National as well as international scientists and researchers have forecast that a major earthquake, measuring 8.2 to 9 on the Richter scale, could be building up beneath the surface of Bangladesh, putting at risk at least 140 million people of the country, including 15 million of Dhaka city. “A massive fault could trigger a cataclysmic earthquake beneath Bangladesh, parts of eastern India and Myanmar. The fault is entirely in the sub-surface," said Prof. Michael Steckler, a geophysicist at Columbia University's Lamont-Doherty Earth Observatory and lead author of a paper published this week in ‘Nature Geoscience’. "It'd certainly be one of the largest (recorded quakes). I suspect it might be at the lower end (of the 8.2–9 scale), but I can't rule out a really large one," he added. Earthquake experts in Bangladesh have also agreed with the observation of Prof. Steckler, who has been studying the movements of the plate beneath the densely populated country since the 2004 Sumatra tsunami which killed 230,000 people. The new research found what has long been suspected, but there was no data to prove that the pressure has actually been building up. Data collected since 2004 by Prof. Steckler's team has found that a juncture between major tectonic plates in the region is locked and loaded up with stress. Measurements found convergence of tectonic plates at the rate of 13–17mm per year on an active, shallowly dipping and locked megathrust fault, said the study. "We can see the strain building up, we can see the motion of the plates, but we can't estimate when something might happen," Prof. Steckler told media-persons. He even said, "We don't know whether it's going to be tomorrow or after 500 years."
A 250-km by 250-km zone, including the mega city of Dhaka, is at significant risk. This area sits atop a deep sediment that could liquefy in many places in the advent of a big quake. Entire buildings and infrastructures could sink into the sand and soil.
Prof. ASM Maksud Kamal, head of the disaster science and management department of Dhaka University, agreed with the observations of Steckler. He said this is a part of the observations by Bangladesh’s experts, adding that the observation is not an assumption but the result of measurements by instruments.
He said the earthquake with a magnitude of over 8 is called a severe earthquake, which may wreak massive damage and destruction. “The damage and destruction depend on the depth of the epicentre, distance, structural tolerance and on the soil on which the buildings are built,” he said, adding that the structures built on marshy land are more prone to danger from an earthquake than those on normal soil.
The experts advised the government to take combined measures to minimise the damage from the quake by ensuring strict adherence to the Building Code of 1993, preparing the zoning map which shows the types of soil that support various types of structures.
Prof. Mehedi Ahmed Ansary, a teacher ar the civil engineering department of the Bangladesh University of Engineering and Technology (BUET), said the mega earthquake might arise from the fault at the Bangladesh-Myanmar border line. In the event of an earthquake measuring over 8 in magnitude, it would wreak havoc in Dhaka, Chittagong and Sylhet zones, all of which come under the earthquake zone, he said.