32 earthquakes in 13 months in country, origins in low-risk regions too

Bangladesh is located at the junction of three earthquake-prone tectonic plates. So experts consider it natural that earthquakes will occur from time to time in the country. However, the worrying matter is that recently the tendency of earthquakes originating within the country has increased. In particular, earthquakes have increased in the country’s south-western region, which is known as a low-risk zone for earthquakes.

Experts think that this south-western region has come under tensional forces (opposing pulls) between two plates located on the country’s eastern and western edges. As a result, earthquake proneness in this region may have increased. They also think that a new fault may have formed in the south-western region, or an old fault may have become active again.

Experts believe that these earthquakes in the south-western region are not frightening. However, in their opinion, the increase in the number of earthquakes inside the country and in surrounding areas indicates a large earthquake. And proper preparation is needed to face such an earthquake. According to them the country lacks this considerably.

Yesterday, Friday afternoon, an earthquake shook various regions of the country including Dhaka. After that, the fear of earthquakes and ways to deal with them came up again for discussion. Yesterday’s earthquake originated in Ashashuni upazila of Satkhira. Its magnitude at the epicentre was 5.4 on the Richter scale, which is called a moderate earthquake.

Although tremors were felt in different parts of the country including the capital, naturally they were felt much more strongly at the epicentre in Satkhira. There, people came out on the streets leaving their houses and shops in panic. Many of them said they felt a strong jolt. The earthquake, which lasted a few seconds at 1:52 pm, spread panic in the district.

Abdul Ali, a resident of Ashashuni Sadar, told Prothom Alo, “Suddenly my two-storey house started shaking. Everyone in the family quickly came down.” Purbopod Mallik, a resident of Harinagar village adjacent to the Sundarbans, said that suddenly around noon his two-storey house shook in the earthquake.

Considering earthquake risk, the country has been divided into highly risky, moderately risky, and low-risk areas. Among these, the area from Lalmonirhat district in the north to Khagrachhari in the south-east is highly risky; the north-central region including Dhaka is moderately risky; and the southern and south-western regions of Barishal and Khulna divisions are considered low-risk areas.

In this low-risk area, a moderate earthquake originated yesterday in Satkhira. But not only yesterday—on Thursday a 3.2-magnitude earthquake originated in Kaliganj of Jhenaidah in the southwest. Also, on 3 February early morning, an earthquake originated in Kalaroa of Satkhira with a magnitude of 4.1. On 27 September last year, an earthquake of magnitude 3.5 occurred in Monirampur of Jashore.

The three earthquake-prone regions among which Bangladesh is located are the subduction zone in the east, the Dauki Fault in the north, and the Himalayan Frontal Thrust zone at the foothills of the Himalayas (stretching from Nepal to Arunachal).

Earthquake expert and former professor of the Geology Department at University of Dhaka, Humayun Akhter, told Prothom Alo that the Indian Plate is going under the Burma Plate to the east, which is called subduction. At the eastern edge the plate is sinking downward. But to the west, a large part of the same plate is relatively stable and resisting the pull toward the east.

Humayun Akhter compared this situation to stretching a rubber band. He said, when pulled from two sides, pressure and tension are created in the middle. If the tension exceeds the limit of elasticity, the rubber band snaps. Similarly, tension accumulating in the middle of a plate can reactivate an old fault at a weak point or create a new fracture. Then the accumulated energy is suddenly released—that is an earthquake.

He thinks that in this Satkhira incident an old fault may have been reactivated or a new fault may have formed. He believes that if focal mechanism analysis (which indicates the type of displacement of rocks along a fault or fracture of a plate) is obtained in the future, it will be understood whether it is a normal fault or a newly activated one.

However, Humayun Akhter reassured that there is no major active tectonic plate boundary in that area. So moderate earthquakes may occur there, but the risk of a very large earthquake is low.

Akhtarul Ahsan, deputy director of the Geological Survey Department who is doing a PhD on earthquakes at Auburn University in the United States, thinks the Satkhira earthquake was an aftershock of the 5.7-magnitude earthquake on 21 November last year.

Akhtarul Ahsan told Prothom Alo that the origin of the Satkhira earthquake was from a newly discovered 400-kilometre-long fault line extending from Kolkata to Jamalpur to Mymensingh. The Satkhira and Narsingdi regions fall within the hinge line (30-kilometre areas on both sides of the fault line) of this fault.

In Akhtarul Ahsan’s research, a new 400-kilometre-long fault line has recently been found from Kolkata through Jamalpur in Bangladesh to Mymensingh.

Data on earthquakes from 2016 to now have been obtained from the earthquake observation centre of the Bangladesh Meteorological Department (BMD). It shows that from mid-February 2025 to yesterday, 32 earthquakes originated inside the country and in border-adjacent areas. Among these, the highest number—10 earthquakes—originated in the greater Sylhet area. These earthquakes originated near the Dauki Fault.

Rubaiyat Kabir, officer-in-charge of the earthquake observation centre of the BMD, told Prothom Alo yesterday that since 2016 there has been no record of 32 earthquakes originating inside the country in just 13 months. The increase of earthquakes inside the country and in border areas is the manifestation of the huge amount of energy accumulated beneath the earth. It indicates a large earthquake, which has been said for a long time.

Although agreeing about the possibility of a big earthquake, professor Humayun Akhter has a different explanation regarding the increase of earthquakes in and around the country.

He said, “Compared to before, the effort to collect earthquake data in our country and neighbouring areas has increased. Earlier those were not there. Technology has also improved. So perhaps now we are getting more and more accurate earthquake-related information.”