ Susono City (1993 people)
▽ Oyama Town (897 people)
The total number of residents in the 10 municipalities targeted is approximately 116,000, but it does not include tourists visiting the area around Mt. Fuji or those who commute to work or school in this area.
In addition, the cities, towns and villages that are subject to evacuation in stages depending on the time when the lava flow arrives are as follows.
[Yamanashi Prefecture]
▽ Tsuru City ▽ Otsuki City ▽ Uenohara City ▽ Kaisei Town ▽ Nishikatsura Town
[Shizuoka Prefecture]
▽ Shizuoka City Shimizu Ward ▽ Numazu City ▽ Mishima City ▽ Shimizu Town ▽ Nagaizumi Town
[Kanagawa Prefecture]
▽ Sagamihara City ▽ Odawara City ▽ Minamiashigara City ▽ Oimachi ▽ Matsuda Town ▽ Yamakita Town ▽ Kaisei Town
Evacuation of residents In principle, walk
Until now, we have widely called for evacuation by car, but since the lava flow is relatively slow, we have stated that we will evacuate residents on foot in principle.
Another factor is that the simulation revealed that serious traffic jams occurred in the city area and that there was a risk of escape delays.
By preventing traffic congestion, the aim is to give priority to evacuation by car for people who have difficulty moving on foot, such as the elderly and people with disabilities, which the new evacuation plan emphasizes.
Furthermore, until now, evacuation to a distant place was assumed, but in this interim report, since the area where the crater is likely to be affected after the eruption is known, it is not always safe to evacuate to a distant place. It is said that it can be secured.
It is desirable that the evacuation destinations for residents
should be gradually expanded to
1 first, a safe place for the municipality at that time,
2 a neighboring
municipality, and 3 a distant municipality .
Yamanashi Prefecture and others are planning to proceed with final studies on measures to deal with volcanic ash, which is feared to have a widespread impact, and the new evacuation plan is expected to be completed in early 2022.
Some local governments have an agreement to evacuate outside the town
Yamakita Town, Kanagawa Prefecture, where lava flows are expected to reach the center of the town, is taking measures such as concluding agreements with local governments in Saitama, Ibaraki, and Niigata so that residents can evacuate outside the town.
There are town halls and national roads in some areas on the south side where lava flows from the eruption of Mt. Fuji can reach, and about 8,000 people, about 80% of the townspeople, live in the town.
When lava flows arrive, it can be difficult to evacuate using national roads and continue operations at the town hall.
For this reason, the town aims to allow residents to evacuate outside the town, and from May to February last year, ▽ Miyoshi Town, Saitama Prefecture ▽ Sakai Town, Ibaraki Prefecture, and ▽ Murakami City, Niigata Prefecture. We have signed an agreement to cooperate.
The agreement stipulates that in the event of a disaster, they will accept evacuees and transport relief supplies to each other, and the town will consider specific evacuation methods based on the interim report released on the 30th. I am.
"Phenomenon that life can be fully protected by escaping accurately"
Mitsuhiro Yoshimoto, a senior researcher at the Mt. Fuji Research Institute in Yamanashi Prefecture, who was involved in the formulation of the interim report, said, "It is important for the general public to refrain from evacuating by car when it is time for people in need of assistance to evacuate to escape. Of course, I don't know if I want to escape by car, but I want people who need support to escape safely first and act accordingly. "
On top of that, Senior Researcher Yoshimoto said, "Until now, the training was based on evacuation by car, but in the future it is necessary to change the form, conduct evacuation drills on foot, and spread the idea of escaping on foot. The eruption itself cannot be stopped, but it is a phenomenon that life can be fully saved by escaping properly, and I want each person to have an opportunity to think about how to save their lives from the eruption. " ..
In addition, Professor Masato Koyama of Shizuoka University, who is the vice chairman of the review committee, said, "The revision of the hazard map has expanded the evacuation target area, and as a result of the simulation, it is not realistic to evacuate everyone by car because of traffic congestion. You may be worried, but the speed of the lava flow is as fast as people walk, so please keep calm. "
On top of that, "In reality, evacuation may be delayed due to various conditions. Look carefully at the hazard maps so far to see if you can evacuate, what if it takes time to evacuate, and how far you can actually walk to evacuate. It is important to try it. "
Furthermore, Professor Koyama said, "If you let the local government know about the evacuation issues that the residents felt, you can reflect them in the evacuation plan. How will your district evacuate in the wake of the interim report? I want the residents to think about it. "