An earthquake in 2011 has just been revealed as the cause of a 20-metre crack in the side of Mt. Fuji, but don’t panic, say local authorities.

Felt in Tokyo, we might have assumed that it was an aftershock of the March 11 quake off the coast of Tohoku; this tremor was actually a 6.4 magnitude earthquake centred in Shizuoka on March 15th 2011.

The crack (Image: KYODO)

The crack (Image: KYODO)

But, The Japan Times reports, an official from the local authority in Yamanashi prefecture has said that, “No abnormalities have been observed regarding Mount Fuji and the mountain shows no signs of an eruption.”

The official announcement seemed to confirm that the crack – which is several centimetres wide – was down to the quake and not, as could have been feared, caused by volcanic activity.

“Nothing has happened after more than a year (since the discovery of the crack) so Mt. Fuji is unlikely to erupt,” said Shigeo Aramaki, of the Yamanashi Institute of Environmental Sciences.

There was speculation in the aftermath of the March 2011 disaster that Fuji-san could erupt but this was often downplayed by officials. This latest announcement could be seen in some quarters as a relief, but there may be some doubts in the minds of worried citizens whose trust in officialdom has taken many severe blows since the earthquake and nuclear disaster.

Eagle-eyed hikers hoping to spot the crack may be disappointed, however, as it has since been covered over by pebbles and sand. Local experts are, they say, monitoring the situation.

The last time Fuji erupted was in 1707 and it has been classed as dormant since 1708. The area around the volcano has many hot springs, a certain amount of geothermal activity has been extremely good for tourism in Yamanashi and Shizuoka, the surrounding prefectures.