The Japan Meteorological Agency (JMA) reported that eruptive activity continued at Shinmoedake (Shinmoe peak, a stratovolcano of the Kirishimayama volcano group) during 11-18 August. The number of volcanic earthquakes located beneath Shinmoedake, first detected in late October 2024, continued to be frequent; volcanic tremor was also occasionally detected, notably during eruptive events. Sulfur dioxide emissions on 12 August were characterized as high, averaging 1,000 tons per day. Ash plumes were continuously emitted during 0100-1650 on 13 August rising as high as 500 m above the crater rim and drifting N and NW. At 1050 and 1422 on 15 August ash plumes rose 300 m above the crater rim into weather clouds. The Alert Level remained at 3 (on a 5-level scale) and the public was warned to exercise caution within 3 km from Shinmoedake 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)