Closeness to Himalayas, 3 fault lines make city prone to quakes

National Centre for Seismology data shows that the region has recorded 446 earthquakes between 1993 and 2025 within a 50 sq km radius of Monday’s epicentre.

Located just south of the earthquake-prone Himalayas and the presence of three active fault lines running Delhi means that the city sits in a seismically active region, experts said on Monday after an early morning tremor jolted millions of residents.

Tremors of earhtquake were felt at around 5.30am on Monday. (PTI)

Data from the National Centre for Seismology (NCS) shows that the region has recorded 446 earthquakes between 1993 and 2025 within a 50 sq km radius of Monday’s epicentre. These tremors, ranging from magnitudes of 1.1 to 4.6, highlight the high seismic activity of the area.

The first factor contributing to Delhi’s vulnerability is the presence of the Sohna, Mathura, and Delhi-Moradabad fault lines. Additionally, Haryana, which surrounds Delhi, has seven fault lines of its own, further increasing the risk of seismic disturbances to the Capital.

The Bureau of Indian Standards (BIS) classifies India into four seismic zones, from Zone II (low intensity) to Zone V (very severe). Delhi and the NCR fall in Zone IV, indicating a “severe” seismic risk. This means earthquakes are not uncommon in the region, and Monday’s tremor is not an anomaly. Delhi’s proximity to the Himalayas, which falls in Zone V, also makes it prone to aftershocks from larger quakes in the mountain belt.

“Delhi and NCR are in seismic Zone IV due to the number of fault lines that crisscross the region. These faults constantly release energy, resulting in frequent mild earthquakes that often go unfelt. Additionally, Delhi’s proximity to the Himalayan region, which is in Zone V, makes it particularly vulnerable. If a major earthquake of magnitude 8 or above occurs in the Himalayas, it could cause significant damage in Delhi,” said AK Shukla, former head of the National Centre for Seismology (NCS).

While Delhi’s earthquakes have been less intense than those in the Himalayas, its potential earthquake magnitude is estimated to be up to 6. However, historical data shows at least four instances since 1700 when the threshold has been exceeded, including the 6.8 magnitude Mathura earthquake in 1803.

A 2015 study by the Union ministry of earth sciences titled “Seismic Hazard Microzonation” identified locations on the Yamuna floodplains as most vulnerable to earthquakes, particularly the densely populated residential areas of East Delhi. Other high-risk areas include Lutyens’ Delhi, Sarita Vihar, Paschim Vihar, Wazirabad, Karol Bagh, and Janakpuri. Meanwhile, relatively safer zones include JNU, AIIMS, Chattarpur, Naraina, and Vasant Kunj, which may better withstand strong tremors due to geological factors.

Despite past efforts to earthquake-proof Delhi’s infrastructure, particularly after major earthquakes in 2008 and 2015, retrofitting initiatives have yielded limited results. Only a few old buildings have been structurally reinforced, including the Delhi Secretariat, Delhi Police and PWD headquarters, Ludlow Castle School, Vikas Bhawan, Guru Tegh Bahadur Hospital, and the Divisional Commissioner’s Office.

Experts emphasise that structural integrity alone is not enough; the type of subsurface soil also plays a crucial role in amplifying an earthquake’s impact.

“Dhaula Kuan has hard rock beneath it, which can reduce seismic intensity. In contrast, areas like Lodhi Road have loose soil, which can amplify tremors. However, data suggests that the fault lines in Delhi are not highly active, which is why most recent earthquakes have been below magnitude 5. For larger quakes, one must look to the Himalayan belt,” said JL Gautam, former head of NCS.