Earthquakes are among the most deadly natural hazards. There are around 100 earthquakes each year of a size that could cause serious damage.
Earthquakes strike without warning and many of the Earth’s earthquake zones coincide with areas of high population density. When large earthquakes occur in such areas the results can be catastrophic, with terrible loss of human lives and untold economic cost.
Seismology is the study of earthquakes and seismic waves. The seismograph records the seismic waves generated by earthquakes, allowing the seismologist to determine where , and how deep, a particular earthquake is.
Also, the seismic waves from earthquakes can be used to image the deep interior of the Earth, providing vital clues to the internal structure of our planet.
These pages will explain what an earthquake is: