Diego Garcia is frequently subject to earthquakes caused by tectonic plate movement along the Carlsberg Ridge located just to the west of the island. One was recorded in 1812; one measuring 7.6 on the Richter Scale hit on 30 November 1983, at 23:46 local time and lasted 72 seconds, resulting in minor damage including wave damage to a 50-m stretch of the southern end of the island, and another on 2 December 2002, an earthquake measuring 4.6 on the Richter scale struck the island at 12:21 am.