UPDATE 1-Cracks seen on Japan volcano, may signal eruption

By Kazunori Takada

  
TOKYO, March 30 (Reuters) - A military helicopter spotted cracks opening up 
on Thursday on the slopes of a rumbling volcano on Japan's northern island of 
Hokkaido, a sign the snow-capped mountain may be about to blow its top, 
officials said. 

Dozens of earthquakes and tremors were shaking the volcano and surrounding 
villages every hour and officials have told residents to move further away 
after nearly 10,000 people were evacuated on Wednesday amid warnings of an 
eruption. 

Cracks up to 100 metres (330 ft) long on the slopes of the 732-metre (2,402 
ft) Mount Usu were spotted by a military helicopter patrol, the 
Meteorological Agency said in an emergency bulletin. 

The Geographical Survey Institute had found the volcanic activity had 
stretched the area around the mountain by one cm (0.4 inches), the Kyodo news 
service said. 

Train services in the area had been disrupted, it said. 

Some 60 troops had been sent to snow-covered villages around Mount Usu to 
evacuate the elderly and disabled, said an official of the Ground Self 
Defence Force, Japan's army. 

More than 3,000 earthquakes and tremors, including five measuring close to 
five on the Japanese scale of seven, have shaken the area around the volcano 
since it started to rumble on Sunday, a Meteorological Agency spokesman said. 

``The volcanic activity at this time is greater when compared with previous 
pre-eruption activity,'' Naoya Mikami, deputy director of the Volcanological 
Division at the Meteorological Agency, told Reuters. 

However, he said he was unable to say whether such activity heralded a larger 
eruption than in 1978 when Mount Usu last blew its top, belching rocks and 
steam after a series of earthquakes. Mud slides triggered by the eruption 
killed three people. 

Local officials said they have extended the evacuation area and police 
patrolling towns near the foot of the volcano have been told to withdraw 
after ensuring all residents had left. 

Two quakes of magnitude 4.2 shook the area within minutes of each other late 
on Wednesday and officials said some tremors appeared to be growing more 
prolonged, perhaps signalling the movement of magma beneath the earth's 
surface. 

Officials warned of possible mud slides because the snow blanketing the 
slopes of the cone-shaped mountain could melt rapidly in the event of an 
eruption. 

Some 10,000 people were housed in schools and public halls after officials 
ordered residents of three nearby towns to move. 

``I was so scared, I couldn't sleep,'' Suki Matsuyama, a 73 year-old woman, 
was quoted by the Mainichi Shimbun as saying. 

``I didn't think earthquakes could be so frightening,'' she said. 

Some 3,300 military personnel are on standby, preparing food, water and 
blankets in case a full evacuation of the area becomes necessary and 40 
others were sent on reconnaissance missions, the Defence Force official said. 

A Hokkaido government official said 55,000 people living in five towns around 
the foot of the mountain, including the hot spring resort town of Toya, could 
be affected by an eruption. 

Scientists have said there is a strong chance of an eruption, since history 
shows the mountain's volcanic eruptions are often preceded by one to several 
days of heightened seismic activity. 

Mount Usu normally logs 20 to 30 tremors a month, the agency said. 

Officials have warned there is a chance that an eruption at Mount Usu could 
mimic the deadly flow of superheated gas and ash from Mount Fugen in southern 
Japan in 1991, which killed 43 people. 

00:22 03-30-00
__________________________________________________________

Public Seismic Network Mailing List (PSN-L)