Sri Lanka, Feb. 25 -- A magnitude 5.1 earthquake hit the Bay of Bengal off the Odisha and West Bengal coasts around 6:10am on Tuesday. Tremors felt in Kolkata triggered panic even as there were no reports of immediate damage in the city and its surrounding areas.

Susmita Deb, a Kolkata resident, said she had just woken up when the earthquake struck and everything started shaking. "It lasted for a few seconds," she said.

Kolkata falls under seismic zone 4, which is susceptible to the high damage risk of severe earthquakes. There are four seismic zones with zone 5 being the most and zone 2 the least active. Around 11% of the country falls in zone 5, 18% in zone 4, 30% in zone 3, and the remaining in zone 2.

A magnitude 4.0 earthquake str...