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32-595: The Stokes Magnetic Anomaly (also known as the Stokes Magnetic Anomaly System, SMAS, New Zealand Junction Magnetic Anomaly, JMA, great Nelson magnetic disturbance, Junction Anomaly, Campbell Magnetic Anomaly System, CMAS ) is a magnetic anomaly on the Earth's surface that extends from New Caledonia to the Chatham Rise with complexity consistent with the theory of plate tectonics . It

64-608: A base station repeatedly or by having another magnetometer that periodically measures the field at a fixed location. Second, since the anomaly is the local contribution to the magnetic field, the main geomagnetic field must be subtracted from it. The International Geomagnetic Reference Field is usually used for this purpose. This is a large-scale, time-averaged mathematical model of the Earth's field based on measurements from satellites, magnetic observatories and other surveys. Some corrections that are needed for gravity anomalies are less important for magnetic anomalies. For example,

96-407: A complete loss of signal. The last data packet received indicated that the booster had flown only 227 kilometers at signal loss. Telemetry data indicated that abnormal vibrations began affecting the booster at T+90 seconds and vehicle breakup occurred seven seconds later. A search plane located the impact site. It was not clear what had caused the vibrations, but the decision was made to go ahead with

128-455: A regional survey of deeper rocks. In shipborne surveys, a magnetometer is towed a few hundred meters behind a ship in a device called a fish . The sensor is kept at a constant depth of about 15 m. Otherwise, the procedure is similar to that used in aeromagnetic surveys. Sputnik 3 in 1958 was the first spacecraft to carry a magnetometer. In the autumn of 1979, Magsat was launched and jointly operated by NASA and USGS until

160-490: A remanent magnetization or remanence. This remanence can last for millions of years, so it may be in a completely different direction from the present Earth's field. If a remanence is present, it is difficult to separate from the induced magnetization unless samples of the rock are measured. The ratio of the magnitudes, Q = M r / M i , is called the Koenigsberger ratio . Interpretation of magnetic anomalies

192-444: A sensitivity of 10 nT or less. There are three main types of magnetometer used to measure magnetic anomalies: In ground-based surveys, measurements are made at a series of stations, typically 15 to 60 m apart. Usually a proton precession magnetometer is used and it is often mounted on a pole. Raising the magnetometer reduces the influence of small ferrous objects that were discarded by humans. To further reduce unwanted signals,

224-450: A series of parallel runs at a constant height and with intervals of anywhere from a hundred meters to several kilometers. These are crossed by occasional tie lines, perpendicular to the main survey, to check for errors. The plane is a source of magnetism, so sensors are either mounted on a boom (as in the figure) or towed behind on a cable. Aeromagnetic surveys have a lower spatial resolution than ground surveys, but this can be an advantage for

256-667: Is displaced by approximately right angle changes in direction for a total of 1,000 km (620 mi) running down the western side of New Zealand from the Northland Peninsula in the North Island to Fiordland but then exiting New Zealand's South Island on its Otago east coast. The Stokes Magnetic Anomaly has been related to magnetic anomaly extending in Australia as the east Lachlan Fold Belt or New England Fold Belt as an extension of where it commences near

288-479: Is named TMA-2, and one in the Olduvai Gorge is found in 2513 and retroactively named TMA-0 because it was first encountered by primitive humans. Sputnik 3 Sputnik 3 ( Russian : Спутник-3 , Satellite 3) was a Soviet satellite launched on 15 May 1958 from Baikonur Cosmodrome by a modified R-7/SS-6 ICBM . The scientific satellite carried a large array of instruments for geophysical research of

320-571: Is named after Captain (later Admiral) John Lort Stokes by G. C. Farr in 1916 as he described it first although such naming has proved controversial, hence many of the alternative names. The magnetic declinations were observed by Captain Stokes when captaining HMS Acheron and Commander (later Admiral) Byron Drury in HMS Pandora between 1851 and 1853. The Stokes Magnetic Anomaly has been characterised for over 3,000 km (1,900 mi) and

352-405: Is primarily permanent magnetization carried by titanomagnetite minerals in basalt and gabbros . They are magnetized when ocean crust is formed at the ridge. As magma rises to the surface and cools, the rock acquires a thermoremanent magnetization in the direction of the field. Then the rock is carried away from the ridge by the motions of the tectonic plates . Every few hundred thousand years,

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384-425: Is removing short-term variations in the field from external sources; e.g., temporal variations which include diurnal variations that have a period of 24 hours and magnitudes of up to 30 nT, probably from the action of the solar wind on the ionosphere . In addition, magnetic storms can have peak magnitudes of 1000 nT and can last for several days. Their contribution can be measured by returning to

416-434: Is usually done by matching observed and modeled values of the anomalous magnetic field. An algorithm developed by Talwani and Heirtzler(1964) (and further elaborated by Kravchinsky et al., 2019) treats both induced and remnant magnetizations as vectors and allows theoretical estimation of the remnant magnetization from the existing apparent polar wander paths for different tectonic units or continents. Magnetic surveys over

448-408: The 8A91 booster lifted from LC-1 and all appeared normal for over a minute into the launch. Around 1 + 1 ⁄ 2 minutes, things went awry. The strap-on boosters broke away from the core and the entire launch vehicle tumbled to earth 224 km (139 mi) downrange. Ground crews monitoring radar tracking data from the booster noticed the trajectory angle change to negative numbers, followed by

480-604: The R-7 intercontinental ballistic missile , also known by its GURVO designation as 8K71. The original plan envisioned a sophisticated laboratory limited to 1,000 to 1,400 kg, of which 200 to 300 kg would be scientific instruments. It was intended to be launched during the International Geophysical Year as the first satellite by the Soviet Union but ended up being the third due to problems developing

512-505: The R-7 for a satellite launch was ready before Object D could be finished. Worried at the prospect of the United States launching a satellite before he could, Sergei Korolev decided that the relatively simple "Prosteyshiy Sputnik-1" ("Simple Satellite 1", or PS-1) , also known as Sputnik 1 , would be the first satellite to be launched instead. Sputnik 2 (PS-2) was also ready and therefore launched earlier than Object D. Sputnik 3

544-438: The backup booster and satellite. The engines would be throttled down at T+85 seconds in the hope of reducing structural loads. Since the booster did not carry sufficient instrumentation to determine the source of the vibrations, which ultimately proved to be a phenomenon resulting from the propellant tanks emptying, it would end up being a recurring problem on lunar probe launches later in the year. The satellite had separated from

576-408: The changes in mass resulted in modifications to the flight plan--the core stage would be throttled down and the strap-ons throttled up 25% prior to their jettison. An interstage section replaced the radio equipment bay at the top of the booster, and the telemetry package was also moved here. The launch was planned for 20 April, but technical delays meant that several more days were needed. On 27 April,

608-509: The direction of the magnetic field reverses . Thus, the pattern of stripes is a global phenomenon and can be used to calculate the velocity of seafloor spreading . In the Space Odyssey series by Arthur C. Clarke , a series of monoliths are left by extraterrestrials for humans to find. One near the crater Tycho is found by its unnaturally powerful magnetic field and named Tycho Magnetic Anomaly 1 (TMA-1). One orbiting Jupiter

640-503: The downside, telemetry data indicated that vibration affected the launch vehicle again and it came close to meeting the same fate as its predecessor. While no Soviet satellite had been in orbit since the end of Sputnik 2 in April 1958, Sputnik 3 weighed about 100 times as much as the heaviest of the three active American satellites, and exceeded their combined scientific-data abilities. It was an automatic scientific laboratory spacecraft. It

672-434: The extensive scientific experiments and their telemetry system. Despite earlier work done by Mikhail Tikhonravov , much of the satellite's design had little precedent. The creation and use of pressurized equipment, long-range communications systems, automated switches, and a metal construct to work in Earth orbit were all uncharted territories. By July 1956, OKB-1 had completed the preliminary design, but modifications to

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704-474: The launch vehicle and was recovered near the crash site largely intact. It was taken back to the Baikonur Cosmodrome for refurbishment, but an electrical short started a fire inside the electronics compartment and it could not be reused. The backup booster and satellite were launched successfully on the morning of 15 May, specifically chosen as it was the anniversary of the R-7's maiden flight. On

736-415: The oceans have revealed a characteristic pattern of anomalies around mid-ocean ridges. They involve a series of positive and negative anomalies in the intensity of the magnetic field, forming stripes running parallel to each ridge. They are often symmetric about the axis of the ridge. The stripes are generally tens of kilometers wide, and the anomalies are a few hundred nanoteslas. The source of these anomalies

768-687: The spring of 1980. It had a caesium vapor scalar magnetometer and a fluxgate vector magnetometer. CHAMP , a German satellite, made precise gravity and magnetic measurements from 2001 to 2010. A Danish satellite, Ørsted , was launched in 1999 and is still in operation, while the Swarm mission of the European Space Agency involves a "constellation" of three satellites that were launched in November, 2013. There are two main corrections that are needed for magnetic measurements. The first

800-635: The surveyors do not carry metallic objects such as keys, knives or compasses, and objects such as motor vehicles, railway lines, and barbed wire fences are avoided. If some such contaminant is overlooked, it may show up as a sharp spike in the anomaly, so such features are treated with suspicion. The main application for ground-based surveys is the detailed search for minerals. Airborne magnetic surveys are often used in oil surveys to provide preliminary information for seismic surveys. In some countries such as Canada, government agencies have made systematic surveys of large areas. The survey generally involves making

832-421: The upper atmosphere , concentration of charged particles , photons in cosmic rays , heavy nuclei in cosmic rays, magnetic and electrostatic fields , and meteoric particles. The onboard Tral-D tape recorder, intended to store data for later transmission to Earth failed, limiting data to what could be gathered while the satellite was directly visible from ground stations. Because of this failure, Sputnik 3

864-530: The upper atmosphere and near space . Sputnik 3 was the only Soviet satellite launched in 1958. Like its American counterpart, Vanguard 1 , Sputnik 3 reached orbit during the International Geophysical Year . On 30 January 1956, the USSR Council of Ministers approved a project to launch an artificial Earth satellite using the R-7 rocket. Nicknamed "Object D", it would be the fifth type of payload built for

896-556: The vertical gradient of the magnetic field is 0.03 nT/m or less, so an elevation correction is generally not needed. The magnetization in the surveyed rock is the vector sum of induced and remanent magnetization : The induced magnetization of many minerals is the product of the ambient magnetic field and their magnetic susceptibility χ : Some susceptibilities are given in the table. Minerals that are diamagnetic or paramagnetic only have an induced magnetization. Ferromagnetic minerals such as magnetite also can carry

928-568: The western Challenger Plateau and Lord Howe Rise . This gives an age of up to 83 million years before present in its formation but alternatively, it may be extended to represent the earliest ocean crust formed between New Zealand and Marie Byrd Land in Antarctica so could be even older. Magnetic Anomaly Magnetic anomalies are generally a small fraction of the magnetic field. The total field ranges from 25,000 to 65,000  nanoteslas (nT). To measure anomalies, magnetometers need

960-495: Was conically shaped and was 3.57 m (11.7 ft) long and 1.73 m (5.68 ft) wide at its base. The satellite weighed 1,327 kg (1.46 tons) and carried twelve scientific instruments. After 692 days in orbit and completing thousands of orbits, Sputnik 3 reentered the atmosphere and burned up on 6 April 1960. It was powered by silver-zinc batteries and silicon solar cells. Sputnik 3 included twelve scientific instruments that provided data on pressure and composition of

992-501: Was essential for understanding the geology of Zealandia as a mainly underwater continent. It extends from 700 km (430 mi) south of New Caledonia to almost the eastern edge of the Campbell Plateau . Over much of its length it has peaks about 30 km (19 mi) to 50 km (31 mi) apart, although this is not the case for much of its New Zealand west coast course. Where the anomaly crosses New Zealand it

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1024-466: Was launched by a modified R-7 Semyorka missile developed for satellite launches, the Sputnik 8A91. The 8A91 was a transitional design between the initial 8K71 test model R-7 and the operational 8K74, which had yet to fly. Improvements in manufacturing processes were used to reduce the gauge of the slosh baffles in the propellant tanks and cut down on weight. The engines were slightly more powerful and

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