The Japan Meteorological Agency (JMA) reported eruptive activity at Me-Akan (also known as Meakan-dake, which means Meakan Peak) of the Akan volcanic complex during 16-23 September. Seismicity near Ponmachineshiri Crater that increased on 11 September continued to fluctuate at elevated levels. The seismic network recorded 27-50 daily volcanic earthquakes. Tilt in the direction of the crater continued at a low rate. Minor ashfall around the crater was visible on 16 September. During 17-23 September the volume of white steam-and-gas plumes rising from 96-1 Crater within Ponmachineshiri continued to be high; the plumes rose 200-800 m above the crater rim and drifting E and SE. The Alert Level remained at 2 (the second lowest level on a 5-level scale) and the public was warned to exercise caution within 500 m of Ponmachineshiri Crater.

Geological Summary. Akan is a 13 x 24 km caldera located immediately SW of Kussharo caldera in eastern Hokkaido. The elongated, irregular outline of the caldera rim reflects its incremental formation during major explosive eruptions from the early to mid-Pleistocene. There are four post-caldera stratovolcanoes, three at the SW end of the caldera and the other on the NE side. Conical Oakandake was frequently active during the Holocene. The 1-km-wide Nakamachineshiri crater of Meakandake was formed during a major pumice-and-scoria eruption about 13,500 years ago. The Meakandake group, composed of nine overlapping cones E of Lake Akan, has produced mild phreatic eruptions since the beginning of the 19th century. The main cone of Meakandake proper has a triple crater at its summit. Although recorded eruptions at Meakandake have consisted of minor phreatic explosions, four major magmatic eruptions with pyroclastic flows have also occurred during the Holocene.

Source: Japan Meteorological Agency (JMA)