National Center for Seismology said the earthquake struck at a focal depth of five kilometres in Delhi-NCR on February 17, 2025
| Photo Credit: Special arrangement

Strong tremors were felt in the national capital and adjoining regions as an earthquake of 4.0 magnitude struck the region early on Monday (February 17, 2025). The National Center for Seismology said the earthquake struck at a focal depth of five kilometres at 5:36 am.

After Delhi, NCR, tremor felt in Bihar also at 4.0 magnitude. The National Center for Seismology said the earthquake struck at a depth of 10 kilometres at 8:02 am.

Shallow earthquakes, originating five or 10 kilometres below the surface, tend to cause more damage than those originating deep below the surface.

Shallow earthquakes are between 0 to 70 km deep; intermediate earthquakes, 70 to 300 km deep; and deep earthquakes, 300 to 700 km deep.

An instance of the devastating effect of a shallow earthquake would be the 5.6 magnitude earthquake in Indonesia in Novermber 2022 that left more than 160 dead and hundreds injured as buildings crumbled and terrified residents ran for their lives on the main island of Java.

According to the U.S. Geological Survey, “There is not one magnitude above which damage will occur. It depends on other variables, such as the distance from the earthquake, what type of soil you are on, building construction” and other factors.

Why an earthquake’s depth matters

A quake’s destructive force depends not only on its strength, but also on location, distance from the epicentre and depth.

Quakes can strike near the surface or deep within the Earth. Most quakes occur at shallow depths, according to the U.S. Geological Survey.

Shallow quakes generally tend to be more damaging than deeper quakes. Seismic waves from deep quakes have to travel farther to the surface, losing energy along the way.

Shaking is more intense from quakes that hit close to the surface like setting off “a bomb directly under a city,” said Susan Hough, a USGS seismologist.

The epicentre for the strongest earthquake was 206 km southeast of the pilgrimage town of Joshimath in Uttarakhand and 284 north of Uttar Pradesh’s capital Lucknow. Photo: USGS

Four earthquakes, the strongest being of magnitude 6.2, jolted Nepal in quick succession with tremors reverberating through parts of north India including Delhi-NCR, the National Centre for Seismology (NCS) said on October 3.

An NCS official said the first quake of magnitude 4.6 struck west Nepal at a depth of 10 kilometres at 2:25 p.m., followed by the 6.2 magnitude jolt at 2:51 p.m.

Two more quakes (magnitude 3.6 and 3.1) hit the same region at a depth of 15 km and 10 km at 3:06 p.m. and 3:19 p.m., respectively.

The epicentre for the strongest quake was 206 km southeast of the pilgrimage town of Joshimath in Uttarakhand and 284 north of Uttar Pradesh’s capital Lucknow.

People in Delhi and the National Capital Region reported strong tremors after the second quake and rushed out of their offices and high-rise residential buildings. The Delhi Police urged them not to panic.

“We hope you all are safe. Please come out of your buildings to a safe spot, but do not panic. DO NOT USE ELEVATORS! For any emergency help, dial 112,” it said in a post on X.

Tremors were felt in Chandigarh, Jaipur and other parts of north India as well. The Police control room in the pink city said there was no information yet about losses.

Nepal lies in one of the most active tectonic zones (seismic zone IV and V) of the world, making the country extremely vulnerable to earthquakes.

According to the U.S. National Aeronautics and Space Administration, a 7.8 magnitude earthquake hit Nepal on April 25, 2015, killing more than 8,000 people and injuring over 21,000.