Japan's massive 2011 earthquake could trigger more, and larger, volcanic eruptions over the next few decades, perhaps even that of Mount Fuji. Predicting them is close to impossible however, one volcano expert said Friday.

Last month, the nation went through 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, sending down ash and stone on hikers crowding the summit.

The eruption killed 56 people, easily exceeding the deaths in the 1980 eruption of Mount St Helens in the United States, according to Reuters. Seven victims are still missing, and recovery efforts have been suspended until the spring.

Japan could be moving into a period of increased volcanic activity touch off by the 9.0 magnitude earthquake of March 11, 2011, said Toshitsugu Fujii, a volcanologist and professor emeritus at the University of Tokyo.

"The 2011 quake convulsed all of underground Japan quite sharply, and due to that influence Japan's volcanoes may also become much more active," Fujii said, according to Reuters.

"It has been much too quiet here over the last century, so we can reasonably expect that there will be a number of large eruptions in the near future."

Earthquakes around the globe of magnitude 9.0 or greater have led to repeated volcanic eruptions in the last 50 years, sometimes within days, Fujii said.

Previous periods of seismic activity in Japan have seen major earthquakes interspersed with eruptions, he added.

One candidate for eruption is Mount Fuji, which used to erupt every 30 years, but has been silent since 1707.

"The last eruption was 300 years ago, ten times longer than before," Fujii said. "So it could erupt at any time."

Japan watches 47 of its 110 active volcanoes around the clock, but the research budget has always been less than for earthquakes. Critics say there is insufficient equipment as well, according to Reuters.

Predicting an eruption is hard even with the best measurement. Of Japan's nine major eruptions since 1977, the longest warning was a week before hand. Most are just hours before.

"Fuji is showing absolutely no signs of eruption at this point," Fujii said. "But that says nothing about next year."

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