The tremor, recorded at a depth of 75.3 km, occurred at 3:20am UAE time

A 6.4 magnitude earthquake struck the southeast Indian Ocean early Sunday morning, according to the National Centre of Meteorology (NCM).
The tremor, recorded at a depth of 75.3 km, occurred at 3:20am UAE time in the southeast Indian Ocean, as reported by the NCM’s National Seismic Network.
It goes back to tectonic plates: they are always moving, albeit only slowly, but do get stuck at their edges due to friction. Earthquakes occur due to a sudden slip on a fault — or a sudden release of stress along faults — in the earth's crust.
As these plates continue to move, it leads to a steady build-up of pressure in the rock strata on both sides of a fault — until the stress becomes so great that it is released in a sudden, jerky movement.
An earthquake releases energy in “waves”, measured using the Richter scale. These waves travel through the earth's crust and cause the shaking that we feel.