Seismology is the study of movements and vibrations within the earth, such as earthquakes and volcanoes. Seismologists also study vibrations caused by man, such as explosions from mine blasting and powerful bombs. Although seismology has not met with success in predicting earthquakes, seismologic studies have yielded a wealth of information about how and why earthquakes occur and about the Earth's interior.

The science of seismology was informally launched in 1760, five years after one of Europe's most devastating earthquakes at Lisbon, Spain. English geologist John Michell studied the event and suggested that earthquakes emit shock waves from within the earth. After noticing the close proximity of volcanoes and earthquakes, he proposed that earthquakes are caused by gaseous pressure produced by the boiling of water from volcanic heat. He also suggested that one could calculate the center of an earthquake by noting the time and duration of vibrations. Most of...