Kamchatka Peninsula in the context of "Sea of Okhotsk"

The Kuril Islands or Kurile Islands are a volcanic archipelago administered as part of Sakhalin Oblast in the Russian Far East. The islands stretch approximately 1,300 km (810 mi) northeast from Hokkaido in Japan to Kamchatka Peninsula in Russia, separating the Sea of Okhotsk from the north Pacific Ocean. There are 56 islands and many minor islets. The Kuril Islands consist of the Greater Kuril Chain and, at the southwest end, the parallel Lesser Kuril Chain. The group termed the 'South Kurils' consists of those of the Lesser Kuril Chain together with Kunashir and Iturup in the Greater Kuril Chain. The Vries Strait between Iturup and Urup forms the Miyabe Line dividing the North and South Kurils. The Kuril Islands cover an area of around 10,503.2 square kilometres (4,055.3 sq mi), with a population of roughly 20,000.

The islands have been under Russian administration since their 1945 invasion by the Soviet Union near the end of World War II. Japan claims the four southernmost islands, including two of the three largest (Iturup and Kunashir), as part of its territory, as well as Shikotan and the unpopulated Habomai islets, which has led to the ongoing Kuril Islands dispute. The disputed islands are known in Japan as the country's "Northern Territories".

Pumice ( /ˈpʌmɪs/), called pumicite in its powdered or dust form, is a volcanic rock that consists of extremely vesicular rough-textured volcanic glass, which may or may not contain crystals. It is typically light-colored. Scoria is another vesicular volcanic rock that differs from pumice in having larger vesicles, thicker vesicle walls, and being dark colored and denser.

Pumice is created when super-heated, highly pressurized rock is rapidly ejected from a volcano. The unusual foamy configuration of pumice happens because of simultaneous rapid cooling and rapid depressurization. The depressurization creates bubbles by lowering the solubility of gases (including water and CO₂) that are dissolved in the lava, causing the gases to rapidly exsolve (like the bubbles of CO₂ that appear when a carbonated drink is opened). The simultaneous cooling and depressurization freeze the bubbles in a matrix. Pumice is fragments of lava or tephra that cooled in air or water. If pumice from an underwater volcanic eruption reaches the water surface, it can form pumice rafts on the water surface that can be a hazard for ships.

Beringia is a prehistoric geographical region, defined as the land and maritime area bounded on the west by the Lena River in Russia; on the east by the Mackenzie River in Canada; on the north by 72° north latitude in the Chukchi Sea; and on the south by the tip of the Kamchatka Peninsula. It includes the Chukchi Sea, the Bering Sea, the Bering Strait, the Chukchi and Kamchatka peninsulas in Russia as well as Alaska in the United States and Yukon in Canada.

The area includes land lying on the North American Plate and Siberian land east of the Chersky Range. At various times, it formed a land bridge referred to as the Bering land bridge or the Bering Strait land bridge that was up to 1,000 km (620 mi) wide at its greatest extent and which covered an area as large as British Columbia and Alberta together, totaling about 1.6 million km (620,000 sq mi), allowing biological dispersal to occur between Asia and North America. Today, the only land that is visible from the central part of the Bering land bridge are the Diomede Islands, the Pribilof Islands of St. Paul and St. George, St. Lawrence Island, St. Matthew Island, and King Island.

The Ainu languages (/ˈaɪnuː/ EYE-noo), sometimes known as Ainuic, were a small language family, often regarded as a language family isolate, historically spoken by the Ainu people of northern Japan and neighboring islands, up to the southern tip of the Kamchatka Peninsula.

The primary varieties of Ainu are alternately considered a group of closely related languages or divergent dialects of a single language isolate. Toponymic evidence suggests Ainu was once spoken in northern Honshu and that much of the historically attested extent of the family was due to a relatively recent expansion northward. No genealogical relationship between Ainu and any other language family has been demonstrated, despite numerous attempts.

Ainu (アイヌ イタㇰ, aynu itak), or more precisely Hokkaido Ainu (Japanese: 北海道アイヌ語), is the native language of the Ainu people on the northern Japanese island of Hokkaido. It is a member of the Ainu language family, itself considered a language family isolate with no academic consensus regarding its origin. Until the 20th century, the Ainu languages – Hokkaido Ainu, Kuril Ainu, and Sakhalin Ainu – were spoken throughout Hokkaido, the southern half of the island of Sakhalin and by small communities in the Kuril Islands, up to the southern tip of Kamchatka.

Following the colonization of Hokkaido, the number of Hokkaido Ainu speakers declined steadily throughout the 20th century. By 2008, Hokkaido Ainu was critically endangered, with only two elderly people reported to speak it as their first language. According to the linguist Hiroshi Nakagawa, by 2021 no one in Japan had Ainu as their first language.

44°6′N 146°42′E / 44.100°N 146.700°E / 44.100; 146.700

Japan and Russia have a territorial dispute over the four southernmost Kuril Islands. The Kuril Islands are a chain of islands that stretch between the Japanese island of Hokkaido at their southern end and the Russian Kamchatka Peninsula at their northern end. The islands separate the Sea of Okhotsk from the Pacific Ocean. The four disputed islands, like other islands in the Kuril chain which are not in dispute, were unilaterally annexed by the Soviet Union following the Invasion of the Kuril Islands at the end of World War II. The disputed islands are under Russian administration as the South Kuril District and part of the Kuril District of the Sakhalin Oblast (Сахалинская область, Sakhalinskaya oblast). They are claimed by Japan, which refers to them as its Northern Territories or Southern Chishima, and considers them part of the Nemuro Subprefecture of Hokkaido Prefecture.

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.

Kronotsky (Russian: Кроноцкая сопка, Kronotskaya Sopka) is a major stratovolcano on the Kamchatka Peninsula, Russia. It is located in Kronotsky Nature Reserve to the east of Lake Kronotskoye (the largest freshwater lake in Kamchatka). It has a particularly symmetrical conical shape, comparable to Mount Fuji in Japan and to Mayon Volcano in the Philippines. The summit crater is plugged by a volcanic neck, and the summit itself is ice-capped. It exhibits the classic radial drainage pattern, extending downward from its crater. Kronotsky is considered to be one of the most scenic volcanoes in Kamchatka. In the 20th century, the volcano had low activity, with occasional weak phreatic eruptions. Its latest eruption started on October 4, 2025, with an ash cloud up to 9 km (5.6 mi) high.