| 翻訳と辞書 |
| fissure vent ： ウィキペディア英語版 |
fissure vent
A fissure vent, also known as a volcanic fissure or eruption fissure, is a linear volcanic vent through which lava erupts, usually without any explosive activity. The vent is often a few meters wide and may be many kilometers long. Fissure vents can cause large flood basalts which run first in lava channels and later in lava tubes. After some time the eruption builds up spatter resp. ash cones and may concentrate on one or some of them. Small fissure vents may not be easily discernible from the air, but the crater rows (see Laki) or the canyons (see Eldgjá) built up by some of them are.
The dikes that feed fissures reach the surface from depths of a few kilometers and connect them to deeper magma reservoirs, often under volcanic centers. Fissures are usually found in or along rifts and rift zones, such as Iceland and the East African Rift. Fissure vents are often part of the structure of shield volcanoes.〔See e.g. http://www.geology.sdsu.edu/how_volcanoes_work/index.html V. Camp, Dept. of Geologic Sciences, Univ. of San Diego: How volcanoes work. Eruption types. Fissure eruptions.〕
==Iceland==
In Iceland, volcanic vents, which can be long fissures, often open parallel to the rift zones where the Eurasian and the North American Plate lithospheric plates are diverging, a system which is part of the Mid-Atlantic Ridge.〔http://jardvis.hi.is/sites/jardvis.hi.is/files/Pdf_skjol/Jokull58_pdf/jokull58-einarsson.pdf P. Einarsson: Plate boundaries, rifts and transforms in Iceland. Jökull No.28, 2008〕 Renewed eruptions generally occur from new parallel fractures offset by a few hundred to thousands of metres from the earlier fissures. This distribution of vents and sometimes voluminous eruptions of fluid basaltic lava usually build up a thick lava plateau rather than a single volcanic edifice. But there are also the central volcanoes, composite volcanoes, often with calderas, which have been formed during thousands of years and eruptions with one or more magma reservoirs undeneath controlling their resp. fissure system.〔http://www.geo.mtu.edu/~raman/papers2/Thordarson%20and%20Hoskuldsson%202008%20Postglacial%20volcanism.pdf Th. Thordarson, etal.: Postglacial volcanism in Iceland. Jökull no. 58, 2008〕
The Laki fissures, part of the Grímsvötn volcanic system, produced one of the biggest effusive eruptions on earth in historical times, in the form of a flood basalt of 12–14 km³ of lava.〔http://earthice.hi.is/grimsvotn_volcano Institute of Earth Sciences, University of Iceland: Grímsvötn. Received 9/24, 2014.〕 During the Eldgjá eruption A.D. 934-40, another very big effusive fissure eruption in the volcanic system of Katla in South Iceland, ~18 km³ (4.7 mi³) of lava were released.〔http://earthice.hi.is/katla_volcano Institute of Earth Sciences, University of Iceland: Katla. Received 9/24, 2014.〕 In September 2014, a fissure eruption is ongoing on the site of the 18th century lava field Holuhraun. The eruption is part of an eruption series in the Bárðarbunga volcanic system.〔See: http://earthice.hi.is/bardarbunga_2014 Institute of Earth Sciences, University of Iceland: Bardarbunga 2014〕
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「fissure vent」の詳細全文を読む
スポンサード リンク
| 翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|