Seismology is a type of Earth science. It studies the origins and movements of seismic waves, or vibrations in the ground. Some seismic waves are generated in natural events. Earthquakes, for instance. Volcanoes are also a source. But seismic waves come from human activities, too — such as mining or weapons explosions. Seismic waves hold clues about the events that caused them. They can also reveal information about the structure and composition of Earth’s interior. Scientists who study these things are called seismologists.
Seismologists have many jobs. Some use seismic waves to understand earthquakes. This can help forecast earthquake risks in different areas. Others use seismic waves to map the inside of Earth and hard-to-reach places on Earth’s surface, such as ocean trenches. Seismic waves can be used to find underground pockets of oil or minerals. And they can reveal underground explosions caused by nuclear weapons tests. Detecting such explosions helps track who is following nuclear test bans, and who isn’t.