If a tsunami generates in the Andaman seas and hits the Sunderbans, Calcutta could be among the worst hit, a study by IIT Kharagpur has revealed.

“A simulation of the possible impact of a tsunami originating in the Andaman belt following an earthquake of magnitude 6 or more on the Richter scale shows the killer waves would reach the Sunderbans in an hour. If the timing coincides with high tide, the wave is likely to flow along the Hooghly and cause major floods in Calcutta and other settlements along the river,” Prasad Kumar Bhaskaran, an associate professor in the department of ocean engineering and naval architecture at the IIT, told Metro on Sunday afternoon.

“Bengal may be less affected than Orissa, Tamil Nadu and Andhra Pradesh because of its steep beach with enough soft mud to act as a buffer. The thick silt in the Hooghly, too, will act a barrier for the surging waves as they flow down the river but the city’s vulnerability results from its huge population load and lack of preparedness,” said Bhaskaran.

The institute’s study of a possible impact of tsunami generated in the northern Indian Ocean covers the Bay of Bengal and the Arabian Sea.

The Sunderban delta and the Calcutta region feature on the map of south Asia’s tsunami-vulnerable areas, which was prepared on the basis of an analysis of the tsunami that struck on December 26, 2004. The Bengal-Bangladesh coast was unaffected by it.

The Andaman belt, as stated by Bhaskaran and several geologists, is extremely active seismically and generates innumerable earthquakes of low intensity. “The belt, known as the 90 degree east ridge, is very active seismically,” said Tapas Ghatak, a geologist who had once worked with the state government.

“The region had experienced a tsunami after the Chittagong earthquake in 1762. In a similar situation, Calcutta will no doubt be severely affected, especially because of its high population density and poor preparedness to combat a disaster,” said Sugata Hazra, a professor at the oceanography department of Jadavpur University.

The Chittagong quake caused permanent submergence of 155.40sq km. The IIT study, which aims to draw a tsunami travel atlas for 37 countries if a quake strikes in the Indian Ocean, has identified 45 vulnerable spots along the east and west coasts of India.