Fear grips Delhi-NCR as powerful pre-dawn tremor triggers chaos

Residents of New Delhi woke up in terror in the early hours of Feb 17 as a massive tremor, accompanied by an explosion-like sound, shook the region. Many reported feeling a strong jolt before dawn. As it turned out, a 4.0-magnitude earthquake struck Delhi-NCR, with its epicenter located in Dhaula Kuan.

The National Center for Seismology (NCS) reported that the quake occurred at 5:36 am, at a depth of just 5 kilometers near Jheel Park in Dhaula Kuan.

Residents who were awake rushed out of their homes in panic, while many were jolted awake.

"I was in a deep sleep when I suddenly felt a jolt. My husband and I woke up immediately and rushed outside with our children," said 33-year-old Neha who lives in a high-rise in Noida.

"Since I live on the 7th floor, it's difficult to evacuate quickly, especially with children. As it's not safe to use lifts during earthquakes, rushing down the stairs in a panic is also risky," she told Education Post.

A 53-year-old woman from South Delhi described a loud, banging noise that sounded like an explosion. "I live alone on the 4th floor and didn’t know what to do. I just prayed to God," the woman told Education Post.

While Delhi is prone to seismic activity as it falls in Seismic Zone IV, residents said this quake felt stronger than usual.

According to experts, a 4.0-magnitude earthquake is considered moderate, but its shallow depth and proximity to densely populated areas amplified its impact.

Delhi has a history of moderate earthquakes due to both far-field sources (Himalayas, Afghanistan, China) and local faults.

A 2.6-magnitude earthquake struck Delhi in November 2023 at a depth of 10 km in the North district. A 3.4-magnitude earthquake also hit Delhi in May 2020 and had its epicenter near Wazirpur.

The strongest recorded earthquake, however, was recorded at 4.6 magnitude in 2007, about 6 km from today’s (Feb 17) epicenter.

Delhi sits near active fault lines, including the Delhi-Haridwar Ridge and the Mahendragarh-Dehradun Fault, making it seismically vulnerable.

What caused the quake?
NCS Director OP Mishra explained that this was not a plate tectonic earthquake, but rather caused by local geological factors known as in situ material heterogeneity.

"People felt the strong impact because of the shallow depth. Their panic was natural," he said.

He added that minor aftershocks of 1.0 to 1.2 magnitude could follow.

Unlike major earthquakes triggered by the Sohna or Mathura Faults, this tremor resulted from movement along a weak underground zone known as a 'lineament', which runs in a northwest-southeast direction.

The explosion-like sound was due to the shallow focus of the earthquake. According to the US Geological Survey (USGS), when the ground vibrates during an earthquake, it generates short-period seismic waves that reach the air and convert into sound waves, explaining the rumbling noise residents heard.