After a 7.7 magnitude earthquake in Myanmar and an 8.2 magnitude earthquake in Thailand, Bangladesh also felt a 4.5 magnitude tremor. The earthquake started only 597 km from Dhaka, raising concerns about earthquake risks in Bangladesh. Experts warn that the energy stored in the Indo-Burma Subduction Zone and the Dauki Fault could be released anytime, causing a major earthquake in the country.
100-year seismic cycle
In 1918, an 8.0 magnitude earthquake hit the Bangladesh region, killing 150,000 people (Geological Survey of India, 1924). According to geologists, major earthquakes tend to happen every 100 years in the same area (University of California, Berkeley, 2015). Bangladesh has already passed this time frame in 2023. The number of small earthquakes has also increased significantly. According to Bangladesh Meteorological Department (2024), there were 28 earthquakes in 2017, 41 in 2023, and 54 in 2024.
Do small earthquakes mean a big one is coming?
According to the Seismic Gap Theory, small earthquakes release some of the stress in the Earth’s crust, reducing the risk of a big earthquake. For example, in California’s San Andreas Fault, small quakes have reduced the risk of a 6.0+ magnitude earthquake by 15-20% (Journal of Geophysical Research, 2008). But Bangladesh is different. A 2022 study from Dhaka University found that the Dauki Fault is storing energy at a rate of 1.6 cm per year. However, earthquakes smaller than 4.0 magnitude release only 0.01% of this energy. To prevent a major earthquake (7.5+ magnitude), the energy must be released over 200 years, which is not possible.
A report from the USGS shows that before Japan’s Tohoku earthquake (2011) and California’s Ridgecrest earthquake (2019), there were 20+ and 300+ small tremors recorded, respectively. In Bangladesh, the locked segment of the Indo-Burma Zone has not had a major earthquake in 500 years, meaning that an 8.0+ magnitude earthquake could happen. A 2023 study in Seismological Research Letters states that the probability of a major earthquake in this region increases by 23% every decade.
Bangladesh’s four major earthquake zones: What are the risks?
Northeast (Dauki Fault): According to the Journal of South Asian Studies (1998), this 300 km long reverse fault caused the 1897 Great Assam Earthquake (8.7 magnitude), leading to soil liquefaction and over 200 deaths in Sylhet. Currently, there is a 30% chance of a 7.5+ magnitude earthquake here (Journal of Asian Earth Sciences, 2022).
Southeast (Indo-Burma Subduction Zone): The Indian Plate is moving under the Burma Plate at a rate of 46 mm per year (University of Colorado, 2021). A magnitude 8.2-8.5 earthquake could cause a 9-meter-high tsunami, destroying Cox’s Bazar and Chattogram coasts.
Central (Dhaka-Narayanganj): According to RAJUK, 82% of buildings in Dhaka are not earthquake-resistant. BUET’s geology department warns that a 6.0 magnitude earthquake could turn the Buriganga’s soft soil into liquid, causing 70% of buildings to collapse.
Coastal (Sundarbans-Saint Martin): There is a risk of a tsunami similar to the 2004 disaster due to submarine faults and fractures beneath the coral reefs (Journal of Coastal Research, 2020).
Risk in Dhaka
An international organization, GIG-Japan (2023), has warned that a 7.0 magnitude earthquake in Dhaka could collapse 72,000 buildings and kill 21 million people. Explosions from gas and electricity lines, broken water pipelines, and collapsed flyovers could make rescue efforts difficult. The Fire Service and Civil Defense report that it took 7 days to rescue people from one collapsed building in Savar. If 72,000 buildings collapse, the situation will be unimaginable.
New research findings:
The Gutenberg-Richter Law (1944) states that for every 1,000 earthquakes of 3.0 magnitude, one earthquake of 6.0+ magnitude occurs. But in Bangladesh, the number of 3.0+ magnitude quakes in 2023 was 35% higher than the average (Journal of Seismology, 2023). According to a 2021 study in Nature Communications, the Indo-Burma Zone stores 3.5 meters of energy annually, which small earthquakes cannot release. A recent study from the University of Tokyo (2024) warns that the probability of an 8.0+ magnitude earthquake in Bangladesh is increasing by 2% every year.
Preparation is the only way
We cannot stop earthquakes, but we can prepare for them. According to the Tonankai Model from Japan (Bulletin of the Seismological Society of America, 2018), the probability of an 8.0+ magnitude earthquake in the Indo-Burma Zone increases by 1.5% every year. Dhaka must enforce strict building codes, raise awareness, and create emergency plans. Remember -- earthquakes do not kill people, but weak buildings and lack of preparation do.
Arghya Protik Chowdhury is a Student, Department of Environmental Science, Bangladesh University of Professionals.
