The Okhotsk plate is a minor tectonic plate covering the Kamchatka Peninsula, Magadan Oblast, and Sakhalin Island of Russia; Hokkaido, Kantō and Tōhoku regions of Japan; the Sea of Okhotsk, as well as the disputed Kuril Islands.
Japan's principal fault system is the zone where the Amur plate, the Eastern edge of the Eurasian plate, meets the Okhotsk plate, sometimes considered the Western edge of the North American plate.
The Sakhalin Island Arc (Russian Сахалинские острова) is an ancient volcanic arc dating from the Early Miocene. The arc was a result of the Okhotsk Plate subducting beneath the Eurasian Plate in the convergence zone. The arc runs from mainland Asia through Sakhalin Island into central Hokkaido and the collision zone around the Daisetsuzan Volcanic Group, where the Kuril Island Arc and the Northeastern Japan Arc meet.
North Asia or Northern Asia (Russian: Северная Азия) is the northern region of Asia, which is defined in geographical terms and consists of three federal districts of Russia: Ural, Siberian, and the Far Eastern. North Asia is bordered by the Arctic Ocean to its north; by Eastern Europe to its west; by Central Asia and East Asia to its south; and by the Pacific Ocean and Northern America to its east. It covers an area of 13,100,000 square kilometres (5,100,000 sq mi), or 8.8% of Earth's total land area; and is the largest subregion of Asia by area, occupying approx. 29.4% of Asia's land area, but is also the least populated, with a population of around 37 million, accounting for merely 0.74% of Asia's population.
Topographically, the region is dominated by the Eurasian Plate, except for its eastern part, which lies on the North American, Amurian, and Okhotsk Plates. It is divided by three major plains: the West Siberian Plain, Central Siberian Plateau, and Verhoyansk-Chukotka collision zone. The Uralian orogeny in the west raised Ural Mountains, the informal boundary between Asia and Europe. Tectonic and volcanic activities are frequently occurred in the eastern part of the region as part of the Ring of Fire, evidenced by the formation of island arcs such as the Kuril Islands and ultra-prominent peaks such as Klyuchevskaya Sopka, Kronotsky, and Koryaksky. The central part of North Asia is a large igneous province called the Siberian Traps, formed by a massive eruption which occurred 250 million years ago. The formation of the traps coincided with the Permian–Triassic extinction event.
Kurile Lake (Russian: Кури́льское о́зеро, romanized: Kuríl'skoye Ózero) is a caldera and crater lake in Kamchatka, Russia. It is also known as Kurilskoye Lake or Kuril Lake. It is part of the Eastern Volcanic Zone of Kamchatka which, together with the Sredinny Range, forms one of the volcanic belts of Kamchatka. These volcanoes form from the subduction of the Pacific Plate beneath the Okhotsk Plate and the Asian Plate.
Before the Kurile Lake caldera formed, the Pauzhetka caldera was active during the Pleistocene, and was the origin of the Golygin ignimbrite at 443,000 ± 8,000 years old. The Kurile Lake caldera erupted 41,500 years ago, and another small eruption occurred between 9,000 and 10,000 years ago; then in 6460–6414 BCE, a very large eruption took place, forming the present-day caldera and the Kurile Lake ignimbrite and depositing ash as far as 1,700 kilometres (1,100 mi) away. This eruption has a volume of 140–170 cubic kilometres (34–41 cu mi), making it a VEI-7-class eruption and one of the largest during the Holocene. Subsequently, the volcanoes Diky Greben and Ilinsky grew around the caldera; as of 2024, the most recent eruption from Ilinsky was in 1911. The caldera is filled by a lake with an area of 76 square kilometres (29 sq mi), and a maximum depth of 316 metres (1,037 ft). The largest sockeye salmon stocks in Asia live in the lake.