盾形火山是一座大火山,直径通常为数英里,侧面坡度较小。熔岩 – 火山喷发期间喷出的熔岩或液体岩石 – 在盾构火山喷发时大部分是玄武岩,其粘度非常低(流动性很差)。因此,熔岩很容易流动并扩散到大面积区域。盾火山喷发通常涉及熔岩长距离传播并分散成薄片。因此,随着时间的推移,由于熔岩的反复流动而形成的火山山脉具有宽阔平缓的轮廓,远离山顶上被称为火山口的碗形凹陷。盾形火山的高度通常是它们的20倍,并且当从上方观察时,它们的名字与它们与古代战士的圆形盾牌相似。在夏威夷群岛发现了一些最着名的盾状火山。这些岛屿本身是由火山活动创造的,目前有两座活跃的盾状火山 – 位于夏威夷岛上的基拉韦厄火山和莫纳罗亚火山。基拉韦厄火山定期爆发,而莫纳罗亚(如上图所示)是地球上最大的活火山。它最后一次爆发于1984年。盾牌火山通常与夏威夷有关,但它们也可以在冰岛和加拉巴哥群岛这样的地方找到。虽然在盾火山中发现的火山爆发类型可能会有所不同,但大多数火山喷发都会爆发。火山爆发是最平静的火山爆发类型,其特点是玄武岩熔岩的稳定生产和流动,最终形成盾状火山的形状。火山喷发可能发生在山顶的火山口,也可能来自裂谷区 – 从山顶向外辐射的裂缝和通风口。据认为,这些裂谷带喷发有助于使夏威夷盾形火山的形状比其他盾形火山更加细长,这些火山往往更加对称。在基拉韦厄火山的情况下,东部和西南裂谷地区的火山爆发多于顶峰,因此形成了从山顶向东延伸约125公里,向西南延伸35公里的熔岩山脊。因为来自盾状火山的熔岩很薄而且流动,熔岩水蒸气中的气体如蒸汽,二氧化碳和二氧化硫是最常见的 – 在火山喷发期间很容易逃逸。因此,盾构火山不太可能发生爆炸性喷发,这种爆发在复合和火山锥火山中更为常见。同样,盾状火山通常比其他火山类型产生更少的火山碎屑物质。火山碎屑物质是岩石,灰烬和熔岩碎片的混合物,在喷发期间被强制喷射。

美国约翰霍普金斯大学地质学Assignment代写: 盾形火山

The shield volcano is a large volcano, usually a few miles in diameter and with a small slope on the side. Lava – Lava or liquid rock ejected during volcanic eruptions – Most of the volcanic eruptions in the shield are basalts with very low viscosity (poor mobility). Therefore, the lava flows easily and spreads over a large area. Shield volcanic eruptions usually involve long-distance propagation of lava and dispersion into thin slices. Therefore, over time, the volcanic mountains formed by the repeated flow of lava have a broad and gentle contour, away from the bowl-shaped depression called the crater on the mountain top. The height of the shield volcanoes is usually 20 times that of them, and when viewed from above, their names are similar to those of the ancient warriors’ circular shields. Some of the most famous shield volcanoes have been discovered in the Hawaiian Islands. The islands themselves were created by volcanic activity and there are currently two active shield volcanoes – the Kilauea and Mauna Loa volcanoes on the island of Hawaii. The Kilauea volcano erupts regularly, while Mauna Loa (pictured above) is the largest active volcano on Earth. It last broke out in 1984. Shield volcanoes are usually associated with Hawaii, but they can also be found in places like Iceland and the Galapagos Islands. Although the type of volcanic eruptions found in shield volcanoes may vary, most volcanic eruptions will erupt. The volcanic eruption is the most peaceful type of volcanic eruption, characterized by the stable production and flow of basalt lava, which eventually forms the shape of a shield volcano. Volcanic eruptions can occur at the top of the crater, or from the rift area – cracks and vents radiating from the top of the mountain. It is believed that these rift zone eruptions help to make the shape of the Hawaiian shield volcano more slender than other shield-shaped volcanoes, which are often more symmetrical. In the case of the Kilauea volcano, the volcanic eruptions in the eastern and southwestern rift regions are more than the apex, thus forming a lava ridge extending approximately 125 km east from the top of the mountain and 35 km southwest. Because lava from shield volcanoes are thin and flowing, gases such as steam, carbon dioxide and sulfur dioxide are the most common in lava water vapors – easily escape during volcanic eruptions. Therefore, shield volcanoes are less likely to explode, which is more common in composite and volcanic cone volcanoes. Similarly, shield volcanoes usually produce less volcanic debris than other volcanic types. Pyroclastic material is a mixture of rock, ash and lava fragments that are forced to eject during eruptions.

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