Editing Diego Garcia (section)

===Geography===
[[File:Biot-travel-svg-map.svg|thumb|A location map of Diego Garcia]]
Diego Garcia is the largest land mass in the Chagos Archipelago (which includes [[Peros Banhos]], the [[Salomon Islands]], the [[Three Brothers (islands), Chagos|Three Brothers]], the [[Egmont Islands]], and the [[Great Chagos Bank]]), being an atoll occupying approximately {{convert|174|km2|sqmi|sigfig=2}}, of which {{convert|27.19|km2|sqmi|sigfig=2}} is dry land.<ref>[[#NRMP|Natural Resources Management Plan (2005)]], paragraph 2.4.1.</ref> The continuous portion of the atoll rim stretches {{convert|64|km|sigfig=2|abbr=on}} from one end to the other, enclosing a lagoon {{convert|21|km|0|abbr=on}} long and up to {{convert|11|km|0|abbr=on}} wide, with a {{convert|6|km|0|adj=on|abbr=on}} pass opening at the north. Three small islands are located in the pass.<ref name="ReferenceA"/>

The island consists of the largest continuous dryland rim of all atolls in the world. The dryland rim varies in width from a few hundred metres to 2.4&nbsp;km. Typical of coral atolls, it has a maximum elevation on some dunes on the ocean side of the rim of {{convert|9|m|ft|abbr=off}} above mean low water. The rim nearly encloses a lagoon about {{convert|19|km|mi|abbr=on}} long and up to {{convert|8|km|mi|abbr=on}} wide. The atoll forms a nearly complete rim of land around a lagoon, enclosing 90% of its [[perimeter]], with an opening only in the north. The main island is the largest of about 60 islands which form the Chagos Archipelago. Besides the main island, three small islets are at the mouth of the lagoon: West Island ({{convert|3.4|ha|acre|abbr=on}}), Middle Island ({{convert|6|ha|acre|abbr=on}}) and East Island ({{convert|11.75|ha|acre|abbr=on}}). A fourth, Anniversary Island, 1&nbsp;km (1,100 [[yards]]) southwest of Middle Island, appears as just a sand bar on satellite images. Both Middle Island and Anniversary Island are part of the Spur Reef complex.<ref name="ReferenceA">[[#NRMP|Natural Resources Management Plan (2005)]], paragraph 2.5.1.</ref>

The total area of the atoll is about {{convert|170|km2|sqmi|sigfig=2|abbr=on}}. The lagoon area is roughly {{convert|120|km2|sqmi|sigfig=2|abbr=on}} with depths ranging down to about {{convert|25|m|ft|abbr=on}}. The total land area (excluding peripheral reefs) is around {{convert|30|km2|sqmi|sigfig=2|abbr=on}}. The coral reef surrounding the seaward side of the atoll is generally broad, flat, and shallow around {{convert|1|m|ft|abbr=on}} below mean sea level in most locations and varying from {{convert|100|to|200|m|ft|abbr=on}} in width. This fringing seaward reef shelf comprises an area around {{convert|35.2|km2|sqmi|sigfig=2|abbr=on}}. At the outer edge of the reef shelf, the bottom slopes very steeply into deep water, at some locations dropping to more than {{convert|450|m|ft|sigfig=2|abbr=on}} within {{convert|1|km|mi|abbr=on}} of the shore.<ref name="ReferenceA"/>

In the lagoon, numerous coral heads present hazards to navigation. The shallow reef shelf surrounding the island on the ocean side offers no ocean-side anchorage. The channel and anchorage areas in the northern half of the lagoon are [[dredge]]d, along with the pre-1971 ship [[turning basin]]. Significant saltwater wetlands called [[barachois]] exist in the southern half of the lagoon. These small lagoons off of the main lagoon are filled with [[seawater]] at high tide and dry at low tide. Scientific expeditions in 1996 and 2006 described the lagoon and surrounding waters of Diego Garcia, along with the rest of the Chagos Archipelago, as "exceptionally unpolluted" and "pristine".<ref>{{cite web|url=http://www.chagos-trust.org/science.asp |title=Science of the Chagos – Chagos Conservation Trust |access-date=16 June 2009 |url-status=bot: unknown |archive-url=https://web.archive.org/web/20090616185943/http://www.chagos-trust.org/science.asp |archive-date=16 June 2009 }}</ref>

Diego Garcia is frequently subject to earthquakes caused by [[Plate tectonics|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&nbsp;am.<ref name="realhistory" />{{Better source needed|date=July 2023}}

In December 2004, [[2004 Indian Ocean earthquake and tsunami|a tsunami generated near Indonesia]] caused minor shoreline erosion on Barton Point (the northeast point of the atoll of Diego Garcia).<ref>[http://www.reefnewmedia.co.uk/cmt_chagos/uploads/PDF/Newsletters/ChagosNews25.pdf Chagos News, No. 25, p. 2] {{webarchive |url=https://web.archive.org/web/20120119025950/http://www.reefnewmedia.co.uk/cmt_chagos/uploads/PDF/Newsletters/ChagosNews25.pdf |date=19 January 2012 }}</ref>