Korea comprises theKorean Peninsula (the mainland) and 3,960 nearby islands. The peninsula is located inNortheast Asia, betweenChina andJapan. To the northwest, theYalu River separates Korea from China and to the northeast, theTumen River separates Korea from China andRussia. TheYellow Sea lies to the west, theEast China Sea andKorea Strait to the south, and theSea of Japan (East Sea) to the east.[1] Notable islands includeJeju,Ulleung, and theLiancourt Rocks.
At 223,179 km2, the area of Korea is similar to the area of theUnited Kingdom (244,100 km2) or theU.S. state ofMinnesota (225,171 km2). Excluding the islands, the area of theKorean Peninsula is 220,847 km2. The peninsula measures approximately 1,000 km (620 mi) from north to south and 300 km (190 mi) from east to west.[2]
Mountains cover 70 percent of Korea, especially in the eastern and northern parts. Well-developed arable plains, mostly in southern and western parts of the peninsula, are generally small and separated by successive mountain ranges.
The highest mountains are in the northeast.Mount Paektu, a dormant volcano on the border with China, is the highest mountain in Korea at 2,744 m (9,003 ft).[2] The southern extension of Mount Paektu, a highland calledKaema Plateau, was mainly raised during theCenozoicorogeny and partly covered by volcanic matter. It is bounded by theRangnim Mountains to the west and theHamgyong Mountains to the east.
The principaldrainage divide (namedBaekdu-daegan) runs north to south, beginning with the Rangnim Mountains bisecting the north and continuing down the eastern side of the peninsula as theTaebaek Mountains. Several lower, secondary mountain ranges, including theKangnam Mountains andSobaek Mountains run southwest from the main dividing range.[3] They developed along the tectonic line ofMesozoic orogeny. Some significant mountains includeMount Sobaek (1,439 m or 4,721 ft),Mount Kumgang (1,638 m or 5,374 ft),Mount Seorak (1,708 m or 5,604 ft),Mount Taebaek (1,567 m or 5,141 ft), andMount Jiri (1,915 m or 6,283 ft).
Unlike most ancient mountains on the mainland, many important islands in Korea were formed by volcanic activity in the Cenozoic orogeny. Jeju Island, situated off the southern coast, is a large volcanic island whose main mountain,Mount Halla (1,950 m or 6,398 ft), is the highest in South Korea.[2] Ulleung Island is a volcanic island in the Sea of Japan whose composition is morefelsic than Jeju. The volcanic islands tend to be younger, the more westward.
Because the mountainous region is mostly on the eastern part of the peninsula, the mainrivers tend to flow westwards. Two exceptions are the southward-flowingNakdong River andSeomjin River. Important rivers running westward include the Amnok River, theChongchon River, theTaedong River, theHan River, theGeum River, and theYeongsan River.[4] These rivers have extensivealluvial plains and provide an ideal environment forwet-rice cultivation.
The peninsula has 8,460 km (5,260 mi) of coastline. The southern and southwestern coastlines of Korea are particularly irregular, forming a well-developedria coastline, and most of Korea's small islands are found here. This convoluted coastline results in mild seas and a calm environment allowing for safe navigation, fishing, andseaweed farming. The Yellow Sea on the western coast has an extremely hightidal range – atIncheon, around the middle of the western coast, it can get as high as 9 m (30 ft). This has led to broadmudflats along the south and west coasts.[4] In contrast, the east coast facing theSea of Japan (East Sea) is steep and mostly straight, with sandy beaches.[5]
The terrain of Korea is rumpled, covered with low mountains. Most rocks are ofPrecambrian origin, although isolated pockets ofPaleozoic,Mesozoic, andCenozoic rock can also be found.
There are no active volcanoes on the peninsula. However,Baekdu Mountain in the north andHallasan in the south havecrater lakes, indicating that they were active not long ago. Furthermore,hot springs indicative of low-level volcanic activity are widespread throughout the peninsula. Roughly two earthquakes are recorded per year, but few have any major impact.
The climate of Korea differs dramatically from north to south. The southern regions experience a relatively warm and wet climate similar to that ofJapan, affected by warm ocean waters including theEast Korea Warm Current. The northern regions experience a colder and to some extent more inland climate, in common withManchuria. For example, the annual precipitation of theYalu River valley (600 mm or 24 in) is less than half of that on the south coast (1,500 mm or 59 in).[6] Likewise, there is a 20 °C (36 °F) difference in January temperature between the peninsula's southern and northern tips.
The entire peninsula, however, is affected by similar climatic patterns, including theEast Asian Monsoon in midsummer and frequent typhoons in autumn. The majority of rainfall takes place during the summer months, with nearly half during the monsoon alone. Winters are cold, with January temperatures typically below freezing outside ofJeju Island. Winter precipitation is minimal, with little snow accumulation outside of mountainous areas.
Surveys of Korean flora have identified more than 3,000 species on the peninsula, of which more than 500 areendemic. The peninsula'sfloristic provinces are commonly divided between warm-temperate, temperate, and cold-temperate zones. The warm-temperate zone prevails over the southern coast and islands, includingJeju-do. It is largely typified bybroad-leavedevergreens.
The temperate zone covers the great majority of the peninsula, away from the southern coast and high mountains. It is dominated by theKorean pine and various broad-leaved deciduous trees. Cold-temperate vegetation is found along the peninsula's northern fringe and in the high mountains, including the upper reaches ofHallasan on Jeju. Evergreens in this area includelarch andjuniper. Much of this vegetation is shared with Manchuria.
According to theWorld Wide Fund for Nature, Korea consists of severalecoregions. TheSouthern Korea evergreen forests occupy the southernmost portion of the peninsula, as well as the island ofJeju. TheCentral Korean deciduous forests occupy the more temperate central portion of the peninsula.Manchurian mixed forests occupy the northern lowlands and low hills of the peninsula, and extend north intoManchuria as far as theAmur River on the Russia-China border. TheChangbai Mountains mixed forests include the higher elevation mountain region along the North Korea-China border, where forests are dominated by conifers, withalpine meadows and rock slopes on the highest peaks.[7]
