Lava lakes are large volumes of molten lava, usually basaltic, contained in a volcanic vent, crater, or broad depression. The term is used to describe both lava lakes that are wholly or partly molten and those that are solidified (sometimes referred to as frozen lava lakes).
Saunders Island is a crescent-shaped island lying between Candlemas Island and Montagu Island in the South Sandwich Islands, a British Overseas Territory in the southern Atlantic Ocean.
The 8.5 by 5 kilometres (5.3 mi × 3.1 mi) long Saunders is a volcanic island composed of an active stratovolcano, 990-metre (3,248 ft) Mount Michael, and a cluster of pyroclastic cones on the southeastern side. Mount Michael has a lava lake in its summit crater, which is fumarolically active, and there is widespread evidence of recent eruptions across the island.
A volcanogenic lake is a lake formed as a result of volcanic activity. They are generally a body of water inside an inactive volcanic crater (crater lakes) but can also be large volumes of molten lava within an active volcanic crater (lava lakes) and waterbodies constrained by lava flows, pyroclastic flows or lahars in valley systems. The term volcanic lake is also used to describe volcanogenic lakes, although it is more commonly assigned to those inside volcanic craters.
A Hawaiian eruption is a type of volcanic eruption where lava flows from the vent in a relatively gentle, low level eruption; it is so named because it is characteristic of Hawaiian volcanoes. Typically they are effusive eruptions, with basaltic magmas of low viscosity, low content of gases, and high temperature at the vent. Very small amounts of volcanic ash are produced. This type of eruption occurs most often at hotspot volcanoes such as Kīlauea on Hawaii's big island and in Iceland, though it can occur near subduction zones (e.g. Medicine Lake Volcano in California) and rift zones. Hawaiian eruptions may occur along fissure vents, such as during the eruption of Mauna Loa in 1950, or at a central vent, such as during the 1959 eruption in Kīlauea Iki Crater, which created a lava fountain 580 meters (1,900 ft) high and formed a 38-meter cone named Puʻu Puaʻi. In fissure-type eruptions, lava spurts from a fissure on the volcano's rift zone and feeds lava streams that flow downslope. In central-vent eruptions, a fountain of lava can spurt to a height of 300 meters or more (heights of 1600 meters were reported for the 1986 eruption of Mount Mihara on Izu Ōshima, Japan).
Hawaiian eruptions usually start from an increase earthquake activity in a localized region followed with the formation of cracks in the ground from which a curtain of incandescent lava or several closely spaced lava fountains appear. The lava can overflow the fissure and form ʻaʻā or pāhoehoe style of flows. When such an eruption from a central cone is protracted, it can form lightly sloped shield volcanoes, for example Mauna Loa or Skjaldbreiður in Iceland. Geologists can predict where new eruptions will take place by tracking the earthquakes that precede the eruptions.
Mount Nyiragongo (/ˌnɪərəˈɡɒŋɡoʊ, -ˈɡɔːŋ-/ neer-ə-GONG-go) is an active stratovolcano with an elevation of 3,470 m (11,385 ft) in the Virunga Mountains associated with the Albertine Rift. It is located inside Virunga National Park, in the Democratic Republic of the Congo, about 12 km (7.5 mi) north of the town of Goma and Lake Kivu and just west of the border with Rwanda. The main crater is about two kilometres (1 mi) wide and usually contains a lava lake. The crater presently has two distinct cooled lava benches within the crater walls – one at about 3,175 m (10,417 ft) and a lower one at about 2,975 m (9,760 ft).
Nyiragongo's lava lake has at times been the most voluminous known lava lake in most recent history. The depth of the lava lake varies considerably. A maximum elevation of the lava lake was recorded at about 3,250 m (10,660 ft) prior to the January 1977 eruption – a lake depth of about 600 m (2,000 ft). Following the January 2002 eruption, the lava lake was recorded at a low of about 2,600 m (8,500 ft), or 900 m (3,000 ft) below the rim. The level has gradually risen since then. Nyiragongo and nearby Nyamuragira are together responsible for 40% of Africa's historical volcanic eruptions.
A volcanic landslide or volcanogenic landslide is a type of mass wasting that takes place at volcanoes.