Plate Tectonics: The theory explaining the structure of the earth's crust and many associated phenomena as resulting from the interaction of rigid lithospheric plates that move slowly over the underlying mantle.
Erosion: The process by which wind, water, ice or gravity transports soil and sediment from one location to another.
Natural Disaster:A major adverse event resulting from natural processes of Earth; examples include floods, hurricanes, tornadoes, volcanic eruptions etc.