The magnetic field reliably protects the Earth from cosmic radiation and the solar wind, which is able to destroy the Earth’s gas shell. Its existence is explained by the processes occurring inside the planet with the iron core and the molten metal surrounding it.
However, there are places on Earth where a deviation of the magnetic field from normal values is observed. The concept of magnetic anomalies arises.
About what are the areas of magnetic anomalies, physics tells quite extensively. Understanding the causes of their occurrence, the possible consequences of occurrence, as well as the patterns of physical processes in these areas is a powerful tool for studying the magnetic field and bowels of the Earth.
What are areas of magnetic anomaly
The protective magnetic field undergoes constant changes. When observing the Earth's magnetic field, the question of what are the areas of magnetic anomalies is relevant. Indeed, it is in such areas that mineral deposits are discovered, and technical equipment also fails.
Magnetic anomalies are called areas in which there is a deviation of the magnetic field from the corresponding values in neighboring areas. The reason for the occurrence of most of these phenomena are considered underground deposits of magnetic iron ores.
The question of which areas are called magnetic anomalies also implies an understanding of the magnitude of the effect of a magnetic field with deviated parameters. Depending on the scale, such anomalies are divided into:
- Continental, the area of which is from 10 to 100 thousand km 2.
- Regional, occupying from 1 to 10 thousand km 2.
- Local, the hallmark of which, as a rule, is the occurrence of iron ore in the bowels of the earth.
The continental zones include the East Siberian magnetic anomaly. And the most prominent representative of local regions is the Kursk magnetic anomaly.
Kursk magnetic anomaly
The unusual behavior of the Earth's magnetic field in the region of Belgorod and Kursk was first noted in 1773. The cause of the anomaly in this area was iron ore deposits discovered in the bowels of the earth. The magnetic field in certain areas of the Kursk Magnetic Anomaly (KMA) exceeds the norm by 2-3 times.
The amount of iron in the ore basin is 50% of global iron ore reserves. And the Kursk magnetic anomaly is considered the most powerful on the planet. The territory of KMA covers an area of more than 160,000 km 2 , covering 9 regions of Central and Southern Russia.
Brazilian magnetic anomaly
The inhabitants of the southern regions know firsthand what magnetic regions of anomaly are. Along the Brazilian and South African shores, there is the phenomenal Brazilian Magnetic Anomaly (BMA). The uniqueness of the BMA is that the cause of its occurrence is the "failure" of the Earth's magnetic field.
The discovery of the BMA belongs to the Koro space telescope. In 2011, his measurements of proton fluxes going from the Sun to the Earth indicated a region in which particles passed farther than elsewhere on the planet. Subsequent observations and studies pointed to the difference in the magnetic field indices from normal values existing in the region.
BMA is the zone with the weakest magnetic field. Protons here can drop to 200 kilometers from the surface of the planet. Due to the high level of radiation radiation over the territory of the BMA equipment fails, planes, satellites and even spaceships fail. As a result of the influence of the Brazilian magnetic anomaly, space objects such as the Hubble telescope and the Phobos-Earth interplanetary station were affected.
Strip magnetic anomalies
Considering the question of what are the areas of magnetic anomaly, one cannot but mention the oceans. Along the ocean ridges for hundreds and even thousands of kilometers are the so-called strip anomalies with an ordered structure. The values of the magnetic field in such zones are above or below normal. Such deviations are called positive or negative anomalies of the magnetic field. A similar feature of the magnetic field of the oceans is based on the spreading of the oceanic crust and rock magnetism.