The Mystery of the ‘Gravity Hole’ Beneath the Indian Ocean
Recently researchers from IISc, Bengaluru have identified the reasons for the formation of ‘Gravity Hole’ in the Indian Ocean.
This gravity hole is also known as the Indian Ocean Geoid Low (IOGL). This hole is more than three million square kilometers wide.
IOGL is located just south of Sri Lanka. Here the Earth’s gravitational pull is weakest. As a result, the sea level here is 100 meters lower than the global average. The shape of the Earth is not actually spherical. It is flattened at both the poles and bulges at the equator.
As a result of this, as well as variations in the gravitational pull caused by other factors such as the mass of the Earth’s crust, the Earth is irregularly shaped.
These anomalies are called “geoids” on a map with an imaginary line joining Earth’s mean sea level. The origin of these anomalies is due to irregularities in the gravitational field.
IOGL is said to be the lowest geoid anomaly on Earth. The researchers found that the IOGL was formed by plumes of molten rock rising from the bottom edge of the Tethys Ocean.
The superheated flow of material from the African super plume began to move eastward and eventually reached the bottom of the IOGL.
The African super plume is a large section of Earth’s mantle that conducts heat from near the core to the crust. Therefore, the presence of lighter elements or materials in the middle mantle below the IOGL is responsible for the low gravity in this region.
Source – Business Standard
