'City is at very high risk'

Experts say danger in the city is magnified by its high density of population

Delhi is in zone IV. It is not as bad as zone V. But the difficulty is, it’s not just about the magnitude of earthquake. Our own houses can kill us,” says Jamia Millia Islamia Vice Chancellor Prof Talat Ahmad. 

Ahmad is a renowned geologist who believes that houses in Delhi are not quake-proof, despite the city being in the zone that can  witness a high intensity quake. An earthquake with a magnitude of 6 or more on the Richter scale can put 50 per cent of residential buildings in Delhi at risk, says another geologist C S Dubey. 

As per the Bureau of Indian Standards publication, Delhi falls in seismic zone IV. So an earthquake of a magnitude from 6.0 to 6.5 on the Richter scale can come anytime in and around Delhi. 

“The Nepal earthquake of magnitude 7.9, whose epicentre is more than 700 km away from Delhi, shook NCR approximately equal to the earthquake event having intensity of 5 magnitude,” says Dubey, explaining the impact of quake in the Himalayan region. 

If there is an earthquake around Delhi, most likely it will be associated with a major geological structure known as the Delhi-Hardwar Ridge. 

“It’s one of the ridges where there could be some tremors,” says Ahmad. But nothing can be predicted accurately. Quake experts claim that big earthquakes can occur anywhere in the Himalayan range. 

“If the Nepal like earthquake occurs in seismic gap areas of the Central Himalayas, that is 200-250 km away from Delhi, then the intensity of the event will be maximum (more than 5 on the Richter scale) and the city may be highly vulnerable,” the Delhi University professor, Dubey, says. 

The city will be highly susceptible because of high density population and concentration of buildings, explains Ahmad. Talking about how fragile the situation can get in Delhi, he quips that even a high intensity earthquake in a low population area like the US state of Alaska will not be devastating. 

“The recent quake had its epicentre 70 kms away from Kathmandu. But most of the people died in Kathmandu because of high concentration of population and buildings,” he says. 

The entire North India felt tremors when the devastating quake occurred in Nepal. It has triggered a debate on vulnerability of Delhi. 

“An earthquake of 6.7 magnitude reportedly occurred in 1720. Many research works that presumed an epicentre close to Lal Quila near Yamuna on Delhi-Sargodha fault found that it could have been a disaster,” says Dubey. 

“We are making huge structures like Akshardham which is sitting on a floodplain. It also has buildings of Sports Authority,” says the Jamia VC. “These structures are sitting on soil which is very soft.” 

He says there should be a micro-mapping of vulnerable areas in Delhi for better earthquake preparedness. 

Much of Delhi does not follow the quake-proof building norms. The unauthorised colonies in the city, which have mushroomed only recently, are made from concrete structures that are not sturdy enough to withstand earthquakes. 

Old Delhi areas with their narrow lanes and cramped buildings are not even open to emergency services like fire brigade, says Ahmad. 

He bemoans that nothing much can be done about the buildings that stand tall without following followed earthquake-related building norms. 

“The least we can do is to identify the vulnerable areas for a better disaster management response. Vital buildings like schools, hospitals, government buildings which are not compliant with the building code should be identified, and corrective measures should be taken after that,” he says. 

The Indo-Gangetic plain, where many of the densely populated cities of North India lie, is highly earthquake prone. 

Ahmad says he has written to the Minister of Earth Sciences Harsh Vardhan, asking him to invest resources in micro-mapping the vulnerable spots before an impending earthquake rocks the region. 

Roger Bilham who studied tectonic plate movements in the Himalayas has given a forecast of a 9 Richter scale earthquake. 

“This is likely to occur in near future, anywhere in the western Himalayas. This can happen in two years or in next 100 years,” Ahmad says.