
	Where results make sense

Topic: South Atlantic Magnetic Anomaly

	South Atlantic Anomaly (Site not responding. Last check: 2007-10-13)
		The South Atlantic Anomaly is the region where Earth's inner van Allen radiation belt makes its closest approach to the planet's surface.
		It is produced by a "dip" in the Earth's magnetic field at that location, caused by the fact that the center of Earth's magnetic field is offset from its geographic center by 280 miles.
		The South Atlantic Anomaly is of great significance to satellites and other spacecraft that orbit at several hundred miles' altitude and at orbital inclinations between 35° and 60°; these orbits take satellites through the Anomaly periodically, exposing them to several minutes of strong radiation each time.
	pedia.newsfilter.co.uk /wikipedia/s/so/south_atlantic_anomaly.html (148 words)

	Inkaba yeAfrica
		South Africa is the only subcontinental region in the world, therefore, where a history of the elevation of its paleo-surfaces can be used with confidence to track paleo-mantle dynamics of the lower mantle in isolation from horizontal forces of plate tectonics.
		South Africa was part of the heartland of Gondwana and it has the world's best preserved terrestrial-marine linked sequences of volcanic rocks, sediments and fossils with which to track the break-up of this supercontinent, and its associated long-wavelength global climate and biodiversity changes.
		South Africa is surrounded by the two end-members of extensional-type continental margins: one produced during pure-shear perpendicular to the present southern Atlantic margin; the other through simple shear parallel to the margin of the southern Indian Ocean.
	www.hartrao.ac.za /inkaba/why_sa.php (2320 words)

	COB
		However, even in the NE Atlantic there is room for improved picking of magnetic anomalies and the COB as demonstrated by a recent high-resolution aeromagnetic survey flown in 2003 by NGU in the Lofoten area.
		Satellite derived gravity anomaly data and bathymetry data were used to derive the mantle residual gravity anomaly which then was inverted to give Moho depth.
		Magnetic anomaly map of Norway and adjacent ocean areas overlain with identified magnetic anomalies, fracture zones and spreading axes.
	www.geodynamics.no /cob.htm (535 words)

	Life Technology™ News: Pole Shift Imminent
		South-pointing magnetic flux moves from sunspots, which are intense magnetic loops near the equator of the sun, along “meridional flows” to the north magnetic pole, and vice versa.
		Whether the magnetic field is primarily molten-metal flow dynamics or electron current loops, or a combination of those and other factors, a magnetic pole reversal may be of significance to the search for clean energy generation and transportation.
		If earth magnetic anomalies become more frequent or are concentrated in certain areas, we could see disruption of existing electrical grids, even without the dramatic atmosphere expansion and radiation damaging to life and computers.
	www.lifetechnology.org /blog/2006/09/pole-shift-imminent.html (1836 words)

	Seafloor Magnetic Anomalies (Site not responding. Last check: 2007-10-13)
		Magnetic surveys of the ocean floor showed striking elongated anomalies, symmetric with respect to the ridge crest which always corresponds to a positive anomaly.
		Linear magnetic anomalies flanking the mid-Atlantic ridge south-west of Iceland.
		Oceanic magnetic anomalies are recognized by their shape and identified by a number (1 to 34, then M0 to M27).
	wwwrses.anu.edu.au /~jean/GEOL3005/PlateTectonics/Magnetic.html (409 words)

	ESA - Observing the Earth - Focus on our magnetic planet
		The South Atlantic Anomaly, as the experts call it, is one pressing reason why they are intensifying their exploration of the Earth’s magnetism.
		As gauged by the satellites, the main field is roughly 6,000 times stronger than the rock magnetism of the ocean floor, and 30,000 times greater than the influence of the oceanic tides.
		Magnetic variations drive electric currents in the mantle, the main region between the core and the crust.
	www.esa.int /esaEO/SEMV6K71Y3E_index_2.html (1236 words)

	Scientific Challenges of Magnetic Field Dynamics
		The problem of explaining the origin of the Earth's magnetic field was once ranked by Albert Einstein as among the three most important unsolved problems in physics.
		Although today it is widely recognized that the Earth's magnetic field is generated by a dynamo that operates in the fluid outer core, the details of how that dynamo works remain far from understood.
		This pattern is connected to the growth of the South Atlantic Magnetic Anomaly, an area in which the field at the Earth's surface is now about 35% weaker than would be expected.
	solidearth.jpl.nasa.gov /PAGES/mag02.html (320 words)

	Geomagnetic Polarity Timescale (Site not responding. Last check: 2007-10-13)
		The first marine magnetic anomaly based timescale was constructed by Jim Heirtzler and colleagues in 1968.
		It is based on the South Atlantic magnetic anomaly sequence and attempts to make the sea-floor spreading history smoothly varying over this region and then uses this timescale to fit the rest of the world's midocean ridge spreading systems.
		The Heirtzler et al GPTS was the original timescale based on the extrapolation of terrestial reversal records to magnetic anomalies.
	deeptow.whoi.edu /gpts.html (509 words)

	NOVA \| Magnetic Storm \| See a Reversal 5 \| PBS
		In the Glatzmaier-Roberts model, a reversal begins with additional north and south poles appearing at the core.
		This anomaly has not made it to the surface—a compass near this "area" would still point to true north—but the strength of the magnetic field is as much as 30 percent weaker at the surface.
		After a short period of instability, the north and south magnetic poles switch polarity.
	www.pbs.org /wgbh/nova/magnetic/reve-05.html (115 words)

	plate tectonics - seafloor spreading
		In addition, in the south Atlantic, some of the oceanic plateaus are also evident.
		Inclination of magnetic vector yields paleolatitude; declination the direction to the magnetic pole.
		Magnetic polarity reversals: in a sequence of lavas find NRM vectors for some ages that are subparallel but of opposed polarity to those above and below.
	maps.unomaha.edu /Maher/plate/week2/seafloor.html (887 words)

	Magnetic Pole Shift? - Satellites Showing Radiation Damage
		This forthcoming revolution is a reversal in the Earth's magnetic field, an event that occurs every 500 000 years or so.
		Commenting on the New York Times report, Kotze said that the decay in the Earth's magnetic field was becoming increasingly apparent in "the South Atlantic anomaly", a huge deviation in the Earth's magnetic field discovered with the help of the Hermanus Magnetic Observatory.
		The ESA's scientists believe that this anomaly, as revealed by the occasional "geomagnetic jerk" to which our part of the world is prone, will provide a clue to predicting the next "flip" in the Earth's magnetic field, now 250 000 years overdue - as these things go.
	www.rense.com /general54/pole.htm (633 words)

	The South Atlantic Anomaly (Henry Spencer)
		Most people know that the Earth's magnetic poles aren't located at its geographic poles, but it's less well-known that Earth's magnetic center is not at its geographic center either.
		In that area, known as the South Atlantic Anomaly, the Van Allen belts come down low enough that radiation intensity in low Earth orbit is noticeably greater there.
		This is troublesome both to astronauts and to sensitive electronics; for example, it's common for astronomy missions to suspend operations during passage through the SAA because the radiation causes unacceptably high noise levels in their sensors.
	yarchive.net /space/science/south_atlantic_anomaly.html (626 words)

	Earth loses its magnetism
		Magnetic reversals were always preceded by weakened magnetic fields, said Dr Gallet, but not all weakened fields bring on a flip-flop.
		Iron in lava, for example, points in the direction of the then-existing field and is frozen in that orientation as the lava cools and hardens.
		This happens all the time, but the effects would be increased during a magnetic reversal or diminished magnetic field.
	afgen.com /magnetic_field.html (1086 words)

	NOVA \| Magnetic Storm \| Impact on Animals \| PBS
		When I learned recently that our planet's magnetic shield is rapidly weakening and may be ready to reverse its polarity, causing compasses to point south, I immediately wondered what that would mean for leatherbacks and the many other species that use the magnetic field to orient themselves and find their way around.
		This suggested that the birds needed the magnetic field to be a certain intensity to be of use.
		There is no firm evidence that the many magnetic field reversals that have taken place throughout our planet's history (see When Compasses Point South) have coincided with or triggered extinctions.
	www.pbs.org /wgbh/nova/magnetic/animals.html (1598 words)

	CNN.com - Report: Earth's magnetic field fading - Dec. 12, 2003
		The strength of the Earth's magnetic field has decreased 10 percent over the past 150 years, raising the remote possibility that it may collapse and later reverse, flipping the planet's poles for the first time in nearly a million years, scientists said.
		Over the southern Atlantic Ocean, a continued weakening of the magnetic field has diminished the shielding effect it has locally in protecting the Earth from the natural radiation that bombards our planet from space, scientists said.
		As a result, satellites in low-Earth orbit are left vulnerable to that radiation as they pass over the region, known as the South Atlantic anomaly.
	www.cnn.com /2003/TECH/science/12/12/magnetic.poles.ap/index.html (347 words)

	SANAE - Research
		The South African SANAE base as well as the British and American, Halley and Siple bases lie beneath the mean position of the plasmapause, an important field-aligned surface, marking the boundary between the relatively cool plasma of ionospheric origin and the hotter plasma emanating from the solar wind.
		At about 60anddeg; magnetic latitude, SANAE IV is well situated not only because of its proximity to the plasmapause, but also because during periods of high geomagnetic activity it falls beneath the auroral oval, making it ideal for optical studies of the aurora.
		It is near the South Atlantic magnetic anomaly, which is of intrinsic interest as an energy sink and has been extensively studied by South African scientists.
	home.intekom.com /sanae/research.html (1733 words)

	Foster John : Prompt Mid-Latitude Electric Field Effects during Severe Geomagnetic Storms
		Solar wind density, velocity, and magnetic field parameters are presented in Figure 2 for the March 20-21, 1990 and the November 3-4, 1993 events.
		The equatorial anomalies are created as an eastward electric field uplifts the equatorial ionosphere, which subsequently diffuses down the magnetic field to produce density enhancements at somewhat higher latitudes.
		The response of the electron flux detector to energetic proton bombardment as the satellite traverses the South Atlantic magnetic anomaly is shown in the top panel and indicates that the field line of the topside perturbation lay near the peak of the effect of the anomaly (-26° magnetic latitude).
	www.haystack.mit.edu /~jcf/papers/slot.htm (4337 words)

	Foster John : Abstracts of Recent Scientific Publications
		These observations were confined to longitudes near the South Atlantic magnetic anomaly and, in the Nov 1993 case, the perturbation was coincident with the peak of the precipitating particle fluxes associated with inner-belt losses at the anomaly.
		During the March 20-22, 1990, magnetic storm, Millstone Hill radar and DMSP satellite observations detailed the conditions surrounding the occurrence of a SAR arc which was observed continuously through an 8-hour interval from dusk till past midnight in the North American sector.
		At antenna elevation angles between 4° and 20°, aspect angles between 0° and 10° (from perpendicularity with the magnetic field) are viewed at E region heights at invariant latitudes between 61°Å and 57°Å.
	www.haystack.edu /~jcf/papers.htm (3140 words)

	What is the South Atlantic Anomaly? (Site not responding. Last check: 2007-10-13)
		They are aligned with the magnetic axis of the Earth, which is tilted by 11 degrees from the rotation axis of the Earth, and are not symmetrically placed with respect to the Earth's surface.
		Above South America, about 200 - 300 kilometers off the coast of Brazil, and extending over much of South America, the nearby portion of the Van Allen Belt forms what is called the South Atlantic Anomaly.
		The data were collected by the South Atlantic Anomaly Detector (SAAD) aboard the ROSAT spacecraft.
	www.astronomycafe.net /qadir/q525.html (290 words)

	Plate Tectonics
		Magnetized rock samples of the same age from different continents point to different locations for the same magnetic pole, suggesting that if the continents were fixed the Earth had several north and south poles at the same time.
		Confirmed the 'theory of magnetic reversals '- A change in the Earth's magnetic field, in which the north magnetic pole becomes the south magnetic pole, and vice versa.
		Rocks of 'reversed polarity' point toward the present position of the Earth's south magnetic pole.
	mtsu32.mtsu.edu:11407 /100tectonics.html (1575 words)

	Earth Observation Magazine
		Intriguingly, this decay rate is characteristic of magnetic reversals, which are believed to occur on average, though with great variability, about once every half million years.
		The recent decay in our global magnetic field is due largely to field changes in the vicinity of the South Atlantic Ocean.
		Within an area known as the South Atlantic Magnetic Anomaly the magnetic field at Earth’s surface is decreasing, and is now about 35% weaker than would be expected for a global dipole.
	www.eomonline.com /Common/Archives/2003nov/03nov_booth.html (2783 words)

	[No title] (Site not responding. Last check: 2007-10-13)
		Lin and H. Yeh During the great magnetic storm of July 15, 2000, the ROCSAT-1 low earth orbiting satellite detected an unusually large region of density depletion at low latitudes (<35 o) in the southern hemisphere while the storm enhanced density (SED) was observed in the northern hemisphere.
		The zonal electric field component was eastward corresponding to outward convection, and the radial electric field component on the magnetic meridian plane was outward corresponding to westward convection.
		In general both components of the observed convective electric fields were enhanced inside the density depletion region and reduced inside the density enhancement region.
	image.gsfc.nasa.gov /publication/abstract/2005_lin_yeh.txt (221 words)

	SurferMag Message Boards: How to survive 2012????????? (Site not responding. Last check: 2007-10-13)
		If all the compasses in the world started pointing south rather than north, many people might think something very strange, very unusual, and possibly very dangerous was going on.
		Such reversals in the Earth's magnetic field, they'd tell you, are, roughly speaking, as common as ice ages.
		It appears that they do by looking at the magnetized strips in rock but this is do in part to the wandering of the poles and continental drift (technically plate tectonics but who keeps track of the correct theory names anyway).
	forum.surfermag.com /forum/showflat.php?Cat=0&Number=1139283&Main=1138923 (4184 words)

	EARTH CHANGES: Magnetic Field Reversal
		After the survey, all angles were recorded on the plats relative to magnetic north.
		Ideally, a survey using magnetic bearings would include the contemporary variation, permitting current variation to be factored in.
		Ocean rift magnetic anomaly - Robert J. Distinti presents theory that doesn't use any form of pole-reversal to explain the paleomagnetic evidence.
	www.pureenergysystems.com /news/2005/02/27/6900064_Magnet_Pole_Shift (2283 words)

	Another interesting feature is that there is a South Atlantic Anomaly (SSA) which has very low magnetic field strength (Site not responding. Last check: 2007-10-13)
		During this process, the south magnetic pole migrated north and for a while became a band of south magnetic flux smeared around the Sun’s equator.
		The fact that Earth’s magnetic field is currently asymmetric combined with the fact that a magnetic field depression has formed would lead one to believe that the Earth’s magnetic pole components are being restructured.
		The process of Earth magnetic pole reversals may be quite complex and studying changes in the Sun’s magnetic pole reversals can provide very valuable insight that may directly apply to a similar process within the Earth.
	personals.galaxyinternet.net /tunga/GC2.htm (459 words)

	Atlantic Ocean maps from Omni Resources - International Map & Guidebook Specialists.
		This map illustrates the total magnetic anomalies of the Atlantic Ocean adjacent to Western Europe.
		Illustrates the Bouguer gravity signature of coastal Europe and the free-air anomalies of the adjacent Atlantic Ocean.
		Atlantic Ocean--Bathymetry and Plate Tectonic Evolution of the North Atlantic Ocean.
	www.omnimap.com /catalog/int/atlanoc.htm (178 words)

Try your search on: Qwika (all wikis)