Plate tectonics is a geological theory according to which the Earth's crust (outermost layer, on which we live) is divided into a number of constantly moving plates (e.g., Indian, African, Eurasians, etc.). The motion of these plates causes volcanic activity, mountain and island formation, among other geologic activities. These distinct plates meet at plate boundaries, which are also the regions of intense volcanic activities. An example of plate movement related activity is the increasing elevation of Himalaya mountains. These mountains are along the meeting points of Indian and Eurasian plates and the constant motion of these plates is pushing these mountains up by about 2.4 inches/year. Another example of geologic actions of plate tectonics is the formation of Hawaiian islands. These islands were formed (and are continually being formed) as the pacific plate moves over a hotspot.
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