The boundary between the Indian and Asian plates is such an example of a collision plate boundary. The Himalayans are believed to be the result of this collision. When two plates converge in such a way that a heavier plate slides beneath a lighter plate, the plate contact is described as subduction . This rim of the Pacific is often referred to as the Ring of Fire . Diastrophism is a tectonic landform process that bends or breaks the earth.
Diastrophism includes the processes of warping, folding and faulting.
Warping is a relatively gentle bending of the earth over a large area. It results in the formation of surface domes and basins. Folding is a more severe bending of the earth in a more localized area. Usually, at the surface, an anticline shows as a ridge and a syncline shows as a valley. The area of the U.S. highly characterized by the process of folding is the central Pennsylvania mountains, an area known as the Ridge and Valley area.