Hikermor has it right. Marine sedimentary rocks which have been uplifed by tectonic forces comprise many of the great mountain ranges of the world. Even Mt Everest is composed of rocks that were once (a very long time ago) deposited under the sea. Paleoseismology, the subset of geology which finds indications of ancient earthquakes, is a relatively recent development. Finding indications of ancient tsunamis is an even younger science. Both have become very important for disaster planning, and for permitting infrastructure development.