The Japan Meteorological Agency (JMA) reported that eruptive activity at Suwanosejima's Ontake Crater continued during 25 August-1 September. Incandescence was observed nightly in webcam images. Eruptive events during 25-31 August produced ash plumes that rose as high as 2.4 km above the crater rim and either rose straight up or drifted N. Ash-and-gas emissions were continuous from 2034 on 27 August to 0830 on 28 August, and again from 0911 on 28 August to 0500 on 29 August. Explosions at 1722 on 26 August and at 1047 on 1 September produced ash plumes that rose 1.5 km above the crater rim and 1.8 km above the crater rim and drifted N, respectively. Minor ashfall was reported in Toshima Village (3.5 km SSW). The Alert Level remained at 2 (the second level on a five-level scale) and the public was warned to be cautious within 1.5 km of 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)