Over the past century, progress in the study of sciences and the development of new technology has reached considerable heights, but despite this, there are still unexplored or poorly studied places and phenomena on our planet, which sometimes have unusual "side" effects. The magnetic anomaly is one of them.
Earth's magnetic field
Deep under our feet, under the thickness of the Earth's crust, there is something that has been warming the planet Earth from the inside for many billions of years - a huge ocean of viscous hot magma. This magma consists of many substances, including metals, which conduct electric current very well. All over the planet, microscopic electrons move under the surface of the Earth, creating an electric, and with it a magnetic field.
Moving geomagnetic poles
The Earth's magnetic field has two poles: the North Geomagnetic Pole (located in the southern hemisphere of the planet) and the South Geomagnetic Pole (located in the northern hemisphere of the planet). One of the most widely known unusual phenomena in the Earth's magnetic field is the geographic movement of the geomagnetic poles.
The fact is that a magnetic field is influenced by several factors at once, contributing to its unstable position. This is interaction with the axis of rotation of the Earth, and different pressures of the earth's crust in different parts of the planet, and the approach / removal of cosmic bodies (Sun, Moon), and, to a greater extent, the movement of magma.
The magma flow is a giant mantle river that moves under the influence of solar radiation and the rotation of the Earth from west to east. But, since the size of this river is huge, it, like an ordinary river, cannot move steadily evenly. Of course, in ideal conditions, the channel of the mantle river should run along the equator. In this case, the geographic and magnetic poles of the Earth would coincide. But natural conditions are such that during its movement magma searches for zones of least resistance to the flow (zones of low crustal pressure) and moves towards them, shifting the magnetic field and geomagnetic poles.
Magnetic anomalies
The instability of the mantle river affects not only the magnetic poles, but also the emergence of special zones called "magnetic anomalies". Magnetic anomalies do not have a permanent location, they can become stronger / weaker, differ in size and cause.
The most common phenomenon is local magnetic anomalies (less than 100 square meters). They are found everywhere, are located in a chaotic manner and arise mainly under the influence of mineral deposits located too close to the Earth's surface.
Other magnetic anomalies are regional (up to 10,000 square kilometers). They arise due to changes in the magnetic field. Their size and strength depends on the structure of the earth's crust in a given area. For example, when a flat terrain passes into a mountainous one, there is a sharp rise in the earth's crust, both on the surface of the Earth and below it. With such a change in the relief, the speed of movement of the magma flow increases sharply, particles of matter collide with each other and oscillations in the magnetic field arise. Some of the most famous regional anomalies are Kursk and Hawaiian.
The largest are continental magnetic anomalies (over 100,000 square kilometers). They owe their origin to faults in the Earth's crust and the impact of the earth's axis. For example, the East Siberian anomaly due to the shift of the earth's axis in this direction. In addition, mountain ranges have divided the mantle river into two branches flowing in different directions, as a result of which the compass needle will be in the western declination in this area. Off the coast of Canada, the situation is different. There is a huge area of contact of the mantle river with the Earth's crust, as a result of which a magnetic field intensity arises, which, in turn, pulls the Earth's axis towards itself.
However, the most interesting magnetic anomaly is in the south of the Atlantic Ocean. The magnetic river there turns in the opposite direction, thereby changing the magnetic field in such a way that this area is opposite to the rest of the southern hemisphere. This anomaly is famous for the fact that several times the astronauts flying over it broke small electronics.
Magnetic anomalies are scattered all over the planet, do not have a permanent location, they appear and disappear, become stronger or weaker. Among other things, years of research have shown that the planet's geomagnetic field is weakening, and magnetic anomalies are getting stronger.
