• Tuesday, September 18, 2018
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Is there any way to detect signs of abnormality in volcanic activity?

  • JAPANESE MINISTRY OF DEFENSE

    Soldiers with the Japan Self-Defense Forces and firefighters climbed Mt. Ontake for a rescue operation following the Sept. 28, 2014 eruption, near Otaki that claimed the lives of 58 people.

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Once again, indications of a coming eruption were not spotted.

On Jan. 23, Mt. Motoshirane erupted suddenly. Twelve people, including Ground Self-Defense Force members who were undergoing training and skiers at a resort near the crater, were killed or injured after being struck by volcanic rocks.

The agency did not issue an alert.

The eruption of Mt. Ontake in 2014 claimed the lives of 58 people after no warning was issued. The government has since improved volcano surveillance, but it is regrettable that the lessons from the Mt. Ontake eruption were ultimately not utilized.

The Japan Meteorological Agency must enhance the precision of its volcano surveillance to the greatest extent possible.

Mt. Kusatsushirane, a collective term for the volcanic mountain chain that includes Mt. Motoshirane, had been considered stable. On a five-level scale, its volcanic alert level was at the lowest level — Level 1.

There were no records of major eruptions on Mt. Motoshirane for 1,000 years or more, and the volcano was not a subject of surveillance.

Seismometers and surveillance cameras have been installed for Mt. Shirane, about 1-1/4 miles north of Mt. Motoshirane. The agency could not even confirm the eruption and failed to issue an eruption notice immediately. About two hours later, it raised the volcano’s alert level to Level 3, which restricts entry to the mountain.

The agency hastily decided to install seismometers and other equipment at the mountain. What are the factors that cause a series of eruptions to be unanticipated? A thorough analysis of this matter must be used to improve observation techniques.

The type of volcanic eruption that occurred is a factor in the failure to catch early warning signs.

Experts have pointed out the possibility of a phreatic eruption. In such an eruption, steam from magmatic heat spouts out along with volcanic ash and rocks. It is harder to spot than the type of eruption in which magma erupts directly.

Over the past 200 years, Mt. Kusatsushirane has primarily experienced phreatic eruptions. Is there any way to detect precursors? High hopes are placed in the wisdom of experts.

Volcanic tremors and other volcanic activity has continued in the area, although infrequently. Further eruptions cannot be ruled out. There is also the risk of avalanches and mud flows triggered by the activity.

The agency is urged to provide information accurately and swiftly. A review of the current disaster preparedness is urgent.

An eruption hazard map that projected damage from an eruption of Mt. Kusatsushirane failed to predict the current situation.

Also, of the five towns and villages that are part of the volcanic disaster alert area, only Tsumagoi has created evacuation plans.

The area is popular for hot springs, skiing and other attractions. Local governments are urged to become aware of the risk of active volcanoes and reinforce countermeasures to reduce future volcanic damage.

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