Muirfield Seamount

The Muirfield Seamount is a submarine mountain located in the Indian Ocean approximately 130 kilometres (70 nautical miles) southwest of the Cocos (Keeling) Islands. The Cocos Islands are an Australian territory, and therefore the Muirfield Seamount is within Australia's Exclusive Economic Zone (EEZ). The Muirfield Seamount is a submerged archipelago, approximately 2.5 km in diameter and 16 - 18 m below the surface of the sea. A 1999 biological survey of the seamount performed by the Australian Commonwealth Scientific and Industrial Research Organisation (CSIRO) revealed that the area is depauperate.

The Muirfield Seamount was discovered accidentally in 1973 when the cargo ship MV Muirfield (a merchant vessel named after Muirfield, Scotland) was underway in waters charted at a depth of greater than 5000 m, when she suddenly struck an unknown object, resulting in extensive damage to her keel. In 1983, HMAS Moresby (1963), a Royal Australian Navy survey ship, surveyed the area where Muirfield was damaged, and charted in detail this previously unsuspected hazard to navigation.

The dramatic accidental discovery of the Muirfield Seamount is often cited as an example of limitations in the vertical datum accuracy of some offshore areas as represented on nautical chart especially on small-scale charts. More recently, in 2005 the submarine USS San Francisco (SSN-711) ran into an uncharted seamount about 560 kilometers (350 statute miles) south of Guam at a speed of 35 kn, sustaining serious damage and killing one seaman.