As police closed roads and tourists were told to stay away from a renowned volcanic steam vent on the slopes of Mount Hakone, local officials and businesses pledged Thursday to do what they could to prevent trade dying.
On Wednesday, the Meteorological Agency raised its alert for the area from 1, denoting normal, to 2, a level which regulates entry to areas around the volcanic vent. It warned of the risk of a small eruption, urging people to stay away from potentially dangerous areas.
An eruption of any size would likely have an impact on the Owakudani hot spring district.
“It is the destiny of Hakone to coexist with the volcano, while benefiting from it,” said Hakone Mayor Nobuo Yamaguchi, after meeting with the local association of hot spring hotel owners. “The alert was raised in a very limited area and we hope to provide accurate information to prevent groundless rumors from spreading.”
The number of volcanic earthquakes in the area reached 116 on Tuesday, the highest ever recorded in one day, the agency said.
The local town office issued an evacuation order for a 300-meter radius around Owakudani and closed the road leading to the area. It revised the evacuation area from the initially announced 700 meters.
The operator of Hakone Ropeway suspended a portion of its service running through Owakudani. Caution is advised over ash deposits and rocks that could rain down on the area if an eruption occurs.
Seismic activity has been increasing since April 26 in the Mount Hakone region, a popular spot for tourists and hikers in Kanagawa Prefecture, with tremors originating from areas around Owakudani.
On Tuesday, three minor earthquakes were reported in Hakone-Yumoto, while active steam bursts were also observed at hot spring facilities in Owakudani, leading authorities to believe volcanic activity is intensifying.
Meteorological Agency officials have become more concerned after the last of the three tremors was focused deeper than the earlier ones, raising the possibility of a steam eruption.
“The center of the earthquake that hit on Tuesday night was deep and the magnitude was large, which was clearly different from the ones before,” said Sadayuki Kitagawa, the agency’s head of volcano division. “It’s now in a different phase.”
A geological survey of Mount Hakone suggested there was an eruption between the end of the 12th century to the 13th century near Owakudani, but there has been no record of subsequent eruptions in the area. Volcanic activity in Hakone last increased notably in 2001, causing minor quakes and crustal deformation for about four months.
Although there has not been an eruption for centuries, that doesn’t mean underground magma has cooled, warns Takahiro Yamamoto, a volcano researcher at the National Institute of Advanced Industrial Science and Technology.
“(An eruption) in the Kamakura Period (1185-1333) is like it happened yesterday in terms of the life of a volcano,” Yamamoto said.