Oct 17, 2014 02:53 PM EDT By Russell Westerholm, UniversityHerald Reporter

A massive earthquake that hit Japan in 2011 may still make its effects felt years afterward, as a new study suggests the country's volcanoes are at a higher risk of erupting.

According to Reuters, Japan may experience more unexpected eruptions like one last month over the next few decades. The recent eruption came from Mount Ontake and the blast killed 56 people while seven still remain missing.

Japanese researchers said future volcanic eruptions will be hard to predict because the 2011 quake left them more active and volatile.

"The 2011 quake convulsed all of underground Japan quite sharply, and due to that influence Japan's volcanoes may also become much more active," Toshitsugu Fujii, a volcanologist and professor emeritus at the University of Tokyo, told reporters, 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."

Long overdue for an eruption is Mount Fuji, which last erupted in 1707, but had done so every 30 years or so.

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

9.0-magnitude quakes are known to make volcanoes more fragile, Fujii said, pointing to 50 years of research. He noted that such an issue has been especially problematic for Japan. The researchers have no reason to believe Mount Fuji will erupt any time soon, but as Fujii said, it will be near impossible to predict such an event. In Ontake's case, the volcano had a few tremors ahead of the eruption, but no tell tale signs of the blast that took palce.

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

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