FIRST it was an earthquake. Then it was a tsunami. Now Japan fears another nuclear disaster — this time because of a stirring volcano.

The Japan Times has reported a sleeping volcano next to its already damaged Sendai nuclear power facility has woken, and is beginning to shake.

The new activity comes barely a month after the sudden and unexpected eruption of Mount Ontake killed 57 hikers enjoying its until-then scenic slopes.

Volcanologists have warned that the enormous magnitude 9.0 earthquake of March 2011 may have increased the likelihood of volcanic activity throughout Japan — which sits on the “Ring of Fire” band of more than 100 volcanoes which forms the Pacific Rim.

Now the signs appear to be proving them right.

The waking of Mount Ioyama on the island of Kyushu comes after a recent warning from a prominent Japanese volcanologist about the Sendai nuclear plant’s vulnerability.

A cauldron eruption at one of several volcanoes surrounding the Sendai nuclear power plant could hit the reactors and cause a nationwide disaster, said Toshitsugu Fujii, head of a government-commissioned panel on volcanic eruption prediction.

Mount Ioyama sits virtually next door to the power plant. In recent weeks it has started experiencing tremors, the Japanese Metrological Agency’s volcano bureau says.

The implications for restarting the repaired Sendai nuclear power plant are serious.

The spectre of the ongoing crisis at the Fukushima nuclear power plant, which experienced a partial meltdown, continues to cause scandal and controversy.

A second such crisis would do irreparable damage to the industry.

Now Mount Ioyama has suddenly gone from the dormant end of the threat scale to the second-highest. This means the area around the crater can be regarded as dangerous, and that small-scale eruptions are likely.

Another volatile giant, Mount Sakurajima, sits some 40km from the Sendai facility. This is a very active volcano with frequent minor eruptions.