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  • 火山热点

    What does an intraplate eruption look like?
    ::板内喷发像什么?

    The Hawaiian Islands are formed from a  hotspot  beneath the Pacific Ocean.   grow above the hotspot.  Lava  flows down the hillsides, and some of it reaches the ocean, causing the islands to grow. Too hot now, but a great place in the future for  beach  lovers!
    ::夏威夷群岛由太平洋下方的热点形成,在热点上方生长。 岩浆从山坡上流下来,其中一些流到海洋,导致岛屿生长。 现在太热了,但对于海滩恋人来说,这是未来的大好地方!

    Volcanic Hotspots
    ::火山热点

    Some volcanoes form over active  hotspots . Scientists count about 50 hotspots on the Earth. Hotspots lie directly above a  column  of hot   called a  mantle plume . Mantle plumes continuously bring hot rock up from the mantle toward the  crust  ( Figure   ). The rock melts due to the release of pressure.
    ::一些火山形成于活跃的热点之上。 科学家数到地球上的大约50个热点。 热点直接位于热柱上方, 叫做人造羽流。 人造羽流不断将热岩从地壳上带到地壳上( 图 ) 。 岩石因压力释放而熔化 。

    Map showing global locations of volcanic hotspots, indicating varied eruption sizes and types.
     
    Mantle plumes are found all over the world, especially in the ocean basins. The size of the eruptions is different at different plumes.

    Hotspots may be in the middle of a tectonic  plate . They create intraplate volcanoes.
    ::热点可能位于地壳板块中间 形成板内火山

    Hotspots Within Oceans
    ::海洋中的热点

    Hotspots are much more common beneath ocean crust. This is because ocean crust is thinner. The plume can more easily penetrate this crust. As the tectonic plates move above a hotspot, they form a chain of volcanoes. The islands of Hawaii formed over a hotspot in the middle of the Pacific plate. The volcanoes are massive  shield  volcanoes that together create the islands. The lavas are  mafic  and have low  viscosity . These lavas produce beautiful ropy flows of pāhoehoe and clinkery flows of a'a. These lava types will be described in more detail in the concept " ."
    ::热点在海洋地壳下更为常见。 这是因为海洋地壳较薄。 羽流更容易渗透到地壳中。 当构造板块在热点上移动时, 它们形成火山链。 夏威夷岛屿在太平洋板块中间的热点上形成。 火山是巨大的屏蔽火山, 共同形成这些岛屿。 熔岩是大块的岩浆, 熔岩的粘度低。 这些熔岩产生美丽的pāhoehoe和a'a的结叶流。 这些熔岩类型将在概念中更详细地描述。 ”

    The Hawaii hotspot has been active for tens of millions of years. The volcanoes of the Hawaiian Islands formed at this hotspot. Older volcanoes that formed at the hotspot have eroded below  sea level . These are called the Emperor  Seamounts .
    ::夏威夷热点已经活跃了数千万年。夏威夷群岛火山在这个热点形成。在热点形成的老火山已经侵蚀到海平面以下。这些火山被称为皇帝海山。

    Lo'ihi seamount is currently active beneath the  water  southeast of the Big Island of Hawaii. One  day , the volcano will rise above sea level. Lo'ihi will join the volcanoes of the island or create a new island ( Figure   ).
    ::Lo'ihi海山目前活跃在夏威夷大岛东南方的水下。 有一天,火山将上升至海平面之上。 Lo'ihi海山将加入岛上火山,或创建一个新的岛屿(图 ) 。

    A bathymetric map of Lo'ihi seamount, showing depth variations and terrain features.
     
    A bathymetric map of Lo'ihi seamount. Lo'ihi will be the next shield volcano in the Hawaiian-Emperor chain.

    A hotspot beneath Hawaii is the origin of the voluminous lava produced by the  shield volcano  Kilauea, which can be viewed in this video.
    ::夏威夷下面的一个热点是屏蔽火山Kilauea产生的大量熔岩的起源,

     

     

    Hotspots may also be active at  plate boundaries . This is especially common at mid-ocean ridges. Iceland is formed by a hotspot along the Mid-Atlantic Ridge.
    ::热点也可能活跃在板块边界,这在洋中脊尤为常见,冰岛由大西洋中脊沿线的一个热点组成。

    Hotspots Within Continents
    ::各大洲内部的热点点

    Hotspots are found within continents, but not as commonly as within oceans. They are not common because it takes a massive mantle plume to penetrate the thick  continental crust . Eruptions from these hotspots are rare but massive. The Yellowstone hotspot is a famous example of a continental hotspot.
    ::热点存在于大陆内部,但不像在海洋内部那样常见。热点并不常见,因为它们需要巨大的地壳羽流才能穿透厚厚的大陆地壳。这些热点的暴发非常罕见,但规模很大。黄石公园热点是大陆热点的一个著名例子。

    Summary
    ::摘要

    • Volcanoes grow above hotspots. A hotspot is a zone of melting above a mantle plume.
      ::火山在热点上生长,热点是地壳羽流上方熔化的区域。
    • Hotspot volcanoes are better able to penetrate oceanic crust than continental crust. We see many more hotspot volcanoes in the oceans.
      ::热点火山比大陆地壳更能穿透海洋地壳,我们看到海洋中更多的热点火山。
    • Shield volcanoes commonly form above hotspots in the oceans.
      ::盾牌火山通常形成于海洋热点之上。

    Review
    ::回顾

    1. What causes melting at a hotspot?
      ::是什么导致热点融化?
    1. Describe how the Hawaiian hotspot formed a chain of volcanoes.
      ::描述夏威夷热点是如何形成火山链的
    1. Relative to the Hawaiian hotspot, where in the chain is the oldest volcano? Where is the youngest?
      ::与夏威夷热点相对,链条中最古老的火山在哪里?最年轻的火山在哪里?
    1. What do you think the future for Lo'ihi seamount will be?
      ::你觉得Lo'ihi海山的未来会是什么?

    Explore More
    ::探索更多

    Use the resource below to answer the questions that follow.
    ::利用以下资源回答以下问题。

     

     

    1. What is a hotspot?
      ::什么是热点?
    1. What does a thermal plume allow for?
      ::热羽流允许什么?
    1. What happens during convection?
      ::在对流过程中会发生什么?
    1. What carries the volcanoes away from a hotspot?
      ::什么把火山从热点移走?
    1. Why does the volcano subside when it moves off the hotspot?
      ::为什么火山在远离热点时会平息呢?