How Prone Is Delhi To Earthquakes? Three Major Fault Lines Make It Seismically Active, Expert Says

While Delhi and the National Capital Region (NCR) have not experienced any major earthquake so far, the areas are prone to major earthquakes due to their terrain and certain geological factors.

People gathered outside the buildings of Connaught Place, New Delhi, after earthquake tremors were felt due to a 7.3-magnitude earthquake in Nepal, on May 12, 2015. Delhi is prone to earthquakes because it is sitting on three major fault lines, according to an expert.

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In the wake of the devastating earthquake that recently struck Turkey and Syria, people living in countries that fall under high seismic zones have started worrying about the probability of such a disaster hitting their nations. Several regions of India, including Delhi, fall under seismically active zones, due to geological factors.

While Delhi and the National Capital Region (NCR) have not experienced any major earthquake so far, the areas are prone to major earthquakes due to their terrain and certain geological factors. 

Here is what an expert said about how vulnerable Delhi-NCR is to earthquakes.

What are the geological factors which make Delhi prone to earthquakes?

Delhi is prone to earthquakes because it is sitting on three major fault lines. 

“Delhi has a few fault lines. This means there are some junctions of plates, in and around Delhi-NCR. The Delhi-Moradabad fault line is a major fault line. The Mathura fault line and Sohna fault line are the two other major fault lines Delhi is situated on. There are some minor fault lines as well, which make Delhi extremely seismically active. This means that there are chances of earthquakes occurring in this region,” Professor Subhadeep Banerjee, Geotechnical Engineering Division, Department of Civil Engineering, Indian Institute of Technology Madras, told ABP Live. 

“Delhi has an interesting terrain. On one side, Delhi has the offshoot of the Aravalli region, and on the other side, it has the Yamuna floodplains,” Professor Banerjee added.

“On the Yamuna side, which is the eastern part of Delhi, there are very large soil deposits. Theoretically, whenever we say there are large deposits of silky or sandy material, and where the groundwater is at the surface level, which is typically on the bank of a river, the chances of having large damage during earthquakes are higher,” Professor Banerjee explained.

Not only Delhi, but the entire Indo-Gangetic Plain, which is a 700,000-square-kilometre plain including most of northern and eastern India, is vulnerable to earthquakes. 

“This is the case not only for Delhi, but for the entire Indo-Gangetic Plain, which is rich in sediments deposited by the tributaries of the Ganges. At the same time, the Indo-Gangetic Plain is located at the foothills of the Himalayas, which are seismically active. Therefore, the entire Indo-Gangetic Plain, and not only Delhi, is vulnerable to earthquakes. Unfortunately, many major cities are situated on the Indo-Gangetic Plain, also known as the North Indian River Plain. Also, these cities have very high population densities. Due to these reasons, the Indo-Gangetic Plain is called a ‘high-hazard zone’ in geotechnical engineering terms,” Professor Banerjee said.

“Most of the major Indian cities, particularly those located on the banks of major rivers, could be prone to earthquakes,” he added.

Is a major earthquake due for Delhi or any other region of India?

According to Professor Banerjee, it is difficult to predict if a major earthquake is due for Delhi.

“Historically, Delhi has been lucky in terms of earthquakes. On August 29, 1960, a 4.8-magnitude earthquake shook the national capital. The epicentre was along the Delhi-Gurgaon border. The earthquake caused some structural damages. Many earthquakes have occurred in and around Delhi, but major ones have not taken place in the national capital,” Professor Banerjee said.

“It is difficult to say if an earthquake is due, because it is an entirely natural phenomenon. But, we can say that in case a major earthquake occurs in northern India, the risk of damage is higher, due to the geological setting,” he added.

What measures should be taken in advance to be protected from earthquakes in places like Delhi?

The Bureau of Indian Standards (BIS) has a seismic code called IS 1893. It is the Indian Standard Code of Practice for Earthquake Resistant Design and Construction of Buildings. It is mandatory for construction companies in India to follow this code. The code has several subsections. 

This is the first Indian seismic code, and was published in 1962. 

“We already have an earthquake-resistant design that must be followed during the construction of buildings. There is a code for earthquake-resistant design, known as the IS 1893. Another version of the earthquake-resistant design code is coming. Therefore we can say that we are fairly well-equipped against future earthquakes,” Professor Banerjee said.

“The recent earthquake which struck Turkey and Syria was a once-in-a-lifetime event. It is hard to predict if any future earthquake in Delhi will cause major damage. But, the code is now stronger than before, and I am hopeful that this will significantly reduce the chances of casualties in case of a future earthquake,” he added.

The entire country is divided into four seismic zones: Zone II, Zone III, Zone IV and Zone V. Zone II is the least seismically active zone, while Zone V is the most seismically active zone. According to the Union Ministry of Earth Science, about 11 per cent of India’s area lies in Zone V, 18 per cent in zone IV, 30 per cent in Zone III and the remaining in Zone II. 

Some cities of Uttar Pradesh, which fall under the high seismic zone IV, are Bulandshahr, Deoria, Ghaziabad, Gorakhpur, Moradabad and Pilibhit. Delhi also lies in the high seismic zone IV. 

Guwahati, Jorhat, Sadiya and Tezpur in Assam, Imphal in Manipur, and Kohima in Nagaland fall under seismic zone V. 

“The higher the zone number, the more seismically active it is,” Professor Banerjee said.

“The entire Himalayan belt is extremely vulnerable to earthquakes because it falls on the junction between the Eurasian Plate and Indian Plate. The two tectonic plates move relative to each other. That is why, there is a lot of seismic activity in the Himalayan belt. Several regions of northeast India fall under high seismic zones,” Professor Banerjee added.