Earthquake today: 4.0 magnitude quake strikes Bangladesh

Earthquake today:⁠⁠⁠⁠⁠⁠⁠ A 4.0 magnitude earthquake shook Bangladesh on Sunday, 21 September 2025, according to India's National Centre for Seismology (NCS) statement shared in a social media post on the platform X.

The NCS data shared highlighted that the Bangladesh earthquake occurred at 11:49 a.m. (IST) at a shallow depth of 10 kilometres, making it susceptible to aftershocks.

“EQ of M: 4.0, On: 21/09/2025 11:49:36 IST, Lat: 25.04 N, Long: 91.57 E, Depth: 10 Km, Location: Bangladesh,” said the National Centre for Seismology in its post.

What are shallow earthquakes?

Shallow earthquakes are generally more dangerous than deep earthquakes. This natural phenomenon occurs because the seismic waves from shallow earthquakes travel a shorter distance to the surface, resulting in stronger ground shaking, potentially more damage to structures, and greater casualties.

According to a Daily Star report, it is estimated that there is an earthquake every 30 seconds somewhere around the world; however, the majority of those are too weak to be identified.

A 4.0-magnitude earthquake is equivalent to about 6 tons of TNT explosives, but because the Richter scale is a base-10 logarithmic scale, the amount of energy released increases exponentially: A magnitude 5.0 earthquake is about 200 tons of TNT, 7.0 is 199,000 tons, and 9.0 is 99,000,000 tons, as per the report.

An ANI report, citing the USGS data, said that nearly 99 million tons of TNT is enough to wipe out just about anything, and is the equivalent of about 25,000 nuclear bombs.

Bangladesh sits where the three tectonic plates—Indian, Eurasian, and Burma — meet. Currently, the Indian plate is moving in the northeast at a speed of approximately 6cm per year, and the Eurasian plate is moving north at a speed of 2cm per year above the Indian plate.

Bangladesh reportedly has five major fault zones: the Bogura fault zone, the Tripura fault zone, the Shilong Plateau, the Dauki fault zone, and the Assam fault zone.

Thus, Bangladesh has 13 earthquake-prone areas, and Chattogram, Chattogram Hill Tracts, and Jaintiapur of Sylhet remain in extreme risk zones. In 2022, Dhaka, the capital of Bangladesh, with 30,093 residents per square kilometre, was among the cities with the highest population density in the world. It has also been marked as one of the 20 cities most vulnerable to earthquakes in the world.

(With inputs from wire agency ANI)