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Axial Seamount
Axial Seamount (also Coaxial Seamount or Axial Volcano) is a seamount and submarine volcano in the Pacific Ocean, located on the Juan de Fuca Ridge, approximately west of Cannon Beach, Oregon. Standing high, Axial Seamount is the youngest volcano and current eruptive center of the Cobb–Eickelberg Seamount chain. Located at the center of both a geological hotspot and a mid-ocean ridge, the seamount is geologically complex, and its origins are still poorly understood. Axial Seamount is set on a long, low-lying plateau, with two large rift zones trending to the northeast and southwest of its center. The volcano features an unusual rectangular caldera, and its flanks are pockmarked by fissures, vents, sheet flows, and pit craters up to deep; its geology is further complicated by its intersection with several smaller seamounts surrounding it. Axial Seamount was first detected in the 1970s by satellite altimetry, and mapped and explored by ''Pisces IV'', ''DSV Alvin'', and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Oceanic And Atmospheric Administration
The National Oceanic and Atmospheric Administration (abbreviated as NOAA ) is an United States scientific and regulatory agency within the United States Department of Commerce that forecasts weather, monitors oceanic and atmospheric conditions, charts the seas, conducts deep sea exploration, and manages fishing and protection of marine mammals and endangered species in the U.S. exclusive economic zone. Purpose and function NOAA's specific roles include: * ''Supplying Environmental Information Products''. NOAA supplies to its customers and partners information pertaining to the state of the oceans and the atmosphere, such as weather warnings and forecasts via the National Weather Service. NOAA's information services extend as well to climate, ecosystems, and commerce. * ''Providing Environmental Stewardship Services''. NOAA is a steward of U.S. coastal and marine environments. In coordination with federal, state, local, tribal and international authorities, NOAA manages the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caldera
A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcano eruption. When large volumes of magma are erupted over a short time, structural support for the rock above the magma chamber is gone. The ground surface then collapses into the emptied or partially emptied magma chamber, leaving a large depression at the surface (from one to dozens of kilometers in diameter). Although sometimes described as a crater, the feature is actually a type of sinkhole, as it is formed through subsidence and collapse rather than an explosion or impact. Compared to the thousands of volcanic eruptions that occur each century, the formation of a caldera is a rare event, occurring only a few times per century. Only seven caldera-forming collapses are known to have occurred between 1911 and 2016. More recently, a caldera collapse occurred at Kīlauea, Hawaii in 2018. Etymology The term ''caldera'' comes from Spanish ', and Latin ', mean ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spreading Center
A mid-ocean ridge (MOR) is a seafloor mountain system formed by plate tectonics. It typically has a depth of about and rises about above the deepest portion of an ocean basin. This feature is where seafloor spreading takes place along a divergent plate boundary. The rate of seafloor spreading determines the morphology of the crest of the mid-ocean ridge and its width in an ocean basin. The production of new seafloor and oceanic lithosphere results from mantle upwelling in response to plate separation. The melt rises as magma at the linear weakness between the separating plates, and emerges as lava, creating new oceanic crust and lithosphere upon cooling. The first discovered mid-ocean ridge was the Mid-Atlantic Ridge, which is a spreading center that bisects the North and South Atlantic basins; hence the origin of the name 'mid-ocean ridge'. Most oceanic spreading centers are not in the middle of their hosting ocean basis but regardless, are traditionally called mid-ocean r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cobb Hotspot
The Cobb hotspot is a marine volcanic hotspot at (46˚ N, 130˚ W), which is 460 km (290 mi) west of Oregon and Washington, North America, in the Pacific Ocean. Over geologic time, the Earth's surface has migrated with respect to the hotspot through plate tectonics, creating the Cobb–Eickelberg Seamount chain. The hotspot is currently collocated with the Juan de Fuca Ridge. Cobb Seamount chain The Cobb hotspot has created an underwater mountain range that extends to the northwest and ends at the Aleutian Trench. The oldest mount in the chain is the Marchland Seamount, at 30 to 43 Ma (million years old). The old, northwestern end of the chain collides with a subduction zone; therefore, the true age of the hotspot is difficult to determine as the oceanic crust is being consumed. Axial Seamount is the hotspot's most recent eruptive center, which last erupted in 2015, 2011 and 1998. The central ridge of the hotspot is thicker than the surrounding crust by a few k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lava Flow
Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or underwater, usually at temperatures from . The volcanic rock resulting from subsequent cooling is also often 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. The word ''lava'' comes from Italian and is probably derived from the Latin word ''labes' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
In Situ
''In situ'' (; often not italicized in English) is a Latin phrase that translates literally to "on site" or "in position." It can mean "locally", "on site", "on the premises", or "in place" to describe where an event takes place and is used in many different contexts. For example, in fields such as physics, geology, chemistry, or biology, ''in situ'' may describe the way a measurement is taken, that is, in the same place the phenomenon is occurring without isolating it from other systems or altering the original conditions of the test. The opposite of ''in situ'' is ''ex situ''. Aerospace In the aerospace industry, equipment on-board aircraft must be tested ''in situ'', or in place, to confirm everything functions properly as a system. Individually, each piece may work but interference from nearby equipment may create unanticipated problems. Special test equipment is available for this ''in situ'' testing. It can also refer to repairs made to the aircraft structure or flight ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Submarine Eruption
Submarine eruptions are those volcano eruptions which take place beneath the surface of water. These occur at constructive margins, subduction zones and within tectonic plates due to hotspots. This eruption style is far more prevalent than subaerial activity. For example, it is believed that 70 to 80% of the Earth's magma output takes place at mid-ocean ridges.Parfitt, L. and Wilson, L. (2008) ''Fundamentals of Physical Volcanology'', Blackwell Publishing. Detection Submarine eruptions are less studied than subaerial volcanoes due to their inaccessibility. Developments in technology mean that submarine volcanoes can now be studied in greater detail. Despite this progress, understanding is still limited. Mid ocean ridges for example are the most active volcanic systems on Earth but roughly only 5% of their length has been studied in detail.Fagents, S.A., Gregg, T.K.P. and Lopes, R.M.C. (2013) ''Modelling Volcanic processes: the Physics and Mathematics of Volcanism'', Cambridge Un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DSV Alvin
''Alvin'' (DSV-2) is a crewed deep-ocean research submersible owned by the United States Navy and operated by the Woods Hole Oceanographic Institution (WHOI) in Woods Hole, Massachusetts. The vehicle was built by General Mills' Electronics Group in Minneapolis, Minnesota. Named to honor the prime mover and creative inspiration for the vehicle, Allyn Vine, ''Alvin'' was commissioned on 5 June 1964. The submersible is launched from the deep submergence support vessel , which is also owned by the U.S. Navy and operated by WHOI. The submersible has made more than 5,000 dives, carrying two scientists and a pilot, to observe the lifeforms that must cope with super-pressures and move about in total darkness, as well as exploring the wreck of ''Titanic''. Research conducted by ''Alvin'' has been featured in nearly 2,000 scientific papers. Design ''Alvin'' was designed as a replacement for bathyscaphes and other less maneuverable oceanographic vehicles. Its more nimble design was made ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pisces IV
''Pisces IV'' is a three-person, battery-powered deep-submergence vehicle (or DSV), with a maximum operating depth of . The craft was built by Hyco International Hydrodynamics in Vancouver, and is currently owned by the Hawaii Undersea Research Laboratory arm of the National Oceanic and Atmospheric Administration. It and its sister, '' Pisces V'', are Pisces class submersibles used by the NOAA for oceanic exploration. ''Pisces IV'' was constructed in 1973 and immediately placed in the service of the Department of Fisheries and Oceans of Canada. The DSV was used by the Institute of Ocean Sciences and operated at different times in the Atlantic, Arctic, and Pacific oceans. After over 1886 dives, budget cuts forced the cancellation of support for the project. ''Pisces IV'' has since been replaced in that role by ''ROPOS''. More recently, after transfer to the US, ''Pisces IV'' was certified for use by the American Bureau of Shipping in 2000, and underwent modernization and upgra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Satellite Altimetry
Satellite geodesy is geodesy by means of artificial satellites—the measurement of the form and dimensions of Earth, the location of objects on its surface and the figure of the Earth's gravity field by means of artificial satellite techniques. It belongs to the broader field of space geodesy. Traditional astronomical geodesy is ''not'' commonly considered a part of satellite geodesy, although there is considerable overlap between the techniques. The main goals of satellite geodesy are: # Determination of the figure of the Earth, positioning, and navigation (geometric satellite geodesy) # Determination of geoid, Earth's gravity field and its temporal variations (dynamical satellite geodesy or satellite physical geodesy) # Measurement of geodynamical phenomena, such as crustal dynamics and polar motion Satellite geodetic data and methods can be applied to diverse fields such as navigation, hydrography, oceanography and geophysics. Satellite geodesy relies heavily on or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pit Crater
A pit crater (also called a subsidence crater or collapse crater) is a depression formed by a sinking or collapse of the surface lying above a void or empty chamber, rather than by the eruption of a volcano or lava vent. Pit craters are found on Mercury, Venus, Earth, Mars, and the Moon. Pit craters are often found in a series of aligned or offset chains and in these cases, the features is called a pit crater chain. Pit crater chains are distinguished from catenae or crater chains by their origin. When adjoining walls between pits in a pit crater chain collapse, they become troughs. In these cases, the craters may merge into a linear alignment and are commonly found along extensional structures such as fractures, fissures and graben. Pit craters usually lack an elevated rim as well as the ejecta deposits and lava flows that are associated with impact craters.Okubo, Chris, and Stephen Martel. "Pit crater formation on Kilauea volcano, Hawaii." Journal of Volcanology and Geothe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
