At the Earth's surface, earthquakes manifest themselves by a shaking and sometimes displacement of the ground. When a large earthquake epicenter is located offshore, the seabed sometimes suffers sufficient displacement to cause a tsunami. The shaking in earthquakes can also trigger landslides and occasionally volcanic activity.
In its most generic sense, the word earthquake is used to describe any seismic event—whether a natural phenomenon or an event caused by humans—that generates seismic waves. Earthquakes are caused mostly by rupture of geological faults, but also by volcanic activity, landslides, mine blasts, and nuclear experiments.
Ten worst earthquakes in history:
- 1556, January 23 Senshi Province, China = Over 830,000 Dead
- 1976, July 28 Tangshan, China = Over 242,000 Dead
- 1920, December 16 Kansu, China = Over 180,000 Dead
- 1923, September 1 Toyko-Yokihama, Japan = Over 140,000 Dead
- 1290, September 27 Gulf of Chihli, China = 100,000 Dead
- 1693 Catania, Sicily and Naples, Italy = 60,000 and 93,000, respectively Dead
- 1667, November Shemakha, Caucasia = 80,000 Dead
- 1908, December Messina, Italy = 75,000 to 80,000 Dead
- 1932, December 26 Kansu, China = 70,000 Dead
- 1970, May 31 Northern Peru = 50,000 to 70,000 Dead