< p >没有一个集中的板块,而相反的!< / p > < p >“火环”真的是一种模式。它是伴随着俯冲带。所以问题就变成了,“为什么太平洋俯冲带包围?”。< / p > < p >回想泛大陆。这是一个超大陆,形成于晚古生代。地球上几乎所有的陆地被集中在一个大的超级大陆。当这个分手了,新大洲离开对方。快进200毫安左右,你会发现,到目前为止,大陆已经分开,他们现在聚集在一个点在地球的另一边——大陆正在向彼此!Hence the remains of the super ocean (which was actually multiple ocean plates - today's Pacific & Nazca plates, plus the Farrallon plate (RIP),etc ) is shrinking as the continental plates move towards it. This destruction of the ocean plate(s) occurs at subduction zones. This is a big picture generalisation. Not all of the Pacific's boundaries are marked with subduction zones (e.g. North America has two large strike slip systems + a new spreading ridge). Also, not all of the continents are converging on each other. Africa is doing a pirouette, India is moving northwards, etc.