Can Delhi withstand a magnitude 7 earthquake? What needs to be done?

Delhi's vulnerability to seismic risks is growing. Experts urge urgent retrofitting and structural audits to safeguard buildings against higher-magnitude earthquakes

Delhi woke up to strong tremors on Monday morning as an earthquake of magnitude 4 on the Richter scale struck the national capital. While there were no reports of casualties or property damage, the tremors felt stronger due to the epicentre being within the city itself — near Dhaula Kuan. This raises a question: If the magnitude of the earthquake had been higher, could Delhi’s structures have withstood it?

 

The alarming reality is, nearly 80 per cent of the city’s buildings would not endure an earthquake of magnitude 7 on the Richter scale, warned AK Jain, former Commissioner of the Delhi Development Authority (DDA). With earthquakes becoming increasingly frequent, there’s no telling when a major seismic event might strike, he told Business Standard.

 

 

So, why is Delhi so vulnerable to seismic activity? And what needs to be done to safeguard the city from stronger earthquakes? Here’s a deep dive.

 

Why is Delhi prone to seismic activity?

  Delhi-NCR is prone to seismic activity due to its proximity to the tectonically active Himalayan region. The collision between the Indian Plate and the Eurasian Plate continues to cause stress, resulting in earthquakes.

 

The city lies in Seismic Zone IV, a high-risk area, indicating a fairly high seismic risk, with expected earthquakes of magnitude 5-6 on the Richter scale, and the potential for stronger ones in the range of 6-8. It also has several active fault lines, including the Delhi-Hardwar Ridge, which increase the likelihood of seismic events. Additionally, the soil in parts of Delhi, such as the Yamuna floodplain, is loosely compacted, amplifying seismic waves during earthquakes.

 

According to the Ministry of Science and Technology, citing research from the Wadia Institute of Himalayan Geology, Dehradun: “All the earthquakes in Delhi-NCR result from the release of strain energy accumulated due to the northward movement of the Indian plate and its collision with the Eurasian plate.”

 

Historical records emphasise Delhi’s vulnerability to earthquakes. Since 1720, the region has experienced five significant earthquakes, with two major fault lines — Delhi-Hardwar Ridge and Delhi-Moradabad Fault — running through the area. The 1803 Garhwal earthquake, with an epicentre near Uttarkashi (magnitude 7.0–7.9), caused significant damage in Delhi, including the collapse of the Qutb Minar’s cupola. Another notable earthquake in 1999, in Chamoli (magnitude 6.5), caused damage to several Delhi buildings despite its distance of 280 km.

 

Are Delhi’s buildings earthquake-proof?

  In 2017, the Delhi High Court noted that many buildings violated the National Building Code, lacking the necessary structural safety features. The prevalence of unauthorised constructions, which bypass safety regulations, compounds this risk.

 

The Bureau of Indian Standards (BIS) has established seismic codes, such as IS 1893 and IS 4326, which provide guidelines for earthquake-resistant designs. These codes stress anchoring structures to bedrock or stiff soils, especially in seismic zones, to minimise damage. However, implementation in Delhi has been inconsistent.

 

A recent survey by LocalCircles revealed that only 14 per cent of residents trust the earthquake resistance of their homes. Of the 15,392 respondents, 87 per cent reported that their municipal body had never conducted a safety audit on their homes or buildings.

 

AK Jain highlights a similar concern, pointing out that while the Delhi High Court has issued directions and the government has revised building bylaws, the core issue lies in enforcement. “Many illegal buildings in unauthorised colonies and urban villages have become five to six storeys high without any approved building plans. These structures often lack input from structural engineers, use substandard materials, and are not designed to withstand earthquake shocks,” he told Business Standard.

 

Soil conditions also pose challenges. A 2023 journal by HS Mandal from the National Centre for Seismology revealed that 75 per cent of the National Capital Region (NCR) is underlain by water-saturated, loose alluvial soils. These soils are susceptible to liquefaction during seismic events, which can lead to ground failure and severe structural damage.

 

What needs to be done?

  According to Jain, all buildings should undergo a structural audit, with the Municipal Corporation of Delhi (MCD) assisting owners with retrofitting, which means making an old building or structure stronger and safer.

 

The National Disaster Management Authority (NDMA) released guidelines for seismic retrofitting of deficient buildings in 2014. The process begins with an assessment to identify vulnerabilities, such as cracks, weak columns, or unstable foundations. Engineers conduct visual inspections, computer simulations, and non-destructive tests to predict how a structure might behave during an earthquake. 

(DDMA's retrofitting guidelines)

  Retrofitting methods include jacketing (adding a layer of concrete or steel around weak beams), wall strengthening (adding shear walls or braces), and base isolation (using flexible bearings to reduce shaking impact). Foundation strengthening and mass reduction (replacing heavy roofs with lighter materials) are also common approaches.

 

A collaborative effort involving the MCD, IIT, and DDA is necessary to address the issue, said Jain. A major hurdle, however, is the fear among residents that failing an audit could lead to their buildings being demolished. Jain emphasises the importance of reassuring residents that the goal is safety, not demolition.

 

“It is crucial to assure people that this will not happen and that the goal is to work together to ensure safety. The government should also step in to provide financial assistance for retrofitting efforts, ensuring that communities are supported in making their homes earthquake-resilient,” he said.