气象专家：火山喷发无法轻易预测

It has been three days since Mount Ontake, 200 kilometers west of Tokyo erupted, trapping dozens of climbers and covering the area with thick ash.

Rescue efforts have resumed, after a previous search was called off due to toxic volcanic gases. Authorities have confirmed the deaths of four of the 31 people who were found unconscious near the peak of Mount Ontake. 45 people are still missing. Meteorology experts say there had been a rising number of small earthquakes detected in the days leading up to the eruption, but still, the eruption could not have been prediction easily.

Mount Ontake is a popular hiking destination. About 250 people were thought to have been there during the eruption, mostly attracted by autumn foliage.

The peak last erupted in 1979, but no one died. Volcanoes erupt periodically in Japan, but there have been no fatalities since 1991.