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Rift Zones
A rift zone is a feature of some volcanoes, especially shield volcanoes, in which a set of linear cracks (or rifts) develops in a volcanic edifice, typically forming into two or three well-defined regions along the flanks of the vent. Believed to be primarily caused by internal and gravitational stresses generated by magma emplacement within and across various regions of the volcano, rift zones allow the intrusion of magmatic dykes into the slopes of the volcano itself. The addition of these magmatic materials usually contributes to the further rifting of the slope, in addition to generating fissure eruptions from those dykes that reach the surface. It is the grouping of these fissures, and the dykes that feed them, that serves to delineate where and whether a rift zone is to be defined. The accumulated lava of repeated eruptions from rift zones along with the endogenous growth created by magma intrusions causes these volcanoes to have an elongated shape. Perhaps the best ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
East Rift Zone Kilauea
East or Orient is one of the four cardinal directions or points of the compass. It is the opposite direction from west and is the direction from which the Sun rises on the Earth. Etymology As in other languages, the word is formed from the fact that east is the direction where the Sun rises: ''east'' comes from Middle English ''est'', from Old English ''ēast'', which itself comes from the Proto-Germanic *''aus-to-'' or *''austra-'' "east, toward the sunrise", from Proto-Indo-European *aus- "to shine," or "dawn", cognate with Old High German ''*ōstar'' "to the east", Latin ''aurora'' 'dawn', and Greek ''ēōs'' 'dawn, east'. Examples of the same formation in other languages include Latin oriens 'east, sunrise' from orior 'to rise, to originate', Greek ανατολή anatolé 'east' from ἀνατέλλω 'to rise' and Hebrew מִזְרָח mizraḥ 'east' from זָרַח zaraḥ 'to rise, to shine'. '' Ēostre'', a Germanic goddess of dawn, might have been a personification ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monogenetic Volcanic Field
A monogenetic volcanic field is a type of volcanic field consisting of a group of small monogenetic volcanoes, each of which erupts only once, as opposed to polygenetic volcanoes, which erupt repeatedly over a period of time. The small monogenetic volcanoes of these fields are the most common subaerial volcanic landform. Many monogenetic volcanoes are cinder cones, often with lava flows, such as Parícutin in the Michoacán-Guanajuato volcanic field, which erupted from 1943 to 1952. Some monogenetic volcanoes are small lava shields, such as Rangitoto Island in the Auckland volcanic field. Other monogenetic volcanoes are tuff rings or maars. A monogenetic field typically contains between ten and a hundred volcanoes. The Michoacán-Guanajuato field in Mexico contains more than a thousand volcanoes and is exceptionally large. Monogenetic fields occur only where the magma supply to the volcano is low or where vents are not close enough or large enough to develop plumbing systems f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lateral Eruption
A lateral eruption or lateral blast is a volcanic eruption which is directed laterally from a volcano rather than upwards from the summit. Lateral eruptions are caused by the outward expansion of flanks due to rising magma. Breaking occurs at the flanks of volcanoes making it easier for magma to flow outward. As magma is pushed upward towards the volcano it diverges towards the flanks before it has a chance to erupt from the crater. When the expanding flank finally gives it releases a flow of magma. More explosive lateral eruptions are referred to as lateral blasts. Some of the most notable examples of a lateral eruption include Mount St. Helens, Mount Pelée, and Mount Etna. Creation of a lateral eruption Most eruptions are caused by the immediate decompression of a magma chamber near the flanks of the volcano. During an eruption, the rapid decompression of magma may cause subsidence of the mountain, and if a flank collapses, a lateral eruption occurs. The directed nature of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fracture (geology)
A fracture is any separation in a geologic formation, such as a joint or a fault that divides the rock into two or more pieces. A fracture will sometimes form a deep fissure or crevice in the rock. Fractures are commonly caused by stress exceeding the rock strength, causing the rock to lose cohesion along its weakest plane. Fractures can provide permeability for fluid movement, such as water or hydrocarbons. Highly fractured rocks can make good aquifers or hydrocarbon reservoirs, since they may possess both significant permeability and fracture porosity. Brittle deformation Fractures are forms of brittle deformation. There are two types of primary brittle deformation processes. Tensile fracturing results in ''joints''. ''Shear fractures'' are the first initial breaks resulting from shear forces exceeding the cohesive strength in that plane. After those two initial deformations, several other types of secondary brittle deformation can be observed, such as ''frictional s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Newberry Volcano
Newberry Volcano is a large active shield-shaped stratovolcano located about south of Bend, Oregon, United States, east of the major crest of the Cascade Range, within the Newberry National Volcanic Monument. Its highest point is Paulina Peak. The largest volcano in the Cascade Volcanic Arc, Newberry has an area of when its lava flows are taken into account. From north to south, the volcano has a length of , with a width of and a total volume of approximately . It was named for the geologist and surgeon John Strong Newberry, who explored central Oregon for the Pacific Railroad Surveys in 1855. The surrounding area has been inhabited by Native American populations for more than 10,000 years. The volcano contains a large caldera, in diameter, known as the Newberry Caldera. Within the caldera are two lakes: Paulina Lake and East Lake. The volcano and its vicinity include many pyroclastic cones, lava flows and lava domes; Newberry has more than 400 vents, the most of any vol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
El Hierro
El Hierro, nicknamed ''Isla del Meridiano'' (the "Meridian Island"), is the second-smallest and farthest-south and -west of the Canary Islands (an autonomous community of Spain), in the Atlantic Ocean off the coast of Africa, with a population of 10,968 (2019). Its capital is Valverde. At , it is the second-smallest of the eight main islands of the Canaries. Name The name ''El Hierro'', although spelled like the Spanish word for 'iron', is not related to that word. The ''H'' in the name of the metal is derived from the ''F'' of Latin ''ferrum'' (compare ''higo'' for 'fig'), a phonetic mutation that was complete by the end of the Middle Ages. The confusion with the name of the metal had effects on the international naming of the island. As early as the 16th century, maps and texts called the island after the word for 'iron' in other languages: Portuguese ''Ferro'', French ''l'île de Fer'', and Latin '' Insula Ferri''. Nevertheless, the origin of the name ''ero'' or ''er ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
La Palma
La Palma (, ), also known as ''La isla bonita'' () and officially San Miguel de La Palma, is the most north-westerly island of the Canary Islands, Spain. La Palma has an area of making it the fifth largest of the eight main Canary Islands. The total population at the end of 2020 was 85,840, of which 15,716 lived in the capital, Santa Cruz de La Palma and about 20,467 in Los Llanos de Aridane. Its highest mountain is the Roque de los Muchachos, at , being second among the peaks of the Canaries only to the peaks of the Teide massif on Tenerife. In 1815, the German geologist Leopold von Buch visited the Canary Islands. It was as a result of his visit to Tenerife, where he visited the Las Cañadas caldera, and then later to La Palma, where he visited the Taburiente caldera, that the Spanish word for cauldron or large cooking pot – "caldera" – was introduced into the geological vocabulary. In the center of the island is the Caldera de Taburiente National Park; one of four ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canary Islands
The Canary Islands (; es, Canarias, ), also known informally as the Canaries, are a Spanish autonomous community and archipelago in the Atlantic Ocean, in Macaronesia. At their closest point to the African mainland, they are west of Morocco. They are the southernmost of the autonomous communities of Spain. The islands have a population of 2.2 million people and they are the most populous special territory of the European Union. The seven main islands are (from largest to smallest in area) Tenerife, Fuerteventura, Gran Canaria, Lanzarote, La Palma, La Gomera, and El Hierro. The archipelago includes many smaller islands and islets, including La Graciosa, Alegranza, Isla de Lobos, Montaña Clara, Roque del Oeste, and Roque del Este. It also includes a number of rocks, including those of Salmor, Fasnia, Bonanza, Garachico, and Anaga. In ancient times, the island chain was often referred to as "the Fortunate Isles". The Canary Islands are the southernmost region of Spai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Māhukona
Māhukona is a submerged shield volcano on the northwestern flank of the Island of Hawaii. A drowned coral reef at about 3,770 feet (-1,150 m) below sea level and a major break in slope at about 4,400 feet (-1,340 m) below sea level represent old shorelines. A roughly circular caldera marks its summit. A prominent rift zone extends to the west. A second rift zone probably extended to the east but has been buried by younger volcanoes. The main shield-building stage of volcanism ended about 470,000 years ago. The summit of the shield volcano was once 800 feet (250 m) above sea level, but subsided below sea level between 435,000 and 365,000 years ago. Māhukona is the oldest volcano to build Hawaii island, older than Kohala and Mauna Kea. The Monterey Bay Aquarium Research Institute The Monterey Bay Aquarium Research Institute (MBARI) is a private, non-profit oceanographic research center in Moss Landing, California. MBARI was founded in 1987 by David Packard, and is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
