Geophysicists have discovered the reason for the anomaly in the Indian ocean

2017-10-21 16:44

Geophysicists have discovered the reason for the anomaly in the Indian ocean
The minimum level of gravity can be felt in the ocean close to Sri Lanka: this anomaly has long been known, but to explain it was only now.

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The images from space our Earth looks almost perfectly round, but steals a lot of the water that covers most of its surface, reports Rus.Media. In fact, the planet is full of bumps, ridges and deep valleys covered where the thick continental tectonic plates, and much more subtle oceanic.

All this creates uneven mass distribution in the lithosphere of the Earth, and if it was covered with water, not spinning, if the ocean had no currents, no waves, the thickness of the water layer in different areas would be different, and the maximum difference between the highest and lowest areas was close to 200 g. This conditional “sea level” forms the shape of the geoid, which gives a more accurate idea of the shape of our planet than a perfect sphere, visible from earth orbit.

One of the most prominent details of this will be Reduction of the geoid in the Indian ocean (Indian Ocean Geoid Low, IOGL), with its deepest point at the level of -106 m, located to the South of Sri Lanka. Explanation of the mass deficiency that creates this anomaly remains one of the most interesting problems of modern Geophysics. However, it now seems to be solved thanks to the efforts of Atri Ghosh (Attreyee Ghosh) and his colleagues from the Indian Institute of science in Bangalore, and also from Germany.

Article of scientists publishes the journal Geophysical Research Letters, and briefly about work tells the message of the American geophysical Union (AGU).

Map of the geoid surface

Geophysicists have modeled the convection currents of the mantle – powerful currents, in which the hotter and light material rises to the surface, and the dense and cold descends.

Anomaly IOGL has been linked with an excess of less dense and light matter. But where does he? As a rule, such areas are associated with the action of mantle plumes rising up hot flows. However, field observations do not find anything suitable nearby.

On the other hand, a little further West lies the African superplume. Scientists have shown that India is quickly moving away from Africa, directs part of the mantle flows of this vast province to the East. They reach just to the center of the anomaly in the Indian ocean; it seems that the mystery of the largest gravity anomalies resolved.