Topography

The notable topographical characteristic of the Korean peninsula is that it has a great many mountains. Mountains occupy 79.87% of its area and plains-20.13%.

Although the proportion of mountains is large, the average elevation above sea level is 440m, half as high as that of the Asian continent which is 950m, and well below that of the world’s land which is 875m. The mountain ranges are regular in their direction and heights. Major running trends of mountain ranges are mainly NNW-SSE, NE-SW and NNE-SSW.

Higher mountains are concentrated in the northern region and east coast area, their heights gradually being lower towards the west and south. Their elevation is

2,000 to 2,300m above sea level in the northern mountain regions and 1,400 to 1,600m in the eastern regions. The dissected depth of mountains is 500 to 1,500m

In the alpine areas, but 200 to 500m in the low mountain areas. This means that the mountainous regions are very much rugged in undulation.

It is the Post-Mesozoic tectonic movements that influenced the modern geomorphologic formation. As a result of active crustal movements at the beginning of the Mesozoic era, intensive changes took place in the geomorphologic development. During this period, intensive folding, faulting, intrusion of magma and volcanism became active in the East Asia including Korean Peninsula.

Because of the Songnim Disturbance that occurred first in the early Mesozoic era, large folds and nappe-thrusts with a E-W trend were formed in many places including regions throughout the South Pyongan Province and the Taebo Disturbance that occurred in the Jurassic period of the Mesozoic era resulted in the formation of the mountains and valleys with mainly NE-SW or NW-SE trends. With the return of a calm situation after the Taebo Disturbance, a new peneplanation took place. Towards the end of the Cretaceous era, faulting movements became active again, and the intrusions of magma occurred.

Entering the Cenozoic era, the crustal movement weakened noticeably, and the only the faulting, upheaval, subsidence occurred, resulting in the formation of grabens, basins and volcanic zones in scattered places. Such movements continued until the Quaternary of Cenozoic, and these movements caused intensive geomorphologic alternation. In this period were formed the mountain ranges constituting the backbone of of the Korean Peninsula such as the Hamgyong, Pujongryong, Rangnim and Taebaek mountain ranges, and Kaema and Ryongso Plateaus. By the volcanic activities which occurred along the fissure zones, were formed the Paektu Lava Plateaus, Singye-Koksan Plateau, Pyonggang-Cholwon Highland, Halla Mountain, Ullung Island and Tokto Island.

Therefore, the present geomorphologic featured of the Korean Peninsula are considered to be formed basically by the influence of the crustal movements that occurred mainly in the late Tertiary to the early Quaternary. At the beginning of the Quaternary period, the region of the West Sea of Korea subsided to form the topography of the west coast area. Even after the contour similar to that at present was formed, weak subsidence and upheaval movements continued in some parts of the coastal region at the beginning of the Quaternary period, and also by the action of waves and coastal currents the projecting parts were denuded to form cliffs, and fields were formed in the bay area with the accumulation of the alluvial deposition. And on the coasts of the West Sea and South Sea of Korea were formed broad tidelands Which are the marine sediments formed by the tidal current.

The geomorphology of mountainous regions of the Korean Peninsula is divided into the horst, dome block, folding, erosion and volcanic mountainous regions by their genetic origins.

Horst Mountainous region:

This is a region of mountains formed by the uplift of horst and the slopes of its outskirts are steep with cliffs in many places.

This region includes the Ahobiryong, Masinryong, Kwangju, Munsu, Chonma, Samgak, Pinandok and Chilbo mountain ranges.

Dome block mountainous region:

This is a region of mountains formed by the elevation of large blocks, and characterized by their comparatively even slopes.

To this category belong the mountain ranges such as the Rangnim, Ryonhwa, Puksubaek, Hamgyong, Pujonryong and Chongryong

Folding Mountainous region:

This is an anticlinal mountainous region formed by folding, and its ridges are smooth and extends in the direction of its folding axis. To this kind belong the Puktaebong, Jang-an, Myorak, Chonsong, Jongbang, Pultha, Sudae and Roryong mountain ranges.

Erosion mountainous region:

This is a mountainous region consisting of rocks of high resistance to erosion and of densely developed valleys.

The Jamo and Kangdong mountainous areas are typical.

Volcanic mountainous region:

This is a mountainous region formed by volcanism, and is composed of volcanic cones and volcanic plateaus. It includes the Paektu Volcano, Paektu Lava Plateau, Chilbo Volcano, Singye-Koksan Plateau, Pyonggang-Cholwon Highland, Halla Mountain and Ullung Island.

Plains are distributed in the west and south coast regions of the Korean Peninsula.

The area of plains is 44,727squarekilometers(20.13% of the total area). Plains are developed mainly in major river basins and coastal regions. From the point of view of genesis they are all classified as developed denudation, river and marine deposit plains, but their sizes are not very large.

For example, the denudation plains include the Pyongyang(950 square kilometers), Pakchon(100 square kilometers), Seoul(600 square kilometers), Kimpo(600 square kilometers), Pyongtaek(850 Square kilometers), Kimhae(240 square kilometers), Jonnam(950 square kilometers) Honam)1,850 square kilometers). Ronsan(500 square kilometers) and Naepho Plains(230 square kilometer).

The deposit plains are represented by the Jseryong(1,300 square kilometers), Yeonbaek(1,150 square kilometers), Hamhung(600 square kilometers), Hamhung(600 square kilometers), Kumya(400 square kilometers), and Susong Plains. The marine deposit plains comprise the Ryongchon(450 square kilometers), Yoltusancholli(750 square kilometers), Unjon(180 square kilometers), and Onchon Plains(500 square kilometers).

Rivers in the Korean Peninsula are mainly developed along fault belts caused by the tectonic movement in the Mesozoic era. After that though they were partly altered by peneplanization and Cenozoic tectonic movement during a long period of time main water path directions are succeeded. The river framework was formed while the vertebral mountain ranges, which are the main watersheds, were forming due to the valuted upheaval movement and subsiding movements in the East and West Seas of Korea that occurred throughout the Korean Peninsula in Miocene to Pliocene, so that the slopes were separated towards the east, west and south seas.

There are 1,458 rivers each with the length of 5 to 10km, and they account for 60% of the total; and 689 rivers each with the length of 11 to 20km, which occupy 26.2%. The Amnok, Tumen, Taedong, Rakdong and Han rivers are more than 400km each in length and they have been called five major rivers of Korea. Only the Amnok River has a basin of over 60,000 square kilometers, the basin areas of the Tumen, Taedong, Rakdong and Han Rivers are 40,000 to 60,000 square kilometers each; the Chongchon, and Kum Rivers have respectively a basin area of some 10,000 square kilometers. The Kumya, Ryesong, Seomjin Rivers drain an area of 3,000 to 5,000 square kilometers, and other rivers smaller areas. Rivers in the norther half of Korea are extensively utilized for the development of of the national economy, namely, for power generation, irrigation and water transport. In particular, the West Sea, Mirim, Ponghwa and Hadan Barrages have been constructed across the Taedong River for a rational use of its water. Among them, the West Sea Barrage has formed an artificial lake on the roadstead 8km off the coast, a peerless gigantic structure created by Juche Korea.

There are more than 20 lakes each with an area of at least 1 square kilometers in our country. Lakes are divided by origin into ones formed by volcanism and tectonic movements, as well as lagoons, oxbow lakes.

Lakes originated by volcanism and tectonic movements are Lake Chon on Mt. Paektu and Lakes Samji, Jangyon and Paengnok.

Lake Chon is a natural lake on the top of Mt. Paektu, the sacred mountain of revolution. It has a surface area of 9.16 square kilometers. It is 14.4 km in circumference, its width is 4.6km at the widest, and 3.6km at the narrowest. Its greatest known depth is 384m, its surface elevation above the sea level 2,194m, around the lake high crests of over 2,600m soar, among them, Janggun Peak(2,750m), and cliffs as high as 500m surround it like a folding screen. Lakes Kwang, Man, Chonma and Tongjong belong to the lagoon type. Jokji, Hukji, Hyondamji in the lower reaches of the Tumen River are of the Oxbow lake category.

Korea is a maritime country which is seabound on three sides. All the seas adjoining it are connected with the Pacific. The waves and currents that steadily change the coastal features of the Korean Peninsula are eroding continuously the rock base of the land on its coasts, and depositing most of silt carried down by rivers on the seashore. This process has changed slowly the coastal features. The coast line has basically two directions, namely, NE-SW and NW-SE directions, which correspond to the tectonic directions. It is characteristic that these directions stretch into the inner part of peninsula to form land features by them. Thus basic directions of the coast lines are defined by the tectonic directions, particularly by the deep-faulted zones.

There are 4,198 islands around the Korean Peninsula, of which 267 are located in the East Sea of Korea, 2,513 in the West Sea of Korea and 1,418 in the South Sea of Korea.

The East Sea of Korea is the largest and deepest of them. The East Sea of Korea is 978,000square kilometers wide, 1,619,000 km3 in volume, 1,668.2m deep on an average and 3,699.0 m at the deepest. The waters of the East Sea of Korea is bounded on the east by the line connecting the Tappi Cape of Honshu, Shirakami and Soya Capes of Hokkaido in Japaan, and the Kurilion Cape of Sakhalin Island of Russia, on the south by the line linking the Kanjol Cape of the East Sea of Korea in Korea and Kawajiri Cape of Honshu in Japan, on the north, by the line linking Nepursku and Wahu Capes of the Tater Strait in Russia. There are not many peninsulas, bays, and islands in the East Sea of Korea. The Hodo peninsula, Yong-il peninsula, Gulf of East Korea, Rajin Bay, Kimchaek Bay, Wonsan Bay, Ullung Island, Mayang Island and Tok Island(Dokdo) are comparatively large ones. The cold North Korean Current flows from the north, the warm East Korean Current flows to the north from the south. The difference in flood and ebb is extremely small. Its average difference is 0.2m at Wonsan.

The West Sea of Korea is a continental shelf sea formed by marine transgression into a wide basin. The coastline usually intersects perpendicularly the mountain ranges. So the coastline is highly indented, the sea is shallow, and there are a great many islands.

The West Sea of Korea covers the waters north of the line linking the Haenam Cape on the southwestern coast of the Korean Peninsula and the Bei Cape on the estuary of the Yantze River, China. The West Sea of Korea occupies an area of 437,300.70 square km,

The volume of which is 17,299 km3, average depth 39.3m, and the greatest depth 118m. Here are many peninsulas, bays and islands. Slightly warm current, West Korean Current, flows in the West Sea of Korea. The difference in flood and ebb is 5.7m at Inchon, 3.9m at Nampho. The South Sea of Korea is next in size to the East Sea of Korea. It covers an area of 822,736 square km, its volume is 363,654 km3, its average depth 442m, and the greatest depth 2,999m. It covers the waters south of the East and West Seas of Korea.

There are developed tidal flats in the Korean Peninsula. Their geomorphologic inclination is very gently and flat, with a sloping degree of a thousandth to three thousands. These flats stretch as far as 12km towards the sea, covering an area of 720,000 hectares.

The continental shelf occupies a total area of 1,249,000 square kilometers, of which the continental shelf of the East Sea of Korea covers an area of 189,000 square kilometers, that of the West Sea of Korea 437,300 square kilometers, that of the South Sea of Korea 623,447 square kilometers.

Situated between the Asian continent and seas adjoining to the Pacific Ocean, the Korean Peninsula is under the influence of the oceanic and continental climate. Therefore, the Korean Peninsula belongs to the temperate zone, where the four seasons are conspicuous, its annual average temperature being 8 to 12 C, average precipitation 1,000 to 1,200mm a year. The climate of the Korean Peninsula is a typical monsoon climate, thus in winter dry and cold N-NW wind blows, clear weathers continue, but in summer the south and south-east winds bear warm and damp air from the Pacific Ocean so that rainy and hot weather continues. Therefore, precipitation in winter is only about 15% of the yearly total, but during three summer months 50-60%. Continental and marine monsoons alternate in spring and autumn, the direction of wind is not constant, and warm and fine weather is predominant.

The climate of the Korean Peninsula is characterized by a great variety in comparison with the size of its area. It is related to the fact that the peninsula is a long stretch from north to south across middle latitudes with a great latitudinal difference in the amount of sun radiation, and has a complex geomorphology including the shapes of mountain ranges. Because the peninsula is situated in various climate zones ranging from sub-tropical zone of the south sea coast to the sub-frigid zone of the high mountainous region in the northern tip, its temperature and precipitation vary from place to place.

Climate

DPR Korea has a temperate climate with distinct seasonal changes. The overall annual temperature is between 8 and 12 degrees centigrade. The rainfall is moderate, average annual precipitation being 1120mm; the rainfall is particularly profuse in summer and there are distinct dry and rainy seasons.

DPR Korea is alternately visited by different air-currents causing climatic variations according to season. While summers can be very humid, spring and autumn have relatively warm and clear weather with little rainfall. Winter in DPRK Korea can be quite severs with night temperature falling 25 degrees on the centigrade scale below the freezing point.