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Whakaari/White Island is an active andesite stratovolcano, situated from the east coast of the North Island of New Zealand, in the Bay of Plenty. It is New Zealand's most active cone volcano, and has been built up by continuous volcanic activity over the past 150,000 years.〔(【引用サイトリンク】title=White Island )〕 The nearest mainland towns are Whakatane and Tauranga. White Island has been in a near continuous stage of smoking since it was discovered by James Cook in 1769. The island is roughly circular, about in diameter, and rises to a height of above sea level. However this is only the peak of a much larger submarine mountain, which rises up to above the nearby seafloor, making this volcanic structure the largest in New Zealand. Sulphur mining was attempted but was abandoned in 1914 after a lahar killed all 10 workers. The main activities on the island now are guided tours and scientific research. ==Volcanology== Whakaari's eruptions have produced both lava flows and explosive eruptions of ash. It is New Zealand's most well-known active marine volcano, attracting scientists and volcanologists worldwide as well as many tourists. It is part of the Taupo Volcanic Zone. Volcanologists from the (GeoNet Project ) continually monitor the volcano's activity via surveillance cameras. Survey pegs, magnetometers and seismograph equipment for early earthquake warnings via radio have also been installed on the crater walls. The island is usually on an alert level rating of 1 or 2 on a scale of 0 to 5. At most times the volcanic activity is limited to steaming fumaroles and boiling mud. In March 2000, three small vents appeared in the main crater and began belching ash which covered the island in fine grey powder. An eruption on 27 July 2000 blanketed the island with mud and scoria and a new crater appeared. Major eruptions in 1981–83 altered much of the island's landscape and decimated the extensive pōhutukawa forest. The large crater created at that time now contains a lake, whose level varies substantially. Between July and August 2012 White Island showed signs of increased activity with lake and gas levels rising from inside the crater. On 5 August 2012 a minor eruption occurred,〔(【引用サイトリンク】url=http://www.stuff.co.nz/science/7425606/Visitors-warned-off-erupting-volcano )〕 sending ash into the air. More eruptions have followed since. Continued volcanic activity and tremors on 25 January 2013 suggested another eruption was imminent. A small eruption occurred on 20 August 2013 at 10.23am, lasting for 10 minutes and producing mostly steam. According to ''The New Zealand Herald'' newspaper, "Civil Defence will monitor White Island (Whakari) following a small eruption which could be part of a sequence leading to a bigger event." 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「Whakaari/White Island」の詳細全文を読む スポンサード リンク
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