因此,[这][1]。相对(小板)[2]板块俯冲在南美大陆。(俯冲大洋板块)[3]包含了水,挤出压力,开始上升。水(液体)一般(低熔点)[4],所以热软流层以上冷俯冲板块(部分融化)[5],岩浆,更多的移动,开始上升,最终到达水面,形成一个(火山弧)[3],草图suurface俯冲带。为什么有火山在俯冲板块的某些部分,而不是别人?这是一个临时状态。目前(脊俯冲][6]在这些区域。这些山脊是温暖的,没有心情比周围的板,他们不通过软流层但幻灯片(经过短暂的下降)(附近)在大陆地壳水平。在过去,在这些区域火山活动当陡俯冲。所以,是的,俯冲是整个故事,但俯冲作用的类型。 The last link describes the current understanding of how these areas with volcanism will shift with subduction of the ridges, as well as sketches of the subduction types, as pictured by seismics. Hope that makes some sense. The volcanists among us may have a better answer :-) [1]: https://en.wikipedia.org/wiki/Andean_Volcanic_Belt [2]: https://en.wikipedia.org/wiki/Nazca_Plate [3]: https://en.wikipedia.org/wiki/Continental_arc [4]: http://www.tulane.edu/~sanelson/Natural_Disasters/volcan&magma.htm [5]: https://en.wikipedia.org/wiki/Partial_melting [6]: http://www.geo.umass.edu/structure/StrSem/Ramos-Folguera-GSL-Spec-Pub-2009.pdf