Some 78,323 buildings will be destroyed completely if a 6-magnitude earthquake shakes Dhaka originating from its beneath, causing havoc throughout the densely populated capital city, says a government study.
In case of a 7.5-magnitude earthquake originating from Madhupur Fault, the study says, some 72,316 buildings in the city will be damaged totally while 53,166 partially.
It says if an 8.5-magnitude of tremor from the plate boundary of Fault-2 hits the region, some 238,164 buildings will be destroyed completely across the country.
Comprehensive Disaster Management Programme (CDMP) under the food and disaster management ministry conducted the study from February 2008 to August 2009.
There will be an economic loss of about US $ 1,112 million for only structural damage in case of a 7.5-magnitude earthquake from the Madhupur Fault, it estimates.
“Economic loss due to damage of structures will be US $ 650 million and US $ 1,075 million respectively in case of an 8-magnitude earthquake from the plate boundary-2 and in case of a 6-magnitude earthquake from under Dhaka city,” the study says.
Some 30 million tonnes of debris, equal to 2,880,000 truckloads (25 tonnes for per truck), will be generated if a 6-magnitude earthquake jolts the city from beneath of it.
A 7.5-magnitude earthquake from the Madhupur Fault will generate a total of 30 million tonnes of debris, killing some 131,029 people instantly and injuring 32,948 others.
According to the study, at least 10 major hospitals, 90 schools in the capital will be destroyed completely and another 241 hospitals and clinics, 30 police stations and four fire stations partially in case of a 7.5 magnitude quake.
Dr Maksudur Rahman, an urban environmental management and planning researcher, told UNB reporter Rafiqul Islam that Bangladesh is situated at a high risk zone for earthquake and an unprecedented human disaster may occur in the city anytime for even a moderate to heavy tremor.
Referring to three major earthquakes of the region, he said a powerful earthquake needs at least 100-150 years to be originated for a particular region and in that sense it is overdue for Bangladesh and parts of Assam, as 112 years have passed by since a heavy tremor from Dawki Fault hit the region. “So, Bangladesh is highly vulnerable to a powerful earthquake.”
He also stressed the need for demolishing old and risky buildings of the city as a first step towards minimising casualties in such natural disasters. “If we can maintain the Bangladesh National Building Code (BNBC) in constructing new structures, we can minimise causalities and damages to some extent,” Dr Rahman said.
Dr. ASM Maksud Kamal, an earthquake and tsunami expert of the CDMP, said, “As a number of moderate to heavy earthquakes are overdue for some parts of the country, including the capital, it is important to get ready for the possible disasters by raising safety awareness of people.”
Kamal, also a teacher of Geography and Environmental Science of Dhaka University, feared that if a quake of lower magnitude lasts for a minute it may destroy 80-90 percent of the urban concrete structures.
“Gas leakage management, power supply control, firefighting, alternative power generation, wireless communication system, heavy equipments for removing debris and emergency clinical facilities are the top priority areas for attention,” he said.
It is Professor Roger Bilham of Colorado State University in the USA who first came up with his recent research findings that major earthquakes might take place in the sub-Himalayan region, including Bangladesh.
Another study of Michigan University has pinpointed that Dhaka is one of the earthquake vulnerable city out of top cities because of its unplanned urbanisation.
A strong earthquake of 8.6-magnitude occurred in Assam on August 15 in 1950, killing 1,526 people. Another 8.1-magnitude quake hit Assam on June 12 in1897, killing 1,500 people. The casualties were less because of low density of population and fewer numbers of concrete structures at that time.