And the other islands, well, the farther away from the plume they are now, the older they are, and the longer ago their volcanoes went dormant or extinct.Incidentally, volcanic islands may seem small,but the island known as the Big Island Hawaiiis one of the tallest topographic features on the planet, more than five kilometers from the sea floor to the ocean surface,and almost that much again, up to its highest peak.That’s nearly ten kilometers from ocean floor to the highest point on the island, which makes it taller even than Mount Everest.So, you can imagine the huge amounts of magma, or lava, that’ve flowed up to form even just this one island, much less the whole chain of islands.Now, the Plume Hypothesis provides a pretty elegant explanation for a volcanic anomaly, like the Hawaiian Islands.But, while it’s hypothetically attractive, there’s very little direct evidence to support the theory, because so far,no one’s been able to actually observe what’s happening that far beneath the Earth’s crust.Some studies have been done, seismographic, geochemical, where the data’s consistent with the model, but they aren’t definitive proof.
而其他岛屿，它们现在离地幔柱越远，形成的时间就越长，它们的火山沉寂或熄灭的时间就越早。偶尔火山岛看上去也许很小，但是像夏威夷这样知名的大岛是地球上最高的地形特征之一，从海床到海平面超过5千米，从海平面到其顶峰差不多也有那么高。从海床到这座岛的最高点将近有一万米，这使得它甚至比喜马拉雅山还要高。所以不难想象出喷涌而出形成这一座岛的岩浆数量之巨大，更不用说这整个群岛。地幔柱理论为像夏威夷群岛这样的异常火山提供了一个非常得体的解释。但是，虽然这个理论很有吸引力，但是几乎没有直接证据能够支持这一理论，因为到目前为止，没人能够真正观察到那么深层的地壳在发生什么。人们进行了一些地震学、地球化学方面的研究，这些研究中得出的数据和模型是一致的，但是它们不是最可靠的证据。
暂无注释
