Japan’s Meteorological Agency warned on Friday that Ioyama volcano in southern Japan, located roughly 64 kms from the Sendai nuclear plant, had increased activity that could lead to a small-scale eruption. Mount Ioyama that lies in the volcanically active Kirishima mountain range had been shaken by small tremors, some lasting as long as seven minutes.

“There is an increase in activity that under certain circumstances could even lead to a small-scale eruption,” said an official of the mountain that is at the second lowest level on the volcanic scale that means that its crater is dangerous. The local government imposed a one-kilometer travel ban around the crater and urged climbers to get down from the mountain.

The warning comes just a month after Mt. Ontake erupted suddenly, killing 57 people in Japan’s worst volcanic disaster in nearly 90 years. Japan is home to 100 active volcanoes.