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Disaster drill conducted near Japan's Mount Fuji
By Elaine Lies
TOKYO, May 22 (Reuters) - Towns around the foot of Mount Fuji on Tuesday conducted their first disaster drill for a possible eruption after months of faint, but increasing, seismic activity under Japan's famed national symbol.
The number of small, imperceptible tremors beneath Fuji, which last erupted nearly three centuries ago, has risen sharply since last September, when 35 were recorded compared with only one or two a month in previous years.
"There are no signs of an eruption, but we decided to seize this opportunity because awareness that Fuji is an active volcano is high right now as a result of the tremors," said an official of the government in Shizuoka, one of two prefectures stradded by the 3,776-metre (12,390 ft) cone-shaped, snow-capped peak.
The drill involved testing communications between government offices and local residents, with some towns broadcasting mock warnings over loudspeakers.
Vulcanologists say the drills do not mean an eruption is expected any time soon, but the mountain's close proximity to Tokyo -- some 150 km (95 miles) west of the sprawling metropolis of 13 million people -- warrants careful watching.
Activity hit a peak of 221 tremors a month last November but then fell off early this year until April, when 132 tremors were recorded. The number has risen again in this month, with 138 already recorded by May 16. None was perceptible to humans.
Another drill is set to be carried out by neighbouring Yamanashi prefecture on June 3, the 10th anniversary of an eruption at southwestern Mount Unzen that killed 43 people.
Tuesday's drill also involved relaying to several government offices, as well as to nine cities and towns near the mountain, a mock message that a number of relatively shallow earthquakes -- often a precursor of an actual eruption -- had been detected.
"In the event of an actual eruption, transmitting information promptly is the most important thing. We wanted to make sure we could do this," the Shizuoka official said.
STILL ACTIVE, WARRANTS WATCHING
Yoshiaki Ida, a vulcanologist at prestigious Tokyo University, said an eruption is far from close.
"It's always difficult to predict with a volcano," he said. ";In Fuji's case, though, there still are no other signs, such as shallower earthquakes or changes in the mountain's shape that could signal the movement of magma.";
Mount Fuji, an inspiration for centuries for Japanese artists, last erupted in 1707 but is still considered active. A volcano can only be listed as dormant if it shows no signs of activity for 2,000 years.
Its increased activity has made it the focus of attention for vulcanologists for several months, and studies have been made of past eruptions to determine what could happen if it blows its top.
Plans have also been made to intensify monitoring by increasing the number of instruments used to detect seismic movements.
Japan sits atop the junction of three tectonic plates, the immense slabs of the earth's crust whose gradual movements are thought to cause earthquakes when they press against each other.
This makes it one of the world's most earthquake-prone countries, and it is regularly jolted by tremors of varying strength.
Last year, one of the most active in recent years, saw three volcanic eruptions, including one that forced the evacuation of an entire island south of Tokyo last September.
-- PHO (firstname.lastname@example.org), May 22, 2001