KAMCHATKA (kahm-chatla), a province of the Far East ern area, Russian S.F.S.R., including the peninsula of Kamchatka, and also that part of the mainland lying north of Cape Viligin (north of the town of Tumansk in 6o° 4o' N., 156° so' E.), and east of a line going along the crest of the mountain range, and then across the ridge into the valley leading to Chaun Bay, west of the Pala river. The Arctic Ocean washes its northern shores from Chaun Bay eastwards, the Bering Strait, the Bering Sea and the Pacific Ocean its eastern shores, and the sea of Okhotsk its western shores.
The two main ranges are the Central and the Eastern. The Central range (3,00o ft.), slopes sharply on the east to the upper Kamchatka river valley, but runs down to the sea on the west in long, low spurs. The Eastern or Miakovski range (4,000 to 4,800 ft.), a rugged mass containing many isolated volcanic peaks, is merged with the Central range around Lake Palanskoe north of the sources of the Tigil river in a confused mountain mass nearer to the west than the east coast, and from this point the Tigil Spur branches off from the Central range. North of the Lyesnaya river at the neck of the peninsula, the single range dies down, with the tundra covered plateau of the Parapolski to the north-west, and gentle slopes to the south-east. The Kamchatka river after flowing north for some distance between the Central and the Eastern chains turns eastward through a gap in the Eastern range. The Central and Eastern ranges towards the south approach one an other, being separated by the Ganal tundra (1,200--1,300 ft.).
South of this is a valley, with the Bistraya river flowing westward through it to join the Bolshaya river and south of this the penin sula is wild and rugged, with many volcanic peaks, and, as in the region farther north, a gentler slope westwards than eastwards.
The most striking feature of the peninsula is, however, the series of towering volcanoes which stretches on the east from Cape Lopatka to the neighbourhood of Syedanka, forming part of the Pacific ring of volcanic activity extending from Java and the Philippines, through Japan, the Kuril islands, Kamchatka and the Aleutian islands to North America. Forty volcanoes, 14 active and 26 extinct, have been located in Kamchatka, and more may be discovered when the peninsula has been completely surveyed.
Signs of former volcanic activity are known to exist elsewhere; e.g., the Lyesnaya district. Volcanic activity is spasmodic and peaks believed to be extinct suddenly break out again; e.g., the violent eruption of Koryatskaya (alt. 11,522 ft.) north of Petro pavlovsk in 1895. Kluchevskaya (alt. 16,130 ft.) is the highest peak in Siberia and the highest active volcano in the old world.
It is surrounded by several rows of terraces and lesser peaks and the circumference of its base measures about zoo m. It is in a state of continuous activity, and notable eruptions occurred in 1729, 1841, In 1853 its lava outflow reached the Kamchatka river. Other volcanic peaks are Kronots kaya (alt. 10,808 ft.), Shiveluch (alt. 10,519 ft.), in the Yelovka district and Krestovskaya (alt. 9,392 ft.). In the north the moun tains consist chiefly of Tertiary sandstones and interbedded vol canic rocks, thick Tertiary deposits, probably Miocene, overlie the middle portions of the west coast. The southern parts of the peninsula are mainly granites, syenites, crystalline slates and recent volcanic deposits. Extensive layers of melaphyre and andesite, with conglomerates and volcanic tuffs, cover the middle portions. In 1899 glaciers were discovered on the Byelaya and Utkinskaya mountains (15,4o0 ft.).