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Vema Fracture Zone
The Vema Fracture Zone is a fracture zone in the equatorial Atlantic Ocean. It offsets the Mid-Atlantic Ridge by 320 km to the left. Its transform valley has a depth of 5000m. The fracture zone can be traced for over 2500 km east to west. Exploration history From temperature data gathered from the deep ocean on the German Meteor expedition (1925-1927) Georg Wüst already suspected that there should be a passage through the Mid-Atlantic Ridge around latitude 9 North. The Vema Fracture Zone was then discovered in 1956 by G.R. Hamilton on board , with additional surveying taking place in the years 1959–1960. In the 1960s research was done by , , RV Chain, RV Argo and . The fault was subsequently explored by the French research vessel Jean Charcot in 1977 using its SeaBeam Classic multibeam echosounder, the French submersible Nautile and its mothership RV Nadir in 1989, the US {{ship, RV, Maurice Ewing in 1993, and the Russian RV Akademik Nikolay Strakhov in 1998, mak ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
USS Snatch (ARS-27)
USS ''Snatch'' (ARS-27), well known as Scripps RV ''Argo'' after conversion to scientific research, was a commissioned by the U.S. Navy during World War II and in service from 11 December 1944 through 23 December 1946. Her task was to come to the aid of stricken vessels. The ship is better known from her scientific research role as the Scripps Institution of Oceanography (SIO) research vessel RV ''Argo''. It is that name, apparently not formally recognized by Navy that maintained title to the vessel, found in the scientific literature and public releases about her wide ranging research voyages. U.S. Naval service ''Snatch'' was laid down on 28 September 1943 by the Basalt Rock Company in Napa, California; launched on 8 April 1944; sponsored by Mrs. S. B. Johnson; and commissioned on 11 December 1944. World War II service ''Snatch'' conducted her shakedown cruise off San Diego, California, and returned to San Francisco, California from where she steamed on 20 February 1945 for M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subsidence
Subsidence is a general term for downward vertical movement of the Earth's surface, which can be caused by both natural processes and human activities. Subsidence involves little or no horizontal movement, which distinguishes it from slope movement. Processes that lead to subsidence include dissolution of underlying carbonate rock by groundwater; gradual compaction of sediments; withdrawal of fluid lava from beneath a solidified crust of rock; mining; pumping of subsurface fluids, such as groundwater or petroleum; or warping of the Earth's crust by tectonic forces. Subsidence resulting from tectonic deformation of the crust is known as tectonic subsidence and can create accommodation for sediments to accumulate and eventually lithify into sedimentary rock. Ground subsidence is of global concern to geologists, geotechnical engineers, surveyors, engineers, urban planners, landowners, and the public in general.National Research Council, 1991. ''Mitigating losses from land subsi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sealevel
Mean sea level (MSL, often shortened to sea level) is an average surface level of one or more among Earth's coastal bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical datuma standardised geodetic datumthat is used, for example, as a chart datum in cartography and marine navigation, or, in aviation, as the standard sea level at which atmospheric pressure is measured to calibrate altitude and, consequently, aircraft flight levels. A common and relatively straightforward mean sea-level standard is instead the midpoint between a mean low and mean high tide at a particular location. Sea levels can be affected by many factors and are known to have varied greatly over geological time scales. Current sea level rise is mainly caused by human-induced climate change. When temperatures rise, mountain glaciers and the polar ice caps melt, increasing the amount of water in water bodies. Because most of human settlement and infrastructu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mid-ocean Ridge
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 rid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ridge
A ridge or a mountain ridge is a geographical feature consisting of a chain of mountains or hills that form a continuous elevated crest for an extended distance. The sides of the ridge slope away from the narrow top on either side. The lines along the crest formed by the highest points, with the terrain dropping down on either side, are called the ridgelines. Ridges are usually termed hills or mountains as well, depending on size. Smaller ridges, especially those leaving a larger ridge, are often referred to as spurs. Types There are several main types of ridges: ;Dendritic ridge: In typical dissected plateau terrain, the stream drainage valleys will leave intervening ridges. These are by far the most common ridges. These ridges usually represent slightly more erosion resistant rock, but not always – they often remain because there were more joints where the valleys formed or other chance occurrences. This type of ridge is generally somewhat random in orientation, often ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mothership
A mother ship, mothership or mother-ship is a large vehicle that leads, serves, or carries other smaller vehicles. A mother ship may be a maritime ship, aircraft, or spacecraft. Examples include bombers converted to carry experimental aircraft to altitudes where they can conduct their research (such as the B-52 carrying the X-15), or ships that carry small submarines to an area of ocean to be explored (such as the Atlantis II carrying the Alvin). A mother ship may also be used to recover smaller craft, or go its own way after releasing them. A smaller vessel serving or caring for ''larger'' craft is usually called a tender. Etymology In many Asian languages, such as Chinese, Japanese, Korean and Indonesian, the word ''mothership'' (, ja, 母艦, ko, 모함, id, Kapal induk, literally "mother" + "(war)ship") typically refers to an aircraft carrier, which is translated as "aircraft/aviation mothership" (, ja, 航空母艦, ko, 항공모함, ms, Kapal induk ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nautile
''Nautile'' is a crewed submersible owned by Ifremer, the French Research Institute for Exploitation of the Sea. Commissioned in 1984, the submersible can be operated at depths of up to . ''Nautile'' is capable of housing three people. It has a length of 8 m, still imaging cameras, two colour video cameras, and a number of flood lights. It is fitted with two robotic arms to allow remote manipulation. ''Nautile'' can stay under water for up to eight hours at a time. Two ships can act as mothership to ''Nautile'': ''Pourquoi Pas?'' and ''Atalante''. In its early days ''Nautile'' was launched from RV ''Nadir''. The vessel has been used to examine the wreck of the RMS ''Titanic'' and to search for the black boxes from Air France Flight 447 See also References External links * Nautile— specification from Ifremer website Nautile: miniature submarine— BBC news article Submarine to examine sunken oil tanker— New Scientist article Le Nautile— technic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Submersible
A submersible is a small watercraft designed to operate underwater. The term "submersible" is often used to differentiate from other underwater vessels known as submarines, in that a submarine is a fully self-sufficient craft, capable of independent cruising with its own power supply and air renewal system, whereas a submersible is usually supported by a nearby ship, surface vessel, very large floating structure, platform, shore team or sometimes a larger submarine. In common usage by the general public, however, the word "submarine" may be used to describe a craft that is by the technical definition actually a submersible. There are many types of submersibles, including both crewed and uncrewed craft, otherwise known as remotely operated vehicles (ROVs) or unmanned underwater vehicles (UUVs). Submersibles have many uses worldwide, such as oceanography, underwater archaeology, ocean exploration, adventure, equipment maintenance and recovery, and underwater videography. Histo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multibeam Echosounder
A multibeam echosounder (MBES) is a type of sonar that is used to map the seabed. It emits acoustic waves in a fan shape beneath its transceiver. The time it takes for the sound waves to reflect off the seabed and return to the receiver is used to calculate the water depth. Unlike other sonars and echo sounders, MBES uses beamforming to extract directional information from the returning soundwaves, producing a swath of depth soundings from a single ping. History and progression Multibeam sonar sounding systems, also known as ''swathe'' (British English) or ''swath'' (American English), originated for military applications. The Sonar Array Sounding System (SASS) was developed in the early 1960s by the US Navy, in conjunction with General Instrument to map large swaths of the ocean floor to assist the underwater navigation of its submarine force. SASS was tested aboard the USS ''Compass Island'' (AG-153). The final array system, composed of sixty-one one degree beams with a swa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Woods Hole Oceanographic Institution
The Woods Hole Oceanographic Institution (WHOI, acronym pronounced ) is a private, nonprofit research and higher education facility dedicated to the study of marine science and engineering. Established in 1930 in Woods Hole, Massachusetts, it is the largest independent oceanographic research institution in the U.S., with staff and students numbering about 1,000. Constitution The Institution is organized into six departments, the Cooperative Institute for Climate and Ocean Research, and a marine policy center. Its shore-based facilities are located in the village of Woods Hole, Massachusetts, United States and a mile and a half away on the Quissett Campus. The bulk of the Institution's funding comes from grants and contracts from the National Science Foundation and other government agencies, augmented by foundations and private donations. WHOI scientists, engineers, and students collaborate to develop theories, test ideas, build seagoing instruments, and collect data in diverse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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