411 REFERENCE · Wikibooks
Earthquakes/Basics of Earthquakes
Reference material by Wikibooks contributors. This retains its source identity and is not 411 news reporting.
According to Wiktionary, an earthquake (synonym "quake") is "a shaking of the Earth, caused by volcanic activity or movement around geologic faults" or "a natural disaster." This, indeed, comprehensively covers all written about earthquakes. However, you should learn something about this phenomenon's geography.
Most earthquakes occur along tectonic plate boundaries, although one of the worst earthquakes of all time was in Missouri, in 1811. It was felt even in Washington, D.C.