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Surtseyan Eruption
A Surtseyan eruption is a type of explosive eruption that takes place in shallow seas or lakes when rapidly rising and fragmenting hot magma interacts explosively with water and with water-steam- tephra slurries. The eruption style is named after an eruption off the southern coast of Iceland in 1963 that caused the emergence of a new volcanic island, Surtsey. Surtseyan eruptions are phreatomagmatic (also known as ''hydromagmatic'') eruptions, in that they are violently explosive as a result of vigorous interaction between rising magma and lake or sea water. The magma is commonly basaltic and fragments into small pyroclasts (known as ' ash' and ' lapilli'), and these accumulate around the crater to form a small cone or ring-shaped heap. Volcanoes of this type are known as ' tuff cones' and ' tuff rings' because the volcanic ash of which they are made soon solidifies by chemical reaction into a hard rock known as ' tuff'. Surtseyan eruptions are characteristically unsteady, wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phreatomagmatic Eruption
Phreatomagmatic eruptions are volcanic eruptions resulting from interaction between magma and water. They differ from exclusively magmatic eruptions and phreatic eruptions. Unlike phreatic eruptions, the products of phreatomagmatic eruptions contain juvenile (magmatic) clasts.Heiken, G. & Wohletz, K. 1985. Volcanic Ash. University of California Press, Berkeley It is common for a large explosive eruption to have magmatic and phreatomagmatic components. Mechanisms Several competing theories exist as to the exact mechanism of ash formation. The most common is the theory of explosive thermal contraction of particles under rapid cooling from contact with water. In many cases the water is supplied by the sea, such as in the Surtsey eruption. In other cases the water may be present in a lake or caldera-lake, as at Santorini, where the phreatomagmatic component of the Minoan eruption was a result of both a lake and later the sea. There have also been examples of interaction between mag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sunda Strait
The Sunda Strait () is the strait between the Indonesian islands of Java island, Java and Sumatra. It connects the Java Sea with the Indian Ocean. Etymology The strait takes its name from the Sunda Kingdom, which ruled the western portion of Java (an area covering the present day West Java, Jakarta, Banten, and some of western Central Java) from 669 to around 1579."Sunda Islands". Concise Dictionary of World Place-Names. John Everett-Heath. Oxford University Press 2005. Oxford Reference Online. Oxford University Press. The name also alludes to the Sundanese people native to West Java and Banten. Geography Extending in a roughly southwest/northeast orientation, with a minimum width of at its northeastern end between Cape Tua on Sumatra and Cape Pujat on Java, the strait is part of the Java Sea. It is essentially triangular in shape, with two large bays on its northern side. It is also very broad and deep at its southwestern end, but as it narrows to the northeast it becomes mu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anak Krakatau
Anak KrakatauEnglish translation and common name: ''Child of Krakatoa'' is a volcanic island in Indonesia. On 29 December 1927, Anak Krakatau first emerged from the caldera formed in 1883 by the explosive volcanic eruption that destroyed the island of Krakatoa. There has been sporadic eruptive activity at the site since the late 20th century, culminating in a large sector collapse of the volcano, which caused a deadly tsunami in December 2018. There has been subsequent activity since. Owing to its young age the island is one of several in the area that are of interest to, and the subject of extensive study by volcanologists. History Background After the cataclysmic eruption of Krakatoa in 1883, Krakatoa Island lost approximately two-thirds of its mass on the northwest side, obliterating the peaks of Perboewatan and Danan, and leaving only the southern half of the island, including the Rakata volcano, as the last remnant of the original island. The lost area became a s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Italy
Italy, officially the Italian Republic, is a country in Southern Europe, Southern and Western Europe, Western Europe. It consists of Italian Peninsula, a peninsula that extends into the Mediterranean Sea, with the Alps on its northern land border, as well as List of islands of Italy, nearly 800 islands, notably Sicily and Sardinia. Italy shares land borders with France to the west; Switzerland and Austria to the north; Slovenia to the east; and the two enclaves of Vatican City and San Marino. It is the List of European countries by area, tenth-largest country in Europe by area, covering , and the third-most populous member state of the European Union, with nearly 59 million inhabitants. Italy's capital and List of cities in Italy, largest city is Rome; other major cities include Milan, Naples, Turin, Palermo, Bologna, Florence, Genoa, and Venice. The history of Italy goes back to numerous List of ancient peoples of Italy, Italic peoples—notably including the ancient Romans, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sicily
Sicily (Italian language, Italian and ), officially the Sicilian Region (), is an island in the central Mediterranean Sea, south of the Italian Peninsula in continental Europe and is one of the 20 regions of Italy, regions of Italy. With 4.7 million inhabitants, including 1.2 million in and around the capital city of Palermo, it is both the largest and most populous island in the Mediterranean Sea. Sicily is named after the Sicels, who inhabited the eastern part of the island during the Iron Age. Sicily has a rich and unique culture in #Art and architecture, arts, Music of Sicily, music, #Literature, literature, Sicilian cuisine, cuisine, and Sicilian Baroque, architecture. Its most prominent landmark is Mount Etna, the tallest active volcano in Europe, and one of the most active in the world, currently high. The island has a typical Mediterranean climate. It is separated from Calabria by the Strait of Messina. It is one of the five Regions of Italy#Autonomous regions with s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Graham Island (Mediterranean Sea)
Graham Island or Isola Ferdinandea (also ''Graham Bank'', ''Graham Shoal'', ) was an island in the Mediterranean Sea near Sicily that has, on more than one occasion, risen above the surface of the Mediterranean via volcanic action and soon thereafter been washed away. Since 300 BC this cycle of events has occurred four times. The island was part of the submarine volcano Empedocles (volcano), Empedocles, south of Sicily, which is one of a number of underwater volcanoes known as the Campi Flegrei del Mar di Sicilia. Seamount eruptions have raised the island above sea level several times before erosion submerged it again. The island's most recent "appearance" occurred in July 1831, but then by January 1832 the portion of the island above sea level had been entirely washed away again by the wind and the waves of the Mediterranean Sea. During the brief six-month lifespan of the island, a four-way dispute over the island's sovereignty arose, which was still unresolved when the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fire Island (Aleutian Islands)
Fire Island is located in the eastern Aleutian Islands at . It emerged in 1883, forming a companion island to Bogoslof Island. Originally, this Fire Island was named New Bogoslof (also Grewingk, after an Alaskan geologist). In 1909, President Theodore Roosevelt made Bogoslof and New Bogoslof a federally protected bird sanctuary A sanctuary, in its original meaning, is a sacred space, sacred place, such as a shrine, protected by ecclesiastical immunity. By the use of such places as a haven, by extension the term has come to be used for any place of safety. This seconda .... Both islands are currently part of the Bogoslof Wilderness in the Aleutian Islands unit of Alaska Maritime National Wildlife Refuge. References Islands of the Aleutian Islands Islands of Aleutians West Census Area, Alaska Islands of Alaska Islands of Unorganized Borough, Alaska {{AleutiansWestAK-geo-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alaska
Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the northernmost, westernmost, and easternmost (the Aleutian Islands cross the 180th meridian into the eastern hemisphere) state in the United States. It borders the Canadian territory of Yukon and the province of British Columbia to the east. It shares a western maritime border, in the Bering Strait, with Russia's Chukotka Autonomous Okrug. The Chukchi and Beaufort Seas of the Arctic Ocean lie to the north, and the Pacific Ocean lies to the south. Technically, it is a semi-exclave of the U.S., and is the largest exclave in the world. Alaska is the largest U.S. state by area, comprising more total area than the following three largest states of Texas, California, and Montana combined, and is the seventh-largest subnational division i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bogoslof Island
Bogoslof Island or Agasagook Island () is the summit of a submarine stratovolcano at the south edge of the Bering Sea, northwest of Unalaska Island of the Aleutian Islands chain. It has a land area of and is uninhabited. It is long and wide, with a peak elevation of . The stratovolcano rises about from the seabed, but the summit is the only part that projects above sea level. The island is believed to be relatively new, with the volcano being entirely below sea level before 1796, and most of the presently 300-acre island being formed by eruptions since 1900. History The first known emergence of the island above sea level was recorded during an underwater eruption in 1796. Since then, parts of the island have been successively added and eroded. About northwest of Bogoslof, a small volcanic dome emerged in 1883 from the same stratovolcano and has become a stack rock formation known as Fire Island (Aleutian Islands), Fire Island. On the southwest side of Bogoslof, another dome ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanic Bomb
A volcanic bomb or lava bomb is a mass of partially molten rock (tephra) larger than 64 mm (2.5 inches) in diameter, formed when a volcano ejects viscous fragments of lava during an eruption. Because volcanic bombs cool after they leave the volcano, they are extrusive igneous rocks. Volcanic bombs can be thrown many kilometres from an erupting vent, and often acquire aerodynamic shapes during their flight. Bombs can be extremely large; the 1935 eruption of Mount Asama in Japan expelled bombs measuring 5–6 m (16-20 ft) in diameter up to from the vent. Volcanic bombs are a significant volcanic hazard, and can cause severe injuries and death to people in an eruption zone. One such incident occurred at Galeras volcano in Colombia in 1993; six people near the summit were killed and several seriously injured by lava bombs when the volcano erupted unexpectedly. On July 16, 2018, 23 people were injured on a tour boat near the Kilauea volcano as a result of a baske ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lava
Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a Natural satellite, moon onto its surface. Lava may be erupted at a volcano or through a Fissure vent, fracture in the Crust (geology), crust, on land or underwater, usually at temperatures from . The volcanic rock resulting from subsequent cooling is often also called ''lava''. A lava flow is an outpouring of lava during an effusive eruption. (An explosive eruption, by contrast, produces a mixture of volcanic ash and other fragments called tephra, not lava flows.) The viscosity of most lava is about that of ketchup, roughly 10,000 to 100,000 times that of water. Even so, lava can flow great distances before cooling causes it to solidify, because lava exposed to air quickly develops a solid crust that insulates the remaining liquid lava, helping to keep it hot and inviscid enough to continue flowing. Etymology The word ''lava'' comes from Ital ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
