Unpredictable Eruption Volcano Information Dilemma Oct 28 16:16
A red fire pillar that emerges in the dark. This is the eruption of Mt. Asama that occurred on the night of August 7. This eruption could not be predicted in advance. Fortunately, no one was sacrificed, but if this was daytime with many climbers ... The eruption alert level is the lowest “Level 1”. There was no information to alert the eruption in advance. It was an event that reminded me of the difficulty of prediction and the limitations of information disclosure.
(Social Department reporter Shinya Fujishima, Ikudai Kobayashi, Yuki Uchiyama)
Difficulties in information disclosure Lessons from the Mt. Ontake eruption
Volcano information announcement. It was the eruption of Mt. Ontake 5 years ago that faced the difficulty. The eruption alert level is the lowest “Level 1”. A sudden eruption with many climbers on Saturday in the autumn season. Although the scale of the eruption was small, there were 63 victims.
Was it possible to point out the possibility of an eruption in advance? In fact, before this eruption, the Japan Meteorological Agency has released information that shows changes in volcanic activity, such as an increase in earthquakes, three times. The information is “explanatory information” about the state of the volcano.
What is explanatory information?
In short, this “commentary information” is information that will be announced when a volcanic change occurs in the volcano.
However, the local government does not regulate mountain trails. Many climbers were involved in the eruption without their knowledge. Many people think that “why wasn't the information used?”
In fact, it conveys this information, the fact that there has been a change in volcanic activity, but the Japan Meteorological Agency does not say that it is a sign of an eruption.
Dilemma information
“Is the earthquake activity before the eruption shown in the explanation information a sign?” I (Fujishima) was at the press conference of the meteorological agency and volcano held at that time. I remember these questions.
However, the staff of the Japan Meteorological Agency and volcano explained. “When the earthquake occurred, we could not judge that it would erupt.”
It was possible to erupt if the level was raised, but the actual level was not reached, so the level could not be raised and only commentary was given.
In other words, it is information that has the dilemma that "I can't say anything definitive, but I can't afford to convey it."
“Extraordinary” information
On the other hand, in the study after the eruption, it was suggested that if there is a change in volcanic activity even if the level is not raised, information should be strongly transmitted. For this reason, it was decided that “Temporary” should be specified in the title of the information.
This “temporary” commentary. Operation began in the year following the eruption of Mt. Ontake (2015). By September 26, 268 times have been announced at 16 volcanoes nationwide. Still, the “ambiguity” that I had originally had no change. What does this mean?
“Regulate mountain trails” “Give up to approach the volcano”. In other words, the final decision was left to the local government that received the information or to climbers.
Still receiving difficult information
Because of the ambiguity of information, we interviewed the local government that suffered from the response. Mt. Aso in Kumamoto Prefecture.
When local information was announced in the surrounding local governments, the local government had a policy to restrict access to within 1 km from the crater. It is an advanced effort to regulate vague information at its own discretion.
However, there were concerns from the locals that forced the policy to change. If regulated, it could have an impact on “tourism”, a pillar of local industry.
As a result of discussions between the local government and the local community, it was decided to strengthen the monitoring system and consider whether to regulate it in the future.
“Although important information, there was no change in the eruption alert level, so it was difficult to get local understanding. There is still confusion about how to accept this information.”
On the other hand, there were local governments that implemented regulations. Tokachidake in Hokkaido. Last year, extraordinary commentary was announced when the eruption alert level was at the lowest level.
Kamifurano-cho, who was forced to respond, first posted on Tokachidake's activities on the town's homepage. In addition, leaflets were distributed to tourist facilities and convenience stores in the town to call attention to many people.
The mountain climbing course was also changed for the “mountain opening” that was approaching immediately before. The route was changed to a route that is more than 2 km away from the crater so that it would not be damaged in the event of an eruption. As with Mt. Aso, Tokachidake tourism is an industry pillar for the locals. It was a decision after distress.
“I want to do it as planned if possible. However, if there was a sudden eruption like Mt. Ontake, we couldn't deny the possibility of a catastrophe. I want to avoid the situation of quitting, and I was very worried about how to respond ... "
Handling temporary information
“If it is said that it is a sign of an eruption, it is difficult to respond drastically considering the impact on tourism and the economy with information that it is“ not sure ”.
NHK interviewed 47 local volcanoes around the country that the Japan Meteorological Agency has been continually monitoring to deal with temporary commentary information.
When asked about the national government's “whether a specific method is known”, it was found that about 23% of 11 volcanoes had “no known method” for climbers and residents. It was.
The most common reason is “under consideration”. Some say, “I do n’t know how to take it.” “I don't feel the need for information.”
Of the 36 volcanoes whose “well-known methods have been decided”, 14 volcanoes have no description in the “evacuation plan” that shows the disaster prevention measures of the local government, and it remains a question whether they can be operated continuously.
Expert “Local Government Support Measures”
How do experts see this situation? We asked Yasunori Tsuji, an associate professor at Yamanashi University, who is familiar with volcanic disaster prevention.
“Temporary information, like the eruption alert level, does not show a uniform disaster prevention response. It is very difficult for local governments to determine what to do on a case-by-case basis. The current situation is that the local government lacks specialized knowledge and know-how, which can lead to a heavy burden and lead to delays in response.
“Change” is a fact
To reiterate, “temporary commentary information” is “ambiguous information” that is announced without any grounds for raising the eruption alert level. The ambiguity of this information does not change immediately and may not change in the future.
The only thing that can be said is that this includes "facts" that indicate that "changes in volcanic activity" are occurring.
111 active volcanoes nationwide. “How can I protect my life?” In order not to repeat the Mt. In a situation where no one can say for sure, we have no choice but to make our own approach to the volcano.
If they were approaching the volcano, “temporary commentary” was announced. "What do you do?" I want you to start from where you think.
Social Department reporter Shinya Fujishima
Social reporter
Kobayashi Ikudai
Social Department reporter Yuki Uchiyama