Thursday, July 28, 2022

Sakurajima volcano erupts in Japan, dozens ordered to evacuate after eruption 日本で桜島火山が噴火し、噴火後に数十人が避難を命じられた

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.

Japanese language:


桜島(日本語:桜島、文字通り「桜島」)は、九州の鹿児島県にある、以前は島で現在は半島である、いわゆる活発な成層火山です。 1914年の噴火の溶岩流は、大隅半島とつながっていました。確かに日本で最も活火山です。

2021年4月現在も火山活動は続いており、周囲に火山灰が降り注いでいます。初期の噴火により、この地域に白い砂浜の高地が建設されました。 2016年9月13日、ブリストル大学と日本の桜島火山研究センターの専門家チームは、火山が30年以内に大噴火する可能性があることを示唆しました。それ以来、2回の噴火が発生しました。


北岳は桜島の最高峰で、海抜1,117 m(3,665フィート)に達します。山は金光湾として知られる鹿児島湾の一部にあります。かつての島は鹿児島市の一部です。この火山半島の表面は約77km2(30平方マイル)です。



桜島は幅25km(15マイル)の姶良カルデラにあり、約22、000年前に巨大な「噴火と洞窟」の噴火で形成されました。数百立方キロメートルの灰と軽石が放出され、噴火口の下のマグマ溜りが崩壊しました。結果として得られるカルデラは、直径20 km(12マイル)を超えています。テフラは火山から1,000km(620マイル)まで落下しました。桜島は、同じ姶良カルデラ火山の現代的な活火山です。


北岳の火山活動は約4,900年前に終わり、その後の噴火は南岳を中心に行われました。 2006年以降、南岳山頂の東にある昭和火口を中心に活動を行っています。

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