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Mount Yasur is an active volcano on Tanna Island, Vanuatu, high above sea level, on the coast near Sulphur Bay, southeast of the taller Mount Tukosmera, which was active in the Pleistocene. It has a largely unvegetated pyroclastic cone with a nearly circular summit crater 400 m in diameter.〔 It is a stratovolcano, caused by the eastward-moving Indo-Australian Plate being subducted under the westward-moving Pacific Plate. It has been erupting nearly continuously for over 800 years, although it can usually be approached safely. Its eruptions, which often occur several times an hour, are classified as Strombolian or Vulcanian. The glow of the volcano was apparently what attracted Captain James Cook on the first European journey to the island in 1774. Today the mountain is a sacred area for the John Frum cargo cult. Members of the cult revere John Frum, a deified messenger who foretold the bringing of wealth to the island by American forces, and believe he resides in Mount Yasur with his countrymen. The village of Sulphur Bay, the center of the movement, claims the volcano as part of their territory. A visiting television team〔''Kate Humble: Into the Volcano'', BBCTV2, 8 to 9 pm, 4 January 2015〕 found in a deep gully left by a lake which had suddenly drained, an exposure of old ash deposits including thick layers telling of two massive eruptions "more powerful than Mount St. Helens" several centuries or more ago; one of them had made the old caldera that Mount Yasur is inside. __NOTOC__ == Access restrictions == Mount Yasur is an easily accessible active volcano, and is a major Vanuatu tourist attraction. The Vanuatu Government monitors the level of volcanic activity in the interests of the public, both tourists and locals alike. This monitoring is carried out by the Vanuatu Geo-Hazards Observatory.〔http://www.geohazards.gov.vu/〕 The importance of the volcano to Tanna's tourism industry has resulted in the local government creating levels to restrict people's access. These levels range from 0-4 as follows: * Level 0 - Low activity, access to the crater allowed * Level 1 - Normal activity, access to the crater allowed * Level 2 - Moderate to high activity, lava bombs may land beyond the crater rim, access to the crater is closed * Level 3 - Severe activity with loud explosions, lava bombs ejected up to hundreds of metres outside the crater and large plumes of smoke and ash, access to the summit zone is closed * Level 4 - Major eruption affecting large areas around the volcano and possibly other parts of Tanna and even neighbouring islands, all access closed. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Mount Yasur」の詳細全文を読む スポンサード リンク
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