|
Parasitic Cone
A parasitic cone (also adventive cone, satellite cone, satellitic cone or lateral cone) is the cone-shaped accumulation of volcanic material not part of the central vent of a volcano. It forms from eruptions from fractures on the flank of the volcano. These fractures occur because the flank of the volcano is unstable. Eventually, the fractures reach the magma chamber and generate eruptions called flank eruptions, which, in turn, produce a parasitic cone. A parasitic cone can also be formed from a dike or sill cutting up to the surface from the central magma chamber in an area different from the central vent. A peculiar example of multiple parasitic cones is Jeju Island in South Korea. Jeju Island features 368 " oreums" (Korean: ; "mount"), which lie in a roughly lateral line on either side of the island's central dormant shield volcano Hallasan. See also * Volcanic crater A volcanic crater is an approximately circular depression in the ground caused by volcanic activ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcano
A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates are diverging or converging, and because most of Earth's plate boundaries are underwater, most volcanoes are found underwater. For example, a mid-ocean ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates. Volcanoes resulting from divergent tectonic activity are usually non-explosive whereas those resulting from convergent tectonic activity cause violent eruptions."Mid-ocean ridge tectonics, volcanism and geomorphology." Geology 26, no. 455 (2001): 458. https://macdonald.faculty.geol.ucsb.edu/papers/Macdonald%20Mid-Ocean%20Ridge%20Tectonics.pdf Volcanoes can also form where there is str ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magma Chamber
A magma chamber is a large pool of liquid rock beneath the surface of the Earth. The molten rock, or magma, in such a chamber is less dense than the surrounding country rock, which produces buoyant forces on the magma that tend to drive it upwards. If the magma finds a path to the surface, then the result will be a volcanic eruption; consequently, many volcanoes are situated over magma chambers. These chambers are hard to detect deep within the Earth, and therefore most of those known are close to the surface, commonly between 1 km and 10 km down. Dynamics of magma chambers Magma rises through cracks from beneath and across the crust because it is less dense than the surrounding rock. When the magma cannot find a path upwards it pools into a magma chamber. These chambers are commonly built up over time, by successive horizontal or vertical magma injections. The influx of new magma causes reaction of pre-existing crystals and the pressure in the chamber to increa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flank Eruption
Flank may refer to: * Flank (anatomy), part of the abdomen ** Flank steak, a cut of beef ** Part of the external anatomy of a horse * Flank speed, a nautical term * Flank opening, a chess opening * A term in Australian rules football * The side of a military unit, as in a flanking maneuver * Flanking, a sound path in architectural acoustics * Flanking region, a region of DNA in directionality * Rift flank (synonymous of rift shoulder In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics. Typical rift features are a central linear downfaulted depression, called a graben, or more commonly a half-graben ...), mountains belt on the sides of extensional rift basins See also * Flanker (other) {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
San Diego State University
San Diego State University (SDSU) is a Public university, public research university in San Diego, California, United States. Founded in 1897, it is the third-oldest university and southernmost in the 23-member California State University (CSU) system. SDSU is the oldest higher education institution in San Diego; its academic roots were established as a normal school in University Heights, San Diego, University Heights, then known as the San Diego Normal School. In the fall of 2024, the university enrolled over 38,000 students. SDSU comprises eight colleges and offers over 200 degree programs at the undergraduate and graduate levels. It is Higher education accreditation in the United States, accredited by the Western Association of Schools and Colleges#WASC Senior College and University Commission, WASC Senior College and University Commission (WSCUC). The university is Carnegie Classification of Institutions of Higher Education, classified among "R1: Doctoral Universities – ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dike (geology)
In geology, a dike or dyke is a sheet of rock that is formed in a fracture of a pre-existing rock body. Dikes can be either magmatic or sedimentary in origin. Magmatic dikes form when magma flows into a crack then solidifies as a sheet intrusion, either cutting across layers of rock or through a contiguous mass of rock. Clastic dikes are formed when sediment fills a pre-existing crack.Essentials of Geology, 3rd Ed, Stephen Marshak Magmatic dikes A magmatic dike is a sheet of igneous rock that cuts across older rock beds. It is formed when magma fills a fracture in the older beds and then cools and solidifies. The dike rock is usually more resistant to weathering than the surrounding rock, so that erosion exposes the dike as a natural wall or ridge. It is from these natural walls that dikes get their name. Dikes preserve a record of the fissures through which most mafic magma (fluid magma low in silica) reaches the surface. They are studied by geologists for the clues they ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sill (geology)
In geology, a sill is a tabular sheet intrusion that has intruded between older layers of sedimentary rock, beds of volcanic lava or tuff, or along the direction of foliation in metamorphic rock. A sill is a ''concordant intrusive sheet'', meaning that it does not cut across preexisting rock beds. Stacking of sills builds a sill complex. and a large magma chamber at high magma flux. In contrast, a dike is a discordant intrusive sheet, which does cut across older rocks. Formation Sills are fed by dikes, except in unusual locations where they form in nearly vertical beds attached directly to a magma source. The rocks must be brittle and fracture to create the planes along which the magma intrudes the parent rock bodies, whether this occurs along preexisting planes between sedimentary or volcanic beds or weakened planes related to foliation in metamorphic rock. These planes or weakened areas allow the intrusion of a thin sheet-like body of magma paralleling the existi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jeju Island
Jeju Island (Jeju language, Jeju/) is South Korea's largest island, covering an area of , which is 1.83% of the total area of the country. Alongside outlying islands, it is part of Jeju Province and makes up the majority of the province. The island lies in the Korea Strait, south of the nearest point on the Korean Peninsula. The Jeju people are indigenous to the island, and it has been populated by modern humans since the early Neolithic, Neolithic period. The Jeju language is considered critically endangered by UNESCO. It is also one of the regions of Korea where Korean shamanism, Shamanism is most intact. Jeju Island has an oval shape and is east–west and north–south, with a gentle slope around Hallasan in the center. The length of the main road is and the coastline is . On the northern end of Jeju Island is Gimnyeong Beach, on the southern end Songaksan (Jeju), Songak Mountain, the western end Suwolsan, Suwol Peak, and the eastern end Seongsan Ilchulbong. The island ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oreum
''Oreum'' () refers to the around 360 small rising extinct volcanoes on Jeju Island, in Jeju Province, South Korea. They are commonly described as cinder cones or parasitic cones, and are often inside larger volcanic craters. Etymology The word ''oreum'' comes from the Jeju language. It refers to small mountains. "Oreum" itself originates from the word "climb" (). The word is now considered to refer to Jeju's numerous small parasitic cones (; also ). Description Around 360 ''oreum'' are distributed throughout Jeju. Their formation and preservation are due in part to the high permeability (earth sciences), permeability of the volcanic rock. Magma erupting under pressure can solidify into scoria, which may fall and pile up around a crater to form circular and elliptical scoria cones and cinder cones. These are popularly known as ''oreum'' in Jeju Island. There are about 360 such ''oreum''. ''Oreum'' are classified as cinder cones, lava domes, fault blocks, or cryptodomes. ''O ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Korean Language
Korean is the first language, native language for about 81 million people, mostly of Koreans, Korean descent. It is the national language of both South Korea and North Korea. In the south, the language is known as () and in the north, it is known as (). Since the turn of the 21st century, aspects of Korean Wave, Korean popular culture have spread around the world through globalization and Korean Wave, cultural exports. Beyond Korea, the language is recognized as a minority language in parts of China, namely Jilin, and specifically Yanbian Korean Autonomous Prefecture, Yanbian Prefecture, and Changbai Korean Autonomous County, Changbai County. It is also spoken by Sakhalin Koreans in parts of Sakhalin, the Russian island just north of Japan, and by the in parts of Central Asia. The language has a few Extinct language, extinct relatives which—along with the Jeju language (Jejuan) of Jeju Island and Korean itself—form the compact Koreanic language family. Even so, Jejuan and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shield Volcano
A shield volcano is a type of volcano named for its low profile, resembling a shield lying on the ground. It is formed by the eruption of highly fluid (low viscosity) lava, which travels farther and forms thinner flows than the more viscous lava erupted from a stratovolcano. Repeated eruptions result in the steady accumulation of broad sheets of lava, building up the shield volcano's distinctive form. Shield volcanoes are found wherever fluid, low-silica lava reaches the surface of a rocky planet. However, they are most characteristic of ocean Volcanic island, island volcanism associated with Hotspot (geology), hot spots or with Rift, continental rift volcanism. They include the largest active volcanoes on Earth, such as Mauna Loa. Giant shield volcanoes are found on other planets of the Solar System, including Olympus Mons on Mars and Sapas Mons on Venus. Etymology The term 'shield volcano' is taken from the German term ''Schildvulkan'', coined by the Austrian geologist Eduar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hallasan
Hallasan () is a shield volcano comprising much of Jeju Island in South Korea. Its summit, at , is the highest point in the country. The area around the mountain is a designated national park, named Hallasan National Park. Hallasan is commonly considered to be one of the three main mountains of South Korea, along with Jirisan and Seoraksan. The Hallasan Natural Reserve was designated as a South Korean Natural Monument number 182 on October 12, 1966. Names Alternate English names for the mountain include ''Hanla Mountain'' and ''Mount Halla'', and older English sources refer to the peak as ''Mount Auckland''. Hallasan is written in Hangul as if it were ''Hanrasan'' (), but is still pronounced ''Hallasan''. In the past, Hallasan has been known by numerous other names in Korean including ''Buak'' (), ''Wonsan'' (), ''Jinsan'' (), ''Seonsan'' (), ''Dumuak'' (), ''Burasan'' (), ''Yeongjusan'' (), and ''Hyeolmangbong'' (). Geology and geography Hallasan Hallasan is a massive s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
