Japan's massive 2011 earthquake may trigger more, and larger, volcanic eruptions over the next few decades, perhaps even that of Mount Fuji — but predicting them remains close to impossible, a volcano expert said on Friday.

The nation last month suffered its worst volcanic disaster in nearly 90 years when Mount Ontake, its second-tallest active volcano at 3,067 meters (10,062 feet), suddenly erupted, raining down ash and stone on hikers crowding the summit.

The eruption killed 56 people, exceeding the deaths in the 1980 eruption of Mount St. Helens in the United States. Seven people remain missing, and recovery efforts have been suspended until the spring.