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This was one of the world's largest eruptions of the 20 century (VEI 5).
The Hubble telescope, for example, doesn’t take any measurements when it passes through the SAA and the International Space Station has extra shielding added to protect the equipment and astronauts.
It is a region in the South Atlantic Ocean where the magnetic field is weaker than it is expected to be at that latitude.
The Earth’s magnetic field protects the planet and satellites orbiting around Earth from charged particles floating around in space, like the ones that cause aurorae.
I was involved in a project which focused on glacial tillites [a type of rock formed from glacial deposits] from Greenland to look into inclination shallowing; which is a feature of the way magnetism is recorded in rocks that can lead to inaccurate calculation of palaeolatitudes [the past latitude of a place sometime in the past].
Accurate interpretation of the direction of the Earth’s magnetic field recorded by rocks is essential to reconstructing the positions of continents throughout time.
People like to look for signs that the field will reverse soon; could it be that the SAA is a feature of an impending (in geological time! So, it becomes important to understand the SAA in that respect too. If the SAA is something you can’t see, simply measure, how do you go about studying it?
Paleomagnetists can look to the rock record to understand the history of the Earth magnetic field.Volcanic rocks best capture Earth’s magnetic field because they contain high percentages of iron-bearing minerals, which align themselves with the Earth’s magnetic field as the lavas cool down after being erupted.They provide a record of the direction and the strength of the magnetic field at the time they have erupted.Authorities warned residents and tourists that no activity is allowed within 9 km (5.6 miles) from the crater, and within 12 km (7.4 miles) to the north, northeast, southeast and south-southwest.Residents are asked to remain calm and not to trust unverified sources.In this interview, EGU's Laura Roberts Artal speaks with Jay Shah, a Ph. student at Imperial College London, who is investigating the South Atlantic Anomaly, a patch over the South Atlantic where the Earth’s magnetic field is weaker than elsewhere on the globe. But it’s through rigorous application of physics to geology that paleomagicians can look back at the history of the Earth’s magnetic field recorded in rocks around the world.