Sylhet people in fear after series of earthquakes

After four mild tremors and several aftershocks between Saturday morning and afternoon, Sylhet experienced another light tremor of magnitude 2.8 at 4:35am yesterday, which panicked people again.

Experts warned that these series of light tremors could be sign of a major quake and requested the authorities concerned to take precautionary measures.

A six-storey residential buildings was found tilted in Sylhet city's Ponitula area after the earthquakes.

Prof Syed Humayun Akhter, of geology department at Dhaka University, and also the director of Dhaka University Earth Observatory, said the location of the tremors were at the hilly terrain right in the upstream of the Sari river in Jaintiapur upazila, which is the eastern part of Dauki Fault Line.

Dauki Fault Line is a major fault along the southern boundary of the Shillong Plateau that may be a source of destructive seismic hazards for the adjoining areas, including in northeastern Bangladesh.

Dauki Fault Line is a 300km fault line stretching from south of the Shillong Plateau, highland region in eastern Meghalaya state of northeastern India, to the northern border of Mymensingh and Sylhet divisions.

Prof Humayun said, "These mild tremors may be a sign of a major earthquake as the fault line has the strain energy to cause a 7.5-8.5 magnitude earthquakes. On the other hand, the strain energy can be released through small tremors like the ones Sylhet experiencing."

The geology professor and a meteorologist of BMD both said awareness was the key to stay safe during an earthquake and no way, panic and rumour can be spread.

Meanwhile, the Sylhet City Corporation (SCC) started inspecting vulnerable buildings in the city yesterday afternoon and giving the building owners different instructions. There are 24 risky buildings, according to the survey of the corporation conducted in 2016.

Sayeed Ahmed Chowdhury, a meteorologist of Bangladesh Meteorological Department (BMD) in Sylhet, said, "Data is required from three seismic centres to confirm the epicentre of an earthquake, but these were so mild and of low depth that we get signal in one seismic centre and have only the aerial distance pointing towards the Dauki Fault Line."

Prof ASM Maksud Kamal, of disaster science and management department at Dhaka University, said geographically and historically Sylhet region is an earthquake-prone area.

"There are five fault lines in the Sylhet region and if any of it releases accumulated energy, there would be an earthquake. So, the government agencies should make preparation to minimise the loss and damage to lives and properties," he said.

Apart from the Great Bengal earthquake that struck in 1897, there was another earthquake known as Sreemangal earthquake that happened in 1917. Usually, a major earthquake takes place in a 100-year interval, he said.

"So, two major earthquakes is due for over a century ... ," he said.

In another development, SCC officials visited the tilted building and asked its residents to move to another place.

However, Sylhet City Corporation's Chief Executive Officer Bidhayay Roy Choudhury said the building might have leaned years before the tremors.

"We're looking into the matter. Since yesterday [Saturday], we're getting rumours like roads were damaged, but there was no truth behind all these widespread rumours," he said.

He added that the city corporation started awareness campaign, keeping a possible large earthquake in mind.

Abdul Alim Shah, public relations officer of SCC, said, "We've ordered six shopping complexes -- Madhuban Market, Mitali Mansion, City Super Market, Raja Mansion, Surma Market and Samobai Bhaban -- to remain closed for 10 days as these are risky. And we're alerting the citizens to remain prepared for a major tremor."