In March of 2011 the massive, 9.0, Tohoku earthquake and resulting tsunami caused 3 of the 6 reactors of the Fukushima I Nuclear Power Plant to meltdown. Now as concerns are being raised about other nuclear plants in the country after an increase in volcanic activity.

Last month Japan’s Mount Ontake erupted, causing Japan’s worst volcanic disaster in 90 years. The eruption killed 56 and seven others remain missing.

Historically Japan has more volcanic activity than it has seen in recent years. Mount Fuji, for example, hasn’t erupted since 1707. Prior to that, however, it would erupt roughly every 30 years. It  is not unusual for large earthquakes to trigger rounds of volcanic activity and that may be what is currently taking place in Japan.

“The 2011 quake convulsed all of underground Japan quite sharply, and due to that influence Japan’s volcanoes may also become much more active. 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,” said Toshitsugu Fujii, a volcanologist and professor emeritus at the University of Tokyo to Rueters.

Fujii is raising concerns about the safety of some nuclear facilities in the wake of comments by Japanese regulators. Last month officials said that the two Sendai nuclear reactors were functioning within the safety regulations created after the Fukushima disaster.

Japan has been preparing to restart its nuclear energy program, a move that has met with considerable protest within the country after the Fukushima disaster. The two Sendai reactors, which are the first to be restarted, are close to several volcanos.

Officials planned to restart Sendai based on the assumption that there would be no eruption from these volcanos within the next 30 years. That assumption, however, may no longer hold.