Experts on Friday warned that Dhaka remained at a high risk of a major earthquake, given the city's historical seismic records.
They urged immediate large-scale actions and precautionary measures to minimise potential devastating losses.
A 5.7-magnitude earthquake, with its epicentre only 13 kilometres from central Dhaka, jolted the city at 10:38am on Friday, shaking buildings for a few seconds.
It was the strongest quake felt in the capital in the past four decades.
The Bangladesh Meteorological Department (BMD) confirmed the magnitude at 5.7, while the US Geological Survey (USGS) measured it at 5.5.
The epicentre was located in Madhabdi, Narsingdi, at a depth of 10km.
According to the Fire Service and Civil Defence, several buildings in Dhaka and Narayanganj suffered damage.
The quake caused at least six fatalities and left more than 100 people injured across the country.
Rubaiyat Kabir, an official at the BMD earthquake monitoring centre, said this was the strongest and highest-magnitude earthquake to hit Dhaka and its surrounding areas in several decades.
Other parts of the country also felt slightly stronger tremors of magnitude 4.0 to 5.0, but those originated outside Bangladesh, he said.
He also said several major earthquakes had occurred in this region historically, which proved its status as an earthquake-prone zone.
A bigger earthquake could strike Bangladesh any time, but no one could say exactly when, he said.
Mehedi Ahmed Ansary, a professor in the civil engineering department at the Bangladesh University of Engineering and Technology (BUET), believes this is a wake-up call for Bangladesh.
He said such an earthquake was expected.
If a 6-magnitude earthquake hit, there was a real risk of widespread destruction, he also said.
Among the major historical earthquakes in this region was the devastating one in 1762, which measured 8.5 on the Richter scale.
Known as the "Great Arakan Earthquake," it caused serious damage in Chattogram, Feni, and even Cumilla.
Later, the 1897 Assam earthquake was measured at 8.7.
Ansary said people must be alert and cautious after Friday's quake as earthquakes of magnitude 7.0 were due to return.
In 1918, a 7.6-magnitude earthquake struck the Balishira valley in Sylhet, and in 1930, a 7.1-magnitude quake hit Dhubri in Assam, he also said.
According to the professor, major earthquakes tend to return every 150 years. Considering that, a 7-magnitude earthquake is due again.
Calling Friday's event a warning for Bangladesh, he said after the Rana Plaza collapse, garment buildings were inspected to determine structural safety.
A similar inspection was now needed for buildings in Dhaka because many structures were not constructed according to the building code, he said.
According to him, Dhaka has 2.1 million buildings.
Of them, 0.6 million are more than six-storey tall. These buildings face the highest risk if a major earthquake occurs.
He also said the World Bank had given Rajdhani Unnayan Kartripakkha (RAJUK) $180 million for earthquake preparedness and the related work, but the latter did not have the capacity to utilise it properly.
Momenul Islam, director (current charge) of BMD and a seismology expert, said, "This earthquake's epicentre was very close to Dhaka, which is why it was felt so intensely.
"Even if an earthquake of magnitude 7 or higher occurs in Rangamati or Khagrachari, we do not feel such a strong jolt in Dhaka. However, if this earthquake had lasted just five to seven seconds longer, many buildings in Dhaka would have collapsed. Dhaka and its surrounding areas never experienced an earthquake like this."
He also said, "It may seem that a 6-magnitude earthquake is just one point stronger than a 5-magnitude one. But that is not the case.
"A 6-magnitude earthquake has a vibrating tendency 10 times greater than a 5-magnitude one. Here, every fraction means its intensity is proportionally higher. Consequently, this earthquake's tendency has intensity over at least a 100-kilometre radius."
A 2024 RAJUK study warned that if a 6.9-magnitude earthquake struck the Madhupur Fault in Tangail, between 40.28 per cent and 64.83 per cent of Dhaka's buildings could collapse.
According to the assessment, the estimated death toll would vary depending on the time of day.
A quake of that scale could claim 0.21 to 0.31 million lives in the morning, 0.27 to 0.4 million in the afternoon, and 0.32 to 0.5 million at night.
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