Nation on edge: Major quake looms on Dawki-Madhupur fault

Pressure has been building for about 400 years on the tectonic plates beneath Bangladesh, specifically on the Dawki and Madhupur faults. When this strong pressure is released, the resulting earthquake could reach a magnitude of 8 on the Richter scale. This would cause extensive damage to central, northern, and north-eastern regions of Bangladesh, including Dhaka. The number of casualties would surpass all previous records. This information was revealed in a research paper published in June of this year by the geology department of the Lamont-Doherty Earth Observatory at Columbia University, USA.

Bangladesh is located at the junction of three dynamic plates (Indian, Eurasian, and Burma plates). The mutual movements of these plates create tectonic fractures, known as faults. These faults are the primary cause of earthquakes. The Earthquake Observation and Research Center of the Bangladesh Meteorological Department stated that the Dawki Fault is one of the main earthquake faults in the country. It is the most dangerous for the northern and eastern regions, especially Sylhet and Mymensingh. Additionally, there is the Madhupur Fault near Tangail, close to Dhaka; a fault line stretching from Teknaf to Myanmar; and several isolated faults in the Chittagong Hill Tracts. These have placed the capital Dhaka and most parts of the country at risk of a major earthquake.

A powerful earthquake in the Dawki Fault in 1787 changed the course of the Brahmaputra River. Then, 110 years later in 1897, an earthquake known as the 'Great India Earthquake' also occurred on this fault. It caused extensive damage to Assam, Meghalaya, and the city of Dhaka. The Dawki Fault extends from the Shillong Plateau in India towards the Sylhet and Mymensingh regions of Bangladesh. This fault line is the most risky for the northern and north-eastern parts of the country, and there is a possibility of a major earthquake in this region.

Next is the Madhupur Fault, located only 70 miles away from the capital Dhaka. Major earthquakes of magnitude 7.5 were felt on this fault in 1822 and 1918. It is a significant fault located in the central part of Bangladesh. There is also the Teknaf-Myanmar fault line. A powerful earthquake of magnitude 8.5 or higher occurred here in 1762. This earthquake caused Saint Martin's Island to rise by three meters. The faults in the Chittagong Hill Tracts are also quite important. Comprising several small faults in areas including Rangamati and Bandarban, this fault line has made the region earthquake-prone. However, as there are no faults in the southern and south-western parts of the country, the Khulna and Barisal divisions are comparatively less risky for earthquakes.

In the middle of September this year, two moderate earthquakes were felt in the country. Their magnitudes on the Richter scale were 5.9 and 4, respectively. The epicenter of the second earthquake was within the country, in Chhatak, Sylhet. This falls within the Dawki Fault. In February 2024, two or three earthquakes of magnitude 4 or slightly higher occurred in this region. Therefore, it can be said that the area is becoming increasingly risky.

Md. Rubayet Kabir, the acting officer-in-charge of the Earthquake Observation and Research Center of the Bangladesh Meteorological Department, told Views Bangladesh, "There is no geological fault line near Dhaka capable of producing an earthquake of magnitude 8 or 9. However, there is a fault line near Madhupur (60 km away) that can cause an earthquake of magnitude 7 to 7.5. If an earthquake of such magnitude occurs there, there is a possibility of extensive damage and loss of life in the capital Dhaka. But there is a possibility of an earthquake of magnitude 8 or higher in the Dawki Fault in the Sylhet and Mymensingh regions. If it happens, the geographical structure of that region could change. And the scale of damage would be devastating."

Professor Mehedi Ahmed Ansari of the Civil Engineering Department at BUET said, "Dhaka city and the surrounding districts have soft and red soil. Furthermore, most residential areas of the capital have been built by filling up various types of water bodies. In filled and soft soil, the seismic waves are much stronger even for low-magnitude earthquakes. On the other hand, most buildings in Dhaka are not resistant to moderate or severe earthquakes. Therefore, if a magnitude 7 earthquake occurs in this city, casualties and damage will be very high. Although Sylhet, Mymensingh, and Rangpur regions have hard soil, they could experience earthquakes of magnitude 8 or higher. This could change the geographical position of the country's northern and north-eastern regions. A terrible catastrophe could befall this region."

On the Richter scale, earthquake magnitudes are classified as: 1 to 4.99 (mild), 5-5.99 (moderate), 6-6.99 (strong), 7-7.99 (major), and 8 and above (great). In a seismic zoning map created by BUET researchers, Bangladesh has been divided into three zones. Zone-1 is at high risk of earthquakes. 43 percent of the country's area falls under this zone.

Approximately 40 percent of the country's area, including parts of Sylhet, Sunamganj, Moulvibazar, Habiganj, Panchagarh, Rangpur, Gaibandha, Mymensingh, Netrokona, Thakurgaon, Sirajganj, Tangail, Jamalpur, Sherpur, Kishoreganj, Kurigram, Rangamati, Khagrachhari, Brahmanbaria, and Cox's Bazar, is in Zone-1. Zone-2, which has a moderate risk level, includes areas like Dhaka, Tangail, Comilla, Feni, Natore, Magura, Manikganj, Meherpur, and Rajshahi. This covers 41 percent of the country's area. Additionally, 19 percent of the country's area is at low earthquake risk. The islands and chars in the southern regions, including Khulna and Barisal divisions, are at the lowest risk of earthquakes.