JMA reported that the number of volcanic earthquakes at Shinmoedake (Shinmoe peak, a stratovolcano of the Kirishimayama volcano group) began to increase on 18 December and remained elevated. A total of 300 earthquakes were located beneath the summit crater during 16-25 December. No changes were detected in deformation and emission data. The Alert Level was raised to 2 (on a scale of 1-5) on 25 December, and the public was warned to exercise caution within a 2-km radius of the crater.

Geological Summary. Kirishimayama is a large group of more than 20 Quaternary volcanoes located north of Kagoshima Bay. The late-Pleistocene to Holocene dominantly andesitic group consists of stratovolcanoes, pyroclastic cones, maars, and underlying shield volcanoes located over an area of 20 x 30 km. The larger stratovolcanoes are scattered throughout the field, with the centrally located Karakunidake being the highest. Onamiike and Miike, the two largest maars, are located SW of Karakunidake and at its far eastern end, respectively. Holocene eruptions have been concentrated along an E-W line of vents from Miike to Ohachi, and at Shinmoedake to the NE. Frequent small-to-moderate explosive eruptions have been recorded since the 8th century.

Source: Japan Meteorological Agency (JMA)