Seismic Activity in Delhi and New Delhi

Delhi, India’s capital territory, is a massive metropolitan area in the country’s north. New Delhi is the capital of India and a part of the National Capital Territory of Delhi. Considering many other daily problems of a big city like New Delhi (traffic, environmental pollution, water, power shortages, etc.), the issue of seismic risk has not drawn the attention that it should, if looking at the damage it might cause to the city¹. Many are simply relying on the belief that major earthquakes are not expected in the area and are thus not considering the fact that even a weaker earthquake once every few years could cause great damage to the whole country.

Delhi has had many damaging earthquakes in the past and is placed in a high seismic zone (zone IV out of V) located within a distance of 200-400 km from different locations of the main boundary thrust fault. It is prone not only to damaging earthquakes in or near Delhi but due to its peculiar geological setting it could also sustain strong shaking due to a large earthquake in the Himalayas.

Unfortunately, most buildings in Delhi may not meet Indian standards on aseismic constructions and may be considered deficient from a seismic safety viewpoint. Thus, there is a real potential for a great earthquake disaster in Delhi¹.

At this point, it is essential to notice that most death and destruction in an earthquake are caused by the collapse or damage of man-made constructions. Building earthquake-resistant buildings could reduce a lot of damage and using the earthquake forecasting system could enable people to get timely information about future earthquakes in order to take appropriate measures.

The highest earthquake magnitude experienced in Delhi in about a century was on July 27, 1960. The magnitude 5.6 earthquake caused partial damage to New Delhi. A seismic damage survey by the Central Public Works Department put the damage at about Rs 5 lakh².

Picture 1: New Delhi.

While it is true that New Delhi is unlikely to be at the epicenter of a moderate to large earthquake, earthquakes with an epicenter in the Himalayan mountains, which are located at a distance of 280-350 km, could also cause threat damage to India’s capital.

For example, an earthquake of a magnitude over 7.0 in the Shimla to Dehradoon/Pithoragarh (or western Nepal) ranges could cause tall structures in New Delhi to fall like dominoes. Taking into account that the number of high buildings in New Delhi has risen sharply in the last three decades or so, we can see that the consequences of an earthquake even several hundred kilometers from New Delhi could cause significant losses to the city and consequently to the whole country².

One of the latest earthquakes that struck New Delhi occurred on April 12, 2020. A magnitude 3.8 earthquake struck northeast of New Delhi and around 5 miles (8 kilometers) from Khakhra. Even though we’re talking about a small-scale earthquake, it was felt by many people, since it occurred during the lockdown and most people were at home. However, this was a great reminder for Indians that even if they live in areas that are not earthquake-prone, they are never entirely safe from it¹.

Most recently, the 1999 magnitude 6.5 Chamoli earthquake took place around 280 km from Delhi. Such a moderate earthquake does not normally cause damage at such a large distance. And yet, several buildings in Delhi sustained non-structural damage, likely due to the peculiar geological and geotechnical features of this area¹.

Additionally, we can take the example of the 1993 magnitude 6.5 earthquake in Maharashtra, India, which killed more than 30 % of its population. The region used to be considered safe from earthquakes and had been placed in the lowest seismic zone (zone I)¹.

It is therefore seen that Delhi and New Delhi are both prone to severe earthquake damage both by nearby earthquakes and by large earthquakes occurring in the Himalayas.

Picture 2: Seismicity in India.

If an earthquake tremor were to reach Delhi and New Delhi, it is possible that the number of fatalities, injuries, and infrastructure damage could go beyond the statistics. Such a disaster in the country’s major commercial, industrial, and most populous city could cause huge economic and political implications which would affect the entire country and not just the population of New Delhi or Delhi.

A valid question at this stage is: should one be concerned about an earthquake that has a very low probability of occurrence when Delhi faces so many day-to-day problems in regards to the environment, noise, traffic, water, power shortages, and so on?

Considering the potential for a huge disaster, we cannot afford to ignore the earthquake problem in New Delhi, Delhi, and India overall.

This leads to the question: can we hope to achieve seismic safety in Delhi? The answer is: yes.

Solution one: strengthen existing buildings.

Solution two: raise earthquake-related awareness. Awareness can help reduce the loss of human lives. This can occur through government-initiated training at various levels: for 'vips', decision-making level administrators, implementation level administrative cadre, educational institutions, and the common person. The media must also play a role in disaster mitigation. Information-based articles and programs are far more constructive than covering post-quake carnage².

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Sources:
1) Geospatial World. 2009. Earthquakes in Delhi: A Capital Problem. Accessed on 14-Jul-2022. Available at: https://www.geospatialworld.net/article/earthquakes-in-delhi-a-capital-problem/
2) Down To Earth. 2001. Delhi is Earthquake Prone. Accessed on 11-Jul-2022. Available at: https://www.downtoearth.org.in/coverage/delhi-is-earthquake-prone-12655