One of the most active volcanoes in the world got a little more active today when the Showa Crater at Sakura-Jima blew a plume of ash 5,000 meters in to the sky on Sunday afternoon around 1600JST. This is the largest eruption at the Showa crater since observations started in 1955. The volcano also sent a pyroclastic flow down the side of the mountain nearly a kilometer. No casualties have been reported at this time, but the Japan Meteorological Agency is warning people who live in Kagoshimahosokyoku, to wear mask or apply a handkerchief while outdoors to avoid inhaling any ash. Visibility has also been reduced around Kagoshima bay. In the past year Sakura-Jima has erupted over 650 times making it one of the most active volcanoes in the world, and one of the most active near a large population. Westpacwx Author James Reynolds Documented Previous Eruptions at this very active Volcano in January of 2011. The video below is of that event. Note the Sonic booms that take place during the eruptions.
The largest recored eruption at the mountain in all craters occurred in 1914. The 1914 eruption was the most powerful in twentieth-century Japan. Lava flows filled the narrow strait between the island and the mainland, turning it into a peninsula. The volcano had been dormant for over a century until 1914. The 1914 eruption began on January 11. Almost all residents had left the island in the previous days, in response to several large earthquakes that warned them that an eruption was imminent. Initially, the eruption was very explosive, generating eruption columns and pyroclastic flows, but after a very large earthquake on January 13, 1914 which killed 35 people, it became effusive, generating a large lava flow.Lava flows are rare in Japan—the high silica content of the magmas there mean that explosive eruptions are far more common—but the lava flows at Sakurajima continued for months. The island grew, engulfing several smaller islands nearby, and eventually becoming connected to the mainland by a narrow isthmus. Parts of Kagoshima bay became significantly shallower, and tides were affected, becoming higher as a result. During the final stages of the eruption, the centre of the Aira Caldera sank by about 60 cm (24 in), due to subsidence caused by the emptying out of the underlying magma chamber. The fact that the subsidence occurred at the centre of the caldera rather than directly underneath Sakurajima showed that the volcano draws its magma from the same reservoir that fed the ancient caldera-forming eruption. The eruption partly inspired a 1914 movie, Wrath of the Gods, centering around a family curse that ostensibly causes the eruption. (Wiki)