Expert advisory government panels on the prevention of volcanic disasters have compiled a final report for revising volcanic activity observation methods and eruption warning systems in the wake of the explosion of Mt. Ontake last September on the prefectural border of Nagano and Gifu.
As part of the recommendations in the report submitted to the government on Thursday, the team of experts of the Central Disaster Prevention Council called for making the current five-level scale for volcanoes clearer, not in a uniform way, but for individual volcanoes.
The wide-ranging review recommends changing the current "warning level one," which describes the relevant state of volcanism as "normal," to "Be aware that this mountain is a volcano," the report said.
The government plans to adopt measures in line with the expert panel proposals from fiscal 2015, marking a major review of antidisaster countermeasures of volcanoes.
The final report was worked out in co-operation between the council panel and a study group of the Meteorological Agency's Coordinating Committee for Prediction of Volcanic Eruptions.
Regarding how to issue volcanic information to climbers, the report noted that lessons must be drawn from the fact that many people were killed or injured when hit directly by volcanic cinders in the eruption of Mt. Ontake.
A new prompt reporting arrangement must be created to inform people of an eruption through such means as an emergency warning via cellular phones, it said.
As for eruption risk warning levels, the report said the the warning level should be raised more promptly in a way well suited to rapid changes in volcanic activities.
A detailed list of eruption risks of individual volcanoes, which have so far been ambiguous and not open to the public, will be announced during fiscal 2015 after scrutiny of each volcano's degree of hazard, officials said.
The warning issued shortly before the eruption of Mt. Ontake on Sept. 27 said the mountain was in a state of "level one," or normal volcanism, which the report pointed out was likely to have misled the climbers to believe level one meant "safe and secure."
The report stressed the explanation of level one should be changed to an expression such as "Be aware that this is a volcanic mountain."
The final report also sought improvement of shelters on volcanic peaks and strengthening of observation systems.
The number of volcanoes under around-the-clock surveillance should be increased to 50 across the country, by adding three, including Mt. Hakkoda in Aomori Prefecture, according to the report.
New equipment should be installed for early detection of precursors of eruptions, such as devices for measuring changes in temperatures and components of gases at places close to craters, it said.
In addition, studies should be conducted on the advisability of fostering a younger generation of volcano research experts in co-operation with universities and other institutions, as well as reemployment of retired officials of the Meteorological Agency, the report said.
The government plans to revise the Active Volcanoes Countermeasures Law during the current Diet session with a view to making it obligatory for each municipality and observatory to set up a disaster prevention council for each volcano under around-the-clock surveillance.
The government will also set out a basic volcano hazard countermeasure policy based on the final report with the aim of making it serve as guidelines for local governments in crafting evacuation programs to prepare for volcanic eruptions.
Toshitsugu Fujii, professor emeritus of the University of Tokyo, who chaired the Disaster Prevention Council's expert panel, said, "The lesson from the eruption of Mt. Ontake is that the facts were brought to light that surveillance and evaluation arrangements at the time of the eruption which were currently available were insufficient," adding, "Taking all this into account, we worked out the report to clarify what is desirable for really effective preparations against volcano hazards."