Mountains and Hills

Korea's territory coincides with the Korean Peninsula. Between the peninsula and Manchuria flow, in opposite directions, the two largest rivers of the region, the Amnokgang (Yalu) and Dumangang (Tumen) both originating at Mt. Baekdusan (2,744 meters), the highest mountain throughout Korea and Manchuria. The Yellow Sea, the East Sea and the South Sea surround the other three sides of the peninsula, respectively.

Nearly 70 percent of the Korean Peninsula is covered by mountains and hills. Located mostly in the southern and western regions, the hills give way gradually to increasingly higher mountains toward the eastern and northern ends. On the whole, the western and southern slopes of the peninsula are wide with some plains and basins along rivers, while the eastern slope is very narrow because the high mountains hug the East Sea coastline.

Most of the high mountains are located along the Taebaeksan Range, which parallels the east coast, running roughly north-to-south. West of this range are the drainage basins of the Hangang and Geumgang rivers. This range is extended to the Nangnimsan Range in North Korea, forming the geological and geomorphological backbone of the peninsula and constituting the drainage divide between the western and eastern slopes of the peninsula. Mt. Nangnimsan (2,014 meters), Mt. Geumgangsan (1,638 meters), Mt. Seoraksan (1,708 meters), and Mt. Taebaeksan (1,567 meters) are some of highest summits along these ranges. Just southwest from the Taebaeksan Range is another important range, the Sobaeksan, which culminates in the massive Mt. Jirisan (1,915 meters). This range was historically a great barrier between the central and southern parts of the peninsula, and also between the eastern and western regions in the south. The so-called "Roof of Korea," the Gaema Plateau, located in the northwestern corner of the peninsula, has an average elevation of about 1,500 meters above sea level.

The landmass of the peninsula is rather stable geologically in spite of its proximity to Japan; it has neither active volcanoes nor strong earthquakes. There are, however, a few extinct volcanoes that were formed during the Pleistocene Age. Mt. Baekdusan is famous for a large caldera lake, Cheonji, meaning "Heavenly Lake." Mt. Hallasan in Jejudo Island, the highest mountain in South Korea, was recorded to have minor volcanic activities in the early 11th century. It has a small crater lake, "Baengnokdam," and there are about 400 parasitic cones in its piedmont.

About two-thirds of the Korean Peninsula is composed of pre-Cambrian metamorphic and granitic rocks. Although the distribution of sedimentary rocks is very limited, limestone is quite abundant in some regions and several limestone caves have developed, some of them very large and attracting tourists. Among the most famous caves are Gossigul, Gosugul and Seongnyugul, all of which are liberally decorated with stalagmites and stalactites.

Rivers and Plains

Most of major rivers flow into the Yellow Sea and a few into the Korea Strait, draining the western and southern slopes of the peninsula. Considering its geographical area, Korea has a relatively large number of large streams, six of them exceeding 400 kilometers in length. The discharge of rivers fluctuates very much due to the summer monsoon. In the summer rivers swell with heavy rainfalls, flooding valley plains every once in a while. In the other relatively dry seasons the water level drops quite low, and often much riverbed is exposed. Typhoons, which hit the southern part of the peninsula once every two or three years, also bring heavy rainfalls in late summer and early autumn.

In the past, rivers were important for transportation. Historical capitals such as Pyeongyang and Buyeo are located adjacent to major rivers, as is Seoul. After the introduction of railroads and automobiles, however, the importance of rivers for transportation means has deceased sharply, and rivers have begun to be used mainly for the irrigation of rice fields and the generation of electricity. During the last two decades a number of huge dams have been constructed for flood control, electricity and irrigation. But these dams have gradually begun to play a major role as reservoirs for large cities and industrial plants as a result of rapid urbanization and industrialization nationwide.

Most of plains are narrow floodplains developed along rivers, especially in the lower reaches. These plains are the major rice-producing landforms. Large tidal ranges at the mouths of major rivers flowing into the Yellow Sea inhibited the development of deltaic plains, although rivers transport large amounts of sediment during floods. Only the Nakdonggang River flowing into the South Sea has a small delta at its mouth. Erosional basins along rivers in areas of granitic rocks have also been important as agricultural regions since ancient times. Many large cities such as Chuncheon, Chungju and Wonju are located in such basins.

Geographical Regions

Mountain ranges have traditionally served as natural boundary markers between regions. Because these natural boundaries inhibited frequent interactions between peoples living on either side of the range, subtle, and sometimes substantial, regional differences developed in both the spoken language and custom of the people. These regional distinctions also correspond to the traditional administrative units devised during the Joseon Dynasty (1392-1910).

The Korean Peninsula is divided into three distinct regions; Central, South and North. These macro regions are divided into three separate geographical spheres, each of which comprises its own particular economic, cultural and physical distinctiveness. These include, in the Central region, the capital region of the Seoul metropolitan area, Chungcheong-do and Gangwon-do Province; in the South, Gyeongsang-do, Jeolla-do and Jeju-do Province; and in the North, Pyeongan-do, Hamgyeong-do and Hwanghae-do Province. The term "northern area" traditionally referred to those regions of Pyeongan-do and Hamgyeong-do Province prior to the division of the peninsula in 1945. The "North" now refers to all the areas north of the Demilitarized Zone (DMZ). In addition to Pyeongan-do and Hamgyeong-do Province, the North also includes Hwanghae-do and the northern parts of Gyeonggi-do and Gangwon-do Province.

Coasts

Korea has a long coastline compared to its land area, and coasts are divided into the east, west and south coasts. The east coast has small tidal ranges, a third of one meter at the most, and a relatively smooth shoreline with few islands offshore, because the Taebaeksan Range runs closely along the East Sea. Where mountains protrude from the Taebaeksan Range, coasts are rocky in general, but some beaches are found in places into which small streams carry sediment from the high mountains. In many instances the beaches take the form of sand spits and bars enclosing lagoons, notable features of the east coast. Along the coast between Wonsan and Gangneung are located a series of lagoons, of which Gyeongpo and Hwajinpo are among famous eastcoast resorts. Since the highway connecting Gangneung and Seoul was built in the 1970s, the east coast has been attracting tourists throughout the year, especially during the summer season.

The shorelines of the south and west coasts are very irregular with innumerable small peninsulas and bays as well as a large number of islands. The west coast faces the Yellow Sea, which is very shallow, and has large tidal ranges above 10 meters in some places. This has made it hard to develop harbors. Tidal flats are common coastal features especially in bays into which rivers discharge sediment during floods. Tidal flats have been reclaimed from ancient times, mainly for rice fields, but since 1970s the reclamation projects entered a new era in terms of magnitude. The Saemangeum Project, which is under construction as the largest such project ever undertaken in Korea, seeks to reclaim a total of 40,100 hectares of tidal flats with a length of 33 kilometers of huge dikes. It will be completed by 2011.

The south coast shows a typical ria shoreline, a coastal zone, which has been submerged. The length of coastline is nearly eight times longer than its straight-line distance, and its indentation is far greater than that along the west coast. The tidal ranges are relatively small at two to five meters, and tidal flats are not as wide as along the west coast. Although mountains face the sea, there are few beaches and sea cliffs along the mainland coast, because innumerable islands prevent the penetration of waves from offshore. Narrow straits between the mainland and islands are associated with extremely rapid tidal currents. At Uldolmok toward the western end of the south coast, tidal current reaches up to 13 knots.