The Department of Earth and Ocean Sciences at the University of British Columbia defines geology as the study of the Earth and its composition, which includes the crust. A geologist covers everything from studying the times when dinosaurs roamed the Earth to predicting modern day earthquakes.
Geology is broken into many fields of studies, including volcanology, seismology and hydrology. The Earth's crust consists of 15 tectonic plates that are always on the move, and the continental and oceanic crust are the two types of crusts found on Earth. The oceanic crust is made of dense material, making it much heavier than the continental. This forces the continental crust downward where the two collide, where it eventually melts into magma far below the surface.