Gravity holes happen as the Earth gravitational field is not uniform due to variations in density and mass distribution.
- There are some areas which are denser than the others and this variation in the density create differences in the gravitational attractions, that forms geoids.
- A massive region in the Indian Ocean, about 1,200 kilometres southwest of the southernmost tip of India, has such a low pull of gravity that the sea level of the Indian ocean over the “hole” is around 106 metres below the global average.
- This dip in the ocean is called Indian Ocean geoid low (IOGL). It was discovered in 1948 during a survey by Dutch geophysicist Felix Andries Vening Meinesz.
- A team of researchers from the Indian Institute of Science (IISc), Bengaluru has solved the reasons behind the Gravity holes in India Ocean.
- In a research article published in the journal Geophysical Research Letters, Debanjan Pal and Attreyee Ghosh, document what they believe caused the gravitational anomaly.
- After looking at computer-simulated models of the past 140 million years, they found the remains of an ancient ocean about 965 kilometres below the Earth’s crust, just under Africa.
- The researchers found that the presence of lighter materials in the upper to mid-mantle, were responsible for the gravity low in this region, hence that led to the formation of the IOGL.
- The scientists believe that this mantle structure beneath the Indian Ocean was probably produced by the leftovers of a long-lost Tethys Ocean’s seabed.
