SAPPORO – Hokkaido’s Mount Usu continued its seventh day of volcanic activity Thursday as tremors that began Wednesday night continued throughout the day and authorities again warned of the possibility of a violent eruption.
The tremors, which have a fairly high amplitude, are believed to have been caused by the movement of underground magma, Manabu Koyama, head of the Meteorological Agency’s Volcanological Division, told a news conference.
Hiromu Okada, a professor at Hokkaido University and head a team of experts monitoring Mount Usu, said they discovered a new crater several dozen meters in diameter in the morning and that the tremors may be caused by eruptions at the new crater.
The Coordinating Committee for the Prediction of Volcanic Eruptions said again on Wednesday that groups of newly formed fault lines on the 732-meter volcano could indicate a lava dome is being formed.
Meanwhile, the local antidisaster headquarters announced Thursday that it will build temporary housing units for people taking refuge in public facilities.
There are only 1,500 such units kept at public storehouses nationwide that are equipped with heating systems to suit Hokkaido’s cold weather.
It will take about a month, including at least two weeks for transportation, before the units can be installed, they added.
“We are not sure how long the evacuation will continue,” said the headquarters chief, Toshio Masuda. “But we made the decision by assuming the worst-case scenario.”