sustain (sustains 3rd person present) (sustaining present participle) (sustained past tense & past participle) 1 verb If you sustain something, you continue it or maintain it for a period of time. But he has sustained his fierce social conscience from young adulthood through old age... V n. ...a period of sustained economic growth throughout 1995.
If oceanic and continental crust collides the denser one which is the oceanic crust will be subducted, go underneath, the continental crust. The high heat of the mantle causes the oceanic crust to melt into magma. If the crust gets cracked this allows magma to rise and come out of the crust as lava which will form Volcanoes. When two continental crusts collide, the crust is forced to go upwards which forms mountains.
One is the continental crust (under the land) and the other is oceanic crust (under the ocean). The continental crust is thicker, and the oceanic crust is thinner. The thickness of the crust varies from 5 to 70 kilometers. The temperature of the crust increases with depth because of geothermal energy.