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Lava Coil
A lava coil is a spiral or scroll-shaped lava formation occurring when relatively low viscosity lava such as Pahoehoe solidifies along a slow-moving shear zone in the flow. The shear produces a Kelvin–Helmholtz instability that forms spiral-shaped patterns. Depending on the side of the flow the spiral is clockwise or anti-clockwise. They have been observed on flows near Kilauea on Hawai'i, in KenyaTemperley BN (1966) Vortex exudation coils on a recent basaltic lava in Kenya. Overseas Geol Mineral. Resour. 10:42-46 and possibly on Mars. File:lava coil.png, Surface of December 31, 1974 pahoehoe northeast of Pu‘u Koa ́e, Hawaii. Lava coil is 10 m diameter. File:Weird-Lava-flows-on-Mars.jpg, Spirals interpreted to be lava coils on the surface of a Martian lava lake in Cerberus Palus Cerberus Palus is a plain in the Elysium quadrangle of Mars, centered at . It is 470 km across and was named after a classical albedo feature Cerberus. Cerberus Palus once contained a la ... [...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 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] |
Pahoehoe
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'', w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shear (fluid)
Shear stress, often denoted by (Greek: tau), is the component of stress coplanar with a material cross section. It arises from the shear force, the component of force vector parallel to the material cross section. ''Normal stress'', on the other hand, arises from the force vector component perpendicular to the material cross section on which it acts. General shear stress The formula to calculate average shear stress is force per unit area.: : \tau = , where: : = the shear stress; : = the force applied; : = the cross-sectional area of material with area parallel to the applied force vector. Other forms Wall shear stress Wall shear stress expresses the retarding force (per unit area) from a wall in the layers of a fluid flowing next to the wall. It is defined as: \tau_w:=\mu\left(\frac\right)_ Where \mu is the dynamic viscosity, u the flow velocity and y the distance from the wall. It is used, for example, in the description of arterial blood flow in which case which there ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kelvin–Helmholtz Instability
The Kelvin–Helmholtz instability (after Lord Kelvin and Hermann von Helmholtz) is a fluid instability that occurs when there is velocity shear in a single continuous fluid or a velocity difference across the interface between two fluids. Kelvin-Helmholtz instabilities are visible in the atmospheres of planets and moons, such as in cloud formations on Earth or the Red Spot on Jupiter, and the atmospheres of the Sun and other stars. Theory overview and mathematical concepts Fluid dynamics predicts the onset of instability and transition to turbulent flow within fluids of different densities moving at different speeds. If surface tension is ignored, two fluids in parallel motion with different velocities and densities yield an interface that is unstable to short-wavelength perturbations for all speeds. However, surface tension is able to stabilize the short wavelength instability up to a threshold velocity. If the density and velocity vary continuously in space (wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hawaii (island)
Hawaii ( ; haw, Hawaii ) is the List of islands of the United States by area, largest island in the United States, located in the U.S. state, state of Hawaii. It is the southeasternmost of the Hawaiian Islands, a chain of High island, volcanic islands in the Pacific Ocean, North Pacific Ocean. With an area of , it has 63% of the Hawaiian archipelago's combined landmass. However, it has only 13% of Hawaiʻi's population. The island of Hawaiʻi is the third largest island in Polynesia, behind the two main List of islands of New Zealand, islands of New Zealand. The island is often referred to as the Island of Hawaii or Hawaii Island to distinguish it from the state. It is also referred to as the Big Island. Administratively, the island is coextensive with Hawaii County, Hawaii, Hawaii County. As of the 2020 United States census, 2020 census, the population was 200,629. The county seat and largest town is Hilo, Hawaii, Hilo. There are no Municipal corporation, incorporated cities i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pahoehoe
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'', w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cerberus Palus
Cerberus Palus is a plain in the Elysium quadrangle of Mars, centered at . It is 470 km across and was named after a classical albedo feature Cerberus. Cerberus Palus once contained a lake fed by Athabasca Valles and draining into Lethe Vallis. According to different researches, it could be a lake of water or lava. It is notable by giant plates (up to 50 km and more), similar to pack ice Drift ice, also called brash ice, is sea ice that is not attached to the shoreline or any other fixed object (shoals, grounded icebergs, etc.).Leppäranta, M. 2011. The Drift of Sea Ice. Berlin: Springer-Verlag. Unlike fast ice, which is "fasten ..., but possibly pieces of lava crust. Gaps between the plates contain spiral-shaped geological features, probably lava coils. References Links Map of the region Elysium quadrangle Plains on Mars {{Mars-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanology
Volcanology (also spelled vulcanology) is the study of volcanoes, lava, magma and related geological, geophysical and geochemical phenomena (volcanism). The term ''volcanology'' is derived from the Latin word ''vulcan''. Vulcan was the ancient Roman god of fire. A volcanologist is a geologist who studies the eruptive activity and formation of volcanoes and their current and historic eruptions. Volcanologists frequently visit volcanoes, especially active ones, to observe volcanic eruptions, collect eruptive products including tephra (such as ash or pumice), rock and lava samples. One major focus of enquiry is the prediction of eruptions; there is currently no accurate way to do this, but predicting eruptions, like predicting earthquakes, could save many lives. Modern volcanology image:Icelandic tephra.JPG, Volcanologist examining tephra horizons in south-central Iceland. In 1841, the first volcanological observatory, the Vesuvius Observatory, was founded in the Kingdom o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
