Volcanic activity under Mount Azuma in Fukushima Prefecture is increasing slightly, according to monitoring data released Tuesday by a local meteorological observatory.
The Fukushima Local Meteorological Observatory said the information, which was provided by the Coordinating Committee for the Prediction of Volcanic Eruptions, is the first independent volcanic monitoring data available on the 1,949-meter volcano.
According to the observatory, Mount Azuma experienced 51 small-magnitude volcanic earthquakes on May 21 and 22, with the 39 tremors on May 21 the most recorded in a single day since November 1998.
The observatory also said four low-frequency tremors focused near shallow areas of inland mountains were recorded intermittently in March, while 40 were recorded in April. By May 22, 33 had already been felt, it said.
The observatory said it hopes to increase its number of observation stations to allow further monitoring of the increasing seismic activity. Currently, it has just one monitoring site, located at Mount Azuma.