Authorities in Japan were keeping a close eye on Mount Asama, 140 km north--west of Tokyo, after the volcano showed increased activity overnight, Prime Minister Yoshiro Mori said on Wednesday morning.
The meteorological agency issued an emergency warning late last night after the number of volcanic earthquakes at the 2,568-metre mountain, soared from ten per day to about 40 per hour.
''We will be on alert, sufficiently monitor and continue to pay attention to it,'' Mori told reporters in Tokyo.
The quakes represented the highest level of seismic activity in two or three years at Mount Asama, which straddles the Gunma and Nagano prefectures.
The last small eruption took place on July 20, 1990. The last eruption to claim casualties was in 1947, when 11 climbers died. More than 1,000 people died in an eruption in 1783.
Bureau Report
