Delhi is one of the most populated cities prone to earthquakes in India — can it handle what Turkey couldn't

There's a famous saying — "earthquakes don't kill people but buildings do!" And that's what has marred Turkey and Syria. A powerful quake in these two countries on Monday damaged over 5,700 building, leaving more than 5,000 dead, thousands homeless, several orphaned and many still trapped beneath the rubble.

People in India, especially Delhi — which is among the most populated cities prone to earthquakes in the country — must have been wondering what would have happened if such a strong earthquake had jolted their region. Is Delhi prepared to deal with such a disaster? Well, if the buildings in the city are earthquake-resistant, the situation wouldn't probably turn catastrophic, as it happened in Turkey and Syria.

Delhi lies among the high-risk zones. "Delhi is located in zone IV which has fairly high seismicity where the general occurrence of earthquakes is of 5-6 magnitude, a few of magnitude 6-7 and occasionally of 7-8 magnitude," the city government's District Disaster Management Authority (DDMA) said.

Moreover, due to its peculiar geological setting, Delhi could also sustain strong shaking due to a large earthquake in the Himalayas.

Deben Moza, Senior Executive Director, Head of Project Management Services, Knight Frank India said, "There's one school of thought where experts believe that if we have an earthquake of (magnitude) 7 and above, we could see the destruction that we saw in Turkey."

Several regions in India are classified into four seismic zones — Zone V is seismically the most active region, while zone II is the least. "Approximately 11 percent area of the country falls in zone V, approximately 18 percent in zone IV, around 30 percent in zone III and remaining in zone II," Jitendra Singh, the Minister of State (Independent Charge) for the Ministry of Science and Technology and Earth Sciences, had told the Lok Sabha in 2022.

"Earthquake disaster in Delhi has the potential to go well beyond the statistics of deaths and injuries," the city government says in a document last updated on October 23, 2022. It notes that such disasters in the national capital "will have huge economic and political implications", which might affect the entire country and not just Delhiites.

In 2019, India Today reported that the Municipal Corporation of Delhi (MCD) and some earthquake researchers believe that approximately 90 percent of the buildings in Delhi are at risk during a strong earthquake incident.

Most buildings in Delhi might not meet Indian standards on aseismic constructions and might be considered deficient from a seismic safety viewpoint, the DDMA says, adding that "pockets with high-rise buildings or ill-designed high-risk areas exist without specific consideration of earthquake resistance."

This might be because there is no legal framework to require that all constructions in Delhi must implement seismic code provisions, it adds. "The result is that most buildings in Delhi may not meet code requirements on seismic resistance," it said.

Although, the first code of practice for earthquake-resistant design was developed in India as early as the 1930s after the 1935 Quetta earthquake and the Bureau of Indian Standards developed its first code on aseismic design in 1962.

The government said the problem is likely to persist even if somehow authorities start ensuring that all new construction is earthquake resistant. "There still will remain a very large inventory of old buildings that will be deficient for seismic safety," it says.

The National Disaster Management Authority and the Bureau of Indian Standards released "Simplified Guidelines for Earthquake Safety of Buildings from National Building Code of India 2016", which was expected to guide current and potential homeowners towards reducing losses.

Other than this, 'Indian Standards for Earthquake Resistant Design and Construction of Buildings—code of Practice' was released by the Bureau of Indian Standards.

"Till couple of decades back, the buildings in Delhi were designed as per zone IV codes but now they are designed as per zone V codes to withstand high intensity earthquakes," Moza told CNBCTV18.com.

Moza highlighted other major issues that make buildings in Old Delhi and even in newly-built colonies weak. "Old Delhi is congested and unplanned...the buildings there have outlived their age...Even in the built-up colonies...for example, the problem in Dwarka is that the groundwater is very saline which impacts the structure of the buildings.

He added that even if the construction is designed as per the code, in a lot of buildings in housing societies, the strength of building are getting weaker day by day because of the construction material and water being used.

Normally, the life expectancy of a building is 50 years, he said, adding that because of the water quality and poor construction material, it is reduced by half. He further mentioned that if a structure is designed keeping in view the recommended code, one needs to ensure that these are implemented in the construction process.

"Because of our unplanned, unstructured, and poorly constructed building designs, our infrastructure could not withstand these earthquakes," said Jyotima Kanaujia, a seismologist.

"It is necessary to simulate the risk scenarios for Delhi and take steps to mitigate losses to lives and property," said Jyotima Kanaujia, a seismologist, said.

The problem must first be recognised and quantified, the government says. It adds that authorities need to develop a "rational seismic retrofitting" policy, first for government-owned buildings and then for private constructions.

"We must focus our attention to the institutional and manpower development at all levels," it says while emphasising the importance of "extensive studies needed for seismic hazard evaluation for different parts of Delhi and vulnerability assessment for different kinds of constructions."

There's also a need to develop manuals outlining methodologies for new constructions and retrofitting old ones.

Zone V: Parts of Jammu and Kashmir (Kashmir valley), the western part of Himachal Pradesh, eastern part of Uttarakhand, Rann of Kutch in Gujarat, part of Northern Bihar, all north-eastern states of India and Andaman & Nicobar Islands

Zone IV: Remaining parts of Jammu & Kashmir, Ladakh, remaining parts of Himachal Pradesh and Uttarakhand, Some parts of Haryana, parts of Punjab, Delhi, Sikkim, the northern part of Uttar Pradesh, small portions of Bihar and West Bengal, parts of Gujarat and small portions of Maharashtra near the west coast and small part of western Rajasthan

Zone III: Kerala, Goa, Lakshadweep islands, some parts of Uttar Pradesh and Haryana, remaining parts of Gujarat and Punjab, some parts of West Bengal, part of western Rajasthan, part of Madhya Pradesh, remaining part of Bihar, northern parts of Jharkhand and Chhattisgarh, parts of Maharashtra, parts of Odisha, parts of Andhra Pradesh and Telangana, parts of Tamil Nadu and Karnataka.

Zone II: Remaining parts of Rajasthan and Haryana, remaining parts of Madhya Pradesh and Maharashtra, remaining parts of Odisha and Andhra Pradesh, remaining parts of Telangana and Karnataka, remaining parts of Tamil Nadu.