|
Lava Lakes
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''). Formation Lava lakes can form in three ways: *from one or more vents in a crater that erupts enough lava to partially fill the crater; or *when lava pours into a crater or broad depression and partially fills the crater; or *atop a new vent that erupts lava continuously for a period of several weeks or more and slowly builds a crater progressively higher than the surrounding ground. Behaviors Lava lakes occur in a variety of volcanic systems, ranging from the basaltic Erta Ale lake in Ethiopia and the basaltic andesite volcano of Villarrica, Chile, to the unique phonolitic lava lake at Mt. Erebus, Antarctica. Lava lakes have been observed to exhibit a range of behaviours. A "constantly circula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanic Crater Lake
A volcanic crater lake is a lake in a crater that was formed by explosive activity or a collapse during a volcanic eruption. Formation Lakes in calderas fill large craters formed by the collapse of a volcano during an eruption. Lakes in maars fill medium-sized craters where an eruption deposited debris around a vent. Crater lakes form as the created depression, within the crater rim, is filled by water. The water may come from precipitation, groundwater circulation (often hydrothermal fluids in the case of volcanic craters) or melted ice. Its level rises until an equilibrium is reached between the rates of incoming and outgoing water. Sources of water loss singly or together may include evaporation, subsurface seepage, and, in places, surface leakage or overflow when the lake level reaches the lowest point on its rim. At such a saddle location, the upper portion of the lake is contained only by its adjacent natural volcanic dam; continued leakage through or surface outflow ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kīlauea
Kīlauea ( , ) is an active shield volcano in the Hawaiian Islands. Located along the southeastern shore of the Big Island of Hawaii, the volcano is between 210,000 and 280,000 years old and emerged above sea level about 100,000 years ago. Historically, it is the most active of the five volcanoes that together form Hawaii island. Kīlauea is also one of the most active volcanoes on Earth, and the most recent and currently ongoing eruption began on September 29, 2021, when several vents began to erupt lava within Halemaʻumaʻu, a pit crater in the volcano's summit caldera. Kīlauea is the second-youngest product of the Hawaiian hotspot and the current eruptive center of the Hawaiian–Emperor seamount chain. Because it lacks topographic prominence and its activities historically coincided with those of Mauna Loa, Kīlauea was once thought to be a satellite of its much larger neighbor. Structurally, Kīlauea has a large, fairly recently formed caldera at its summit and two ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saunders Island, South Sandwich Islands
Saunders Island is a crescent-shaped island long, lying between Candlemas Island and Montagu Island in the South Georgia and the South Sandwich Islands, South Sandwich Islands, a British Overseas Territory in the southern Atlantic Ocean. It is a volcanic island composed of an active stratovolcano, Mount Michael. History Saunders Island was discovered in 1775 by Captain James Cook, who named it for Charles Saunders (admiral), Sir Charles Saunders, First Lord of the Admiralty. It was charted in greater detail by Fabian Gottlieb von Bellingshausen, Bellingshausen in 1819, and in 1930 by Discovery Investigations (DI) personnel aboard RRS Discovery II, ''Discovery II''. The island was surveyed in 1964 by . Polar explorer Ernest Shackleton sometimes misspells the island's name as "Sanders Island" in his book ''s:South: the story of Shackleton's last expedition, 1914-1917, South''. Features The centre of the island is Mount Michael, a volcano known to have erupted explosively in 1819 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
