Thursday, 28 July 2022

Sakurajima volcano erupts in Japan, dozens ordered to evacuate after eruption

WION shows Japan's Sakurajima volcano, located on the island of Kyushu, erupted on Sunday, prompting evacuations in the region.

Sakurajima (Japanese: 桜島, literally "Cherry Blossom Island") is a so-called active stratovolcano, formerly an island and now a peninsula, in Kagoshima Prefecture in Kyushu, Japan. The lava flows of the 1914 eruption connected it with the Ōsumi Peninsula. It is certainly the most active volcano in Japan.

As of April 2021, the volcanic activity still continues, dropping volcanic ash on the surroundings. Earlier eruptions built the white sand highlands in the region. On September 13, 2016, a team of experts from Bristol University and the Sakurajima Volcano Research Centre in Japan suggested that the volcano could have a major eruption within 30 years; since then two eruptions have occurred.

Sakurajima is a stratovolcano. Its summit has three peaks, Kita-dake (northern peak), Naka-dake (central peak) and Minami-dake (southern peak) which is active now.

Kita-dake is Sakurajima's highest peak, rising to 1,117 m (3,665 ft) above sea level. The mountain is in a part of Kagoshima Bay known as Kinkō-wan. The former island is part of the city of Kagoshima. The surface of this volcanic peninsula is about 77 km2 (30 sq mi).

The geological history of the fascinating volcano is interesting.

There is a map of Sakurajima from 1902 that shows it as a distinct island.

Sakurajima is in the 25 km (15 mi)-wide Aira caldera, which formed in an enormous "blow-out-and-cave-in" eruption around 22,000 years ago. Several hundred cubic kilometres of ash and pumice were ejected, causing the magma chamber underneath the erupting vents to collapse. The resulting caldera is over 20 km (12 mi) across. Tephra fell as far as 1,000 km (620 mi) from the volcano. Sakurajima is a modern active vent of the same Aira caldera volcano.

Sakurajima was formed by later activity within the caldera, beginning about 13,000 years ago. It is about 8 km (5 mi) south of the centre of the caldera. Its first eruption in recorded history was in 963 AD. Most of its eruptions are strombolian, affecting only the summit areas, but larger plinian eruptions have occurred in 1471-1476, 1779-1782 and 1914.

Volcanic activity at Kita-dake ended around 4,900 years ago: later eruptions have been centered on Minami-dake. Since 2006, activity has centred on Showa crater, to the east of the summit of Minami-dake.

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