Sunday 7 February 2016

Eruption on Sakurajima volcano, Japan.

Sakurajima, an active volcano on Kyushu Island, Japan, underwent a spectacular eruption on Friday 5 February 2015, producing an ash column about 2.2 km in height as well as throwing incandescent material (glowing hot ash and/or rocks) several hundred meters from the crater. There are no reports of any damage or injuries following the event, but local authorities have placed a 2 km exclusion zone around the volcano as a precaution. 

An incandescent eruption on Sakurajima on 5 February 2016. ANP.

Sakurajima is one of Japan's most active volcano's with around 700 eruptions last year (the exact figure is hard to derive as eruptions often occur close together and may run into one another), though there have been no major events since September. This high level of activity is impressive, but prevents Sakurajima from becoming a major hazard, partly because people tend not to build homes or other structures too close to very active volcanoes, but also because the high levels of activity tend to prevent pressure within the volcano from building up to dangerous levels, which can lead to sudden very large and destructive eruptions on less obviously active volcanoes.

The location of the Sakurajima volcano. Google Maps.

Japan has a complex tectonic situation, with parts of the country on four different tectonic plates. Kyushu Island lies at the northeast end of the Ryukyu Island Arc, which sits on top of the boundary between the Eurasian and Philippine Plates. The Philippine Plate is being subducted beneath the Eurasian Plate, in the Ryukyo Trench, to the Southeast of the Islands. As it is drawn into the interior of the Earth, the tectonic plate is partially melted by the heat of the Earth's interior, and liquid magma rises up through the overlying Eurasian Plate to form the volcanos of the Ryukyu Islands and Kyushu.

 The movement of the Pacific and Philippine Plates beneath eastern Honshu. Laurent Jolivet/Institut des Sciences de la Terre d'OrlĂ©ans/Sciences de la Terre et de l'Environnement.

See also... and pyroclastic flow on Sakurajima, Kyushu.                                             The Sakurajima Volcano, situated on an island in Kagoshima Bay, Kyushu, underwent a large explosive eruption on the morning of Friday 4 October 2013, producing a 4 km high ash column and triggering... city covered in ash by eruption on Sakurajima Volcano.                                      An eruption on Sakurajima Volcano, situated on an island in Kagoshima Bay, Kyushu, has coated the city of Kagoshima in a layer of ash. The eruption... on Sakurajima.                              On 9 August 2013 the Japan Meteorological Agency reported a 50 minute eruption on Sakurajima Volcano, which is one of Japan's most active and sits on an island in Kagoshima Bay, Kyushu Island, which produced a 3.5 km high ash column, as well...
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