Small tremors may be signs of bigger quake in Bengal seismic zone, warn experts

Kolkata: The tremor that Kolkata witnessed on Friday afternoon was a seismic precursor to a stronger earthquake that could be brewing in the region, geologists warned."The quake that Kolkata experienced on Friday afternoon was a seismic precursor. The region has witnessed several earthquakes in the past six months. This indicates a major earthquake in the making," said seismologist Shankar Nath, who is also the vice-chancellor of Burdwan University.The earthquake measuring 5.5 on the Richter scale at Nayabazar, around 100 km east of Kolkata, occurred at 1.22 pm. A few hours prior to that, a 4.7 magnitude quake was witnessed in Nepal. West Sikkim was hit by a 3.7 magnitude earthquake an hour before. Earlier, Cachar in Assam had witnessed a 4.3 earthquake on Thursday."All the geological fault zones got active in the seismic zone. After a series of low-intensity earthquakes were witnessed in Sikkim in the last six months, other fault zones also got active in the northeastern states, Darjeeling Himalayas and Nepal. These can lead to a major earthquake," added Nath, who was also a former professor at IIT Kharagpur's department of geology and geophysics. Harendranath Bhattacharya, the former professor of geology at Presidency University, also agreed with Nath's observation. "One can predict a major tremor with near certainty, although it is difficult to say when it will happen," he said. If a major earthquake hits Sikkim, Bhattacharya warned that south Bengal, including Kolkata, could also witness a major impact."Friday's earthquake in Bangladesh was of moderate intensity. But Kolkata felt the tremor as the epicentre was located at 10 km from the surface. Kolkata witnessed tremors of around 3.5 magnitude," said Bhattacharya. According to experts, the region has multiple faults, including the Purulia-Bankura Western Bengal Basin marginal fault, Damodar fault, Calcutta-Mymensingh hinge zone or Eocene hinge zone. It can also be impacted by plate shifts in the Shillong seismic zone, the Eastern boundary zone, connecting Manipur, Mizoram and Myanmar, and the Eastern Himalaya zone.