JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 19-26 February. Crater incandescence was observed in webcam images nightly. Large blocks were sometimes ejected up to 400 m from the vent. Explosions were recorded at 0616 on 19 February, at 0604 and 2157 on 24 February, and at 1149 on 25 February; details of emissions were unknown. Eruptive events at 1702 and 2056 on 23 February produced ash plumes that rose at least 1 km above the crater rim and drifted S. Explosions at 2343 on 25 February and at 0431, 1402, 1910, and 1918 on 26 February produced ash plumes that rose 400-800 m above the crater rim and drifted S. The plume from the explosion at 1918 on 26 February rose to 800 m before entering into weather clouds. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.

Geological Summary. The 8-km-long island of Suwanosejima in the northern Ryukyu Islands consists of an andesitic stratovolcano with two active summit craters. The summit is truncated by a large breached crater extending to the sea on the E flank that was formed by edifice collapse. One of Japan's most frequently active volcanoes, it was in a state of intermittent Strombolian activity from Otake, the NE summit crater, between 1949 and 1996, after which periods of inactivity lengthened. The largest recorded eruption took place in 1813-14, when thick scoria deposits covered residential areas, and the SW crater produced two lava flows that reached the western coast. At the end of the eruption the summit of Otake collapsed, forming a large debris avalanche and creating an open collapse scarp extending to the eastern coast. The island remained uninhabited for about 70 years after the 1813-1814 eruption. Lava flows reached the eastern coast of the island in 1884. Only about 50 people live on the island.

Source: Japan Meteorological Agency (JMA)