Can living in a region that is rich in (rare) earth metal that has an inherently strong magnetic field provide any protection from cosmic radiation? Where are the strongest magnetic field other than the north or south pole and is there a map of these areas?
First of all, "rare earth magnet ore", meaning the ores of metals like neodymium (Nd) and samarium (Sm), is not magnetic at all. It only becomes a magnet once you make a magnet out of it. For example, one such magnet is Nd2Fe14B and it only becomes a magnet after neodymium is combined with iron and boron.
Naturally occuring neodymium ore is usually in the form of minerals such as bastnäsite (a rare earth carbonate) or monazite (rare earth phosphate) that are not magnetic.
It gets even worse!
Even if by some force of magic the rare earth ore would protect you from cosmic radiation, you now have two problems:
- Most rare earth ore also has significant amounts of the radioactive thorium and uranium. You do not want to live in these areas, as any "protection" from cosmic radiation will be more than compensated for by the background radiation of the place you are now living in.
- These are not nice places to live in. The three operating or recently operating rare earth extraction operations (aka mines) are in the desert. Bayan Obo in China, Mount Weld in Australia, and Mountain Pass in the United States.
Cosmic radiation are high-energy particles that create particle showers high up in the terrestrial atmosphere. Those particle shower are heavily beamed downwards, and although in principle some secondary shower products feel the local magnetic fields, effectively are not affected by the natural terrestrial field, let alone weaker local fields.
Those showers also create hard photon radiation (X-rays) which contribute to the local background radiation and those wouldn't react to any magnetic field.
Yes, there are maps that map out variations in the earth's magnetic field, example here http://science.gc.ca/eic/site/063.nsf/eng/97358.html. The large variations are primarily due to the presence of ferric materials, ie large deposits of material like magnetite. There are no areas of rare earth magnets as far as I know, given that rare earth magnets are made from rare earth minerals artificially sintered in a very strong magnetic field suggests you will not find them naturally. Even if you did find an area the effect on cosmic radiation would be very small. The magnetic field earth is weak but very large and extends far outside our atmosphere allowing the energetic cosmic and solar particles to be trapped and or slowed. Local magnetic anomalies wouldn't have the time to influence the particles much.
If the poles shift we will have to ride out the transition as best we can. I am not aware of any major extinction event being associated with prior pole shifts, but I could be wrong. You also have to consider when the poles shift the magnetic fields that induce the current magnetic anomolies will be different or missing so you wouldn't be able to depend your chosen location being safe.
So unless you want to live underground I don't believe there are areas where the local magnetic fields will protect you from cosmic radiation.
Magnetite is a type of iron ore and does not significantly affect the Earth's magnetic field. It would not protect you from cosmic radiation. However, cosmic radiation is more intense high in the atmosphere, so airline cabin crew and people living on high mountains are slightly more at risk. If you are worried about how to avoid radiation damage, the thing to watch out for is radon gas. Radon gas is released by the decay of uranium in granite rocks, and varies in different parts of Britain. In some places it can reach dangerous levels which would not be tolerated in a nuclear power station or research establishment. There are indeed maps available on the internet which show levels of radon gas throughout Britain. Cornwall is one of the high radon areas, whereas Herefordshire is a low to moderate area. Radon is invisible, tasteless and odourless, and emits high energy alpha particles (helium nuclei) to become a radioactive isotope of lead. Alpha particles are not very penetrating and can be stopped by a thin sheet of paper, but when inhaled or otherwise ingested can be very dangerous because of their ionising effect. If you live in a high radon area, it is best to keep your house well ventilated.
Although the other answers have correctly pointed out that this isn't a relevant thing on Earth, it should be mentioned that such an effect does occur on the Moon: it is the likely cause for the Lunar swirls. These are though to be the result of magnetic anomalies causing local shielding of the surface from solar wind. This effect prevents the regions from proton “sun tan”, i.e. they aren't as dark as the rest of the surface, which is what we can from Earth.
But those particles for which this shielding works on the Moon are already 100% shielded from the Earth surface through Earth's internal dipole field and through its atmosphere.
The magnetic field stops the charged particles mostly by trapping them along their fields lines (globally parallel to the ground at most latitudes, plunging to the ground near the poles (therefore allowing northern lights). If you 1up nature and build a massive electromagnet, you could at most create a secondary pole, which would act as particle channel to you, increasing the cosmic radiation you would suffer.