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Dangerous Ground or The Dangerous Ground is a large area in the southeast part of the South China Sea characterized by many low islands and cays, sunken reefs, and atolls awash, with reefs often rising abruptly from ocean depths greater than 1000m. There are few precise definitions, but Dangerous Ground corresponds roughly to the seas around the eastern half of the Spratly Islands. It is an oblong area running southwest to northeast for about 340 nautical miles (nm) (630 km), 175 nm (324 km) at its widest, with an area of about 52,000 nm² (178,000 km²).〔''Sailing Directions'' section 1.20, p. 8〕 It is west of Palawan island and northwest of the Palawan Passage. It lies approximately between 7.5–12°N, 113–117°E. The US NGA literature〔〔〔etc. seems to consider its centre as . The area is poorly charted, making it exceptionally dangerous to navigation – the major Singapore-to-Hong-Kong routes go well to the west〔http://www.oceangrafix.com/chart/zoom?chart=93022 Western SCS〕 and east〔 of the area: Due to the conflicting dates and accuracy of the various partial surveys of Dangerous Ground, certain shoals and reefs may appear on one chart, but not on another regardless of the scales involved. The water is a usually greenish-blue and is transparent to depths of on clear days.〔 ==Boundaries== The boundary of Dangerous Ground is shown on NGA charts 93044 (NW),〔http://www.oceangrafix.com/chart/zoom?chart=93044 NW Dangerous Ground〕 93045 (NE),〔http://www.oceangrafix.com/chart/zoom?chart=93045 NE Dangerous Ground〕 93046 (most of the SE),〔http://www.oceangrafix.com/chart/zoom?chart=93046 Most of the SE of Dangerous Ground〕 and 93047 (SW).〔http://www.oceangrafix.com/chart/zoom?chart=93047 SW Dangerous Ground〕 (The missing portion of the SE is covered by 93048〔Chart 93048 is not easily available on-line〕 and the top corner of 92006.〔http://www.oceangrafix.com/chart/zoom?chart=92006 SE Spratlys, Brunei, North Borneo and Southern Philippines〕) The area is described in NGA Pub. 161, ''Sailing Directions (Enroute) South China Sea and the Gulf of Thailand''.〔http://msi.nga.mil/MSISiteContent/StaticFiles/NAV_PUBS/SD/Pub161/Pub161bk.pdf Pub. 161, Sailing Directions (Enroute) South China Sea and the Gulf of Thailand, Fifteenth Edition, 2014, corrected to 15 November 2014.〕 Unfortunately, the two do not completely agree with each other as to the boundary. For example, the ''Sailing Directions'' include most of the NW area shown on Chart 93044 as outside of Dangerous ground, but exclude the Reed Bank, which is shown on Chart 93045 as inside Dangerous Ground. Both publications divide the area into four quadrants. ==NW== Chart 93044 – approx. 10–12°N, 113–115°E;〔 ''Sailing Directions'' pp8-10.〔 *1.21 North Danger Reef – northern and western sections * * North Reef, North Pass, Northeast Cay, Shira Islet, Middle Pass, Southwest Cay, West Pass (N), Jenkins Patches, West Pass (S) *1.22 North Danger Reef – southern and eastern sections; Trident & Lys Shoals * * South Reef, South Pass, Sabine Patches, Farquharson Patches, East Pass, Day Shoal, Iroquois Ridge; Trident Shoal, Lys Shoal *1.23 Thitu Reefs and surrounding * * Thitu Island, Subi Reef *1.24 Loaita Bank * * Loaita Island, Lankiam Cay *1.25 & 1.26 Tizard Bank * * Namyit Island, Gaven Reefs, Sand Cay, Itu Aba Island, Petley Reef, Eldad Reef *1.26 West of Tizard Bank * * Western Reef, Discovery Great Reef, Discovery Small Reef ==NE== Chart 93045 – approx. 10–12°N, 115–117°E;〔 ''Sailing Directions'' pp10-11.〔 *1.27 East of Loaita Bank * * Menzies Reef, Irving Reef, West York Island *1.27 Southampton Reefs (East of Tizard Bank) * * Hopps Reef, Livock Reef * Northern NE – Reed Bank * * Nares Bank, Marie Louise Bank *1.27 & 1.28 Central NE * * Jackson Atoll, Nanshan Island, Flat Island, Third Thomas Shoal, Hopkins Reef, Amy Douglas, Hirane Shoal, Hardy Reef *1.29 Eastern NE * *Sandy Shoal, Seahorse Shoal, Lord Auckland Shoal, Carnatic Shoal 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Dangerous Ground (South China Sea)」の詳細全文を読む スポンサード リンク
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