翻訳と辞書 Words near each other ・ Lavanda ・ Lavanda, Crimea ・ Lavandeira ・ Lavandeira, Tocantins ・ Lavandevil ・ Lavandevil District ・ Lavandevil Rural District ・ Lavandin (horse) ・ Lava River Cave (Arizona) ・ Lava rock mountain snail ・ Lava shearwater ・ Lava spine ・ Lava stringer ・ Lava Tongue Pass ・ Lava Tree State Monument ・ Lava tube ・ Lava, California ・ Lava, West Bengal ・ Lava-lava ・ Lava-Ströme ・ Lava-Tudo River ・ Lavaa ・ Lavabit ・ Lavabo ・ Lavabon ・ Lavaca ・ Lavaca Bay ・ Lavaca County, Texas ・ Lavaca Flats Beds ・ Lavaca High School Dictionary Lists mini英和辞書 mini和英辞書 Webster 1913 Latin-English FOLDOC Wikipedia English ウィキペディア

翻訳と辞書　辞書検索 [ 開発暫定版 ] スポンサード リンク Lava tube ： ウィキペディア英語版 Lava tube A lava tube is a natural conduit formed by flowing lava which moves beneath the hardened surface of a lava flow. Tubes can be actively draining lava from a volcano during an eruption, or can be extinct, meaning the lava flow has ceased and the rock has cooled and left a long, cave-like channel. ==Formation== Lava tubes are a type of lava cave formed when an active low-viscosity lava flow develops a continuous and hard crust, which thickens and forms a roof above the still-flowing lava stream. Tubes form in one of two ways: by the crusting over of lava channels, and from pāhoehoe flows where the lava is moving under the surface. Lava usually leaves the point of eruption in channels. These channels tend to stay very hot as their surroundings cool. This means they slowly develop walls around them as the surrounding lava cools and/or as the channel melts its way deeper. These channels can get deep enough to crust over, forming an insulating tube that keeps the lava molten and serves as a conduit for the flowing lava. These types of lava tubes tend to be closer to the lava eruption point. Further away from the eruption point, lava can flow in an unchanneled, fanlike manner as it leaves its source, which is usually another lava tube leading back to the eruption point. Called pāhoehoe flows, these areas of surface-moving lava cool, forming either a smooth or rough, ropy surface. The lava continues to flow this way until it begins to block its source. At this point, the subsurface lava is still hot enough to break out at a point, and from this point the lava begins as a new "source". Lava flows from the previous source to this breakout point as the surrounding lava of the pāhoehoe flow cools. This forms an underground channel that becomes a lava tube.〔(The Virtual Lava Tube ) Large educational site on lava tube features and how they form, with many photos〕 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「Lava tube」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.