Produced by: Tarun Mishra Designed by: Manoj Kumar
Earth's deepest gravitational anomaly, known as the "gravity hole," lies 1,200 km southwest of India in the Indian Ocean. Spanning 3.1 million square kilometres, this region's sea level is 348 feet lower than surrounding areas due to its weak gravitational pull.
The gravity hole was first identified in 1948, but its origin remained a mystery until a 2023 study published in Geophysical Research Letters shed light on its formation.
Researchers traced the anomaly to the disappearance of the ancient Tethys Ocean, which existed between the supercontinents Laurasia and Gondwana.
Around 180 million years ago, when Gondwana broke apart, fragments of the Earth's crust slid beneath the Eurasian plate. These fragments eventually sank into the mantle, triggering changes deep below the Earth's surface.
About 20 million years ago, fragments from Tethys disrupted high-density material in the mantle, originating from the "African blob"—a massive magma formation under Africa, 100 times taller than Mount Everest.
Low-density magma plumes displaced crystallized magma in the mantle, reducing the mass and gravitational pull in the region, contributing to the gravity hole's formation.
The study's findings still require corroboration with earthquake data to confirm the existence of the low-density plumes beneath the gravity hole.
Understanding mantle processes beneath Earth's surface could also provide insights into similar anomalies on Mars, where such "blobs" are thought to exist, helping unravel planetary mysteries.