Broken houses after earthquake in Nepal

On shaky terrain

Delhi’ites are not new to earthquakes as the city lies in a seismic zone. But the recent series of minor tremors, coming as they are at a time when the world is grappling with a rapidly spreading Coronavirus outbreak, is sending strong signals to the citizens and authorities alike to heed the oft-repeated calls to earthquake proof India’s Capital city.

It was on 8 June 2020, when Delhi and NCR (National Capital Region) experienced the region’s 13th low-intensity earthquake in the past two months. With a magnitude of 2.1, it was not so strong but the quake made people step out of their homes. Just a week back, on 3 June, the Indian Capital witnessed another low-intensity tremor with its epicentre reported to be around 19 km south-east of the satellite city of Noida.

 The series of earthquakes in the Capital has created a fear in the minds of Delhi’ites, who are already facing a harrowing time due to the Coronavirus (Covid-19) outbreak. Haunted by a rising number of Corona cases and death toll doubling every other day, these weekly earthquakes are only adding to their woes.  These frequent minor earthquakes have also fueled a speculation of a bigger tremblor very soon. However, scientists have rubbished these claims citing that earthquakes cannot be predicted and the seismic activity could be a normal phenomenon. But one should not forget that Delhi falls in Seismic Zone 4, which means it is very prone to earthquakes. In simple words, the region may face mild to strong tremors any time. But the big question remains: Is Delhi prepared to tackle a big shock?

 Of course not, most experts opine. As per architects, 90 per cent buildings in the Capital are unsafe and a magnitude 7 or above will lead to huge losses.  One should not forget what happened in neighbouring country Nepal in April, 2015, when a high intensity tremor almost wrecked the entire city of Kathamandu and its all landmark tourist destinations. The January 2010 earthquake in Haiti killed an estimated 230,000 people, injured 300,000 and displaced 1.5 million from their homes.  Perhaps these figures should put the authorities on high alert as an earthquake is certainly much more dangerous than Covid-19.

How earthquakes occur?

Earthquakes are caused by the movement of tectonic plates. Based on the frequency and intensity of tremors, a seismic zoning map is drawn up, dividing an area or country into various seismic zones. The Indian subcontinent is divided into four seismic zones (II, III, IV and V) based on scientific inputs relating to seismicity, earthquakes that occurred in the past and tectonic setup of the region. The Bureau of Indian Standards is the official agency for publishing the seismic hazard maps and codes. From the high-intensity Zone V to low intensity Zone II, the zonings in the country have been decided on the basis of the number of active fault lines (joint or juncture) on the earth’s surface, which may or may not become the epicentre of an earthquake in future.

 Now the main reason behind earthquakes in the Himalayas and adjoining areas has always been the friction between the Indian plate and the Eurasian plate. The Himalayan region, extending from the Hindu Kush to the North-East and going south to Southeast Asia, is seismically one of the most active regions in the world. And it has experienced several big earthquakes in the past, the most recently in 2015 in Nepal.

Where Delhi stands

As Delhi finds itself in Seismic Zone IV, it has every reason to take the recent tremors seriously. However, scientists are divided on comprehending these series of shocks in Delhi: Many say small intensity earthquakes are a sign of a major jolt while some claim that small intensity will reducing the chances of a major earthquake.  Professor Chandan Ghosh of the civil engineering department of IIT Jammu told Jagran News that Delhi falls in a sensitive region and close to the Himalayas, which was formed by the collision between the Indian tectonic plate and the Eurasian tectonic plate. The world’s highest mountain range, which began 50 million years ago, continues to rise even today. Therefore, areas like Delhi-NCR, Kanpur and Lucknow are the most prone to earthquakes and possibility of a major earthquake can’t be ruled out.

 However, director of the National Centre for Seismology (NCS), Dr B K Bansal, has said there is no need to panic with respect to the recent seismic activities in Delhi-NCR region. “Given the seismic history of Delhi and its vicinity, the occurrence of minor earthquakes in Delhi-NCR is not unusual,” he said. However, he also underlined that it is important to undertake preparedness and mitigation measures to reduce the earthquake risk. Therefore, Delhi will have to prepare itself any impending earthquakes.

  The current series of quakes are similar to the one that took place on 27 August, 1960. With its epicentre between Delhi Cantonment and Gurgaon, the tremor was shallow and its magnitude was 4.8. Though the Capital city and its surrounding region have experienced earthquakes since ancient times, records exist from 1720 A.D. only. Major earthquakes were reported near Mathura on 1 September, 1803, and near Bulandshahr on 10 October, 1956. A magnitude 4.0 tremblor on 28 July, 1994 was said to damaged the minarets of Juma Masjid. Delhi also experienced two small earthquakes of local origin in 2001, on 28 February and 28 April, of magnitude 4 and 3.8 respectively.

Is Delhi vulnerable?

The reecent earthquakes are occurring due to fault lines present in Delhi-NCR. A few years back, Centre for Science and Environment came up with a report stating that “earthquakes don’t kill, buildings do”. It also mentioned that the condition and quality of Indian building stock is poor when it comes to seismic performance. Many a time, buildings have collapsed even without an earthquake, claiming many lives. In Delhi’s case, the situation is worse as it has developed in a very clumsy manner, with a lot of illegal constructions and dense colonies. But the irony is that the majority of Delhi’s population lives in these colonies. Moreover, Delhi is home to several ancient structures as well as modern high-rise buildings, which further complicates the matter.  Therefore, if something untoward were to happen, it would cost a lot of lives and properties.

 One should not forget the Bhuj earthquake that measured 6 on the Richter scale but devastated the entire region. Thus, these frequent earthquakes are a kind of warning to Delhi to strengthen its buildings in order to face any big shock. “Years ago anti-earthquake construction techniques were not available. Hence these techniques could not be used in the buildings and bridges that were built then. But now that this danger is increasing and we have such techniques, then there should be an initiative in this direction and people should adopt these techniques in sensitive areas to make their houses safe and earthquake resistant,” said Chandan Ghosh.

 Incidentally, experts avert that there is no such thing as “earthquake-proof” buildings, only “earthquake resilient” since no structure can be completely immune to damage from tremblors. These are buildings or structures designed to withstand strong tremors without collapsing and preventing loss of life. Japan, which is prone to frequent and severe earthquakes, is particularly known for its traditional as well as modern high-rise buildings that are quake resilient. They are flexible and are said to move with the shaking earth but do not collapse.

 In India’s North-East, which is a highly seismic area, traditional buildings are made of bamboo with mud plaster. This makes them flexible and so are safe during even strong quakes. Some modern building designs have borrowed this concept and use flexible steel structures.

Capital infrastructure

Delhi is situated on top of three active seismic fault lines though as many as 20 fault lines mapped across the city. These are, Sohna fault line, Mathura fault line and Delhi-Moradabad fault line and Delhi-Moradabad fault line. Gurgaon is located on seven fault lines, making it the most seismic area in Delhi-NCR.
 India had introduced rules for building construction way back in 1893. The guidelines included design elements to absorb shocks in case of any tremor. Over time, a few changes were made and the Union government came up with norms known as National Building Code 2005. Unfortunately, these norms are not followed properly in construction, of mainly residential buildings, leaving the citizens in imminent danger.

 This is not scenario unique to Delhi, but prevalent all over the country, though it does not take away the responsibility from the authorities. This accounts for news of heavy casualties whenever any earthquake takes place in any part of country or the world. However, there are no lessons learnt and a few days later, the news fades from memory and news channels.

 In 2019,  Delhi High Court had directed Delhi government to set up a committee to monitor buildings as per the directed norms. It mandated safety audit of every building, whether in a regular colony or an illegal colony. Once more, any action seems to take place on paper only and not on ground. Therefore, the High Court recently snubbed the Delhi authority once again that mere paperwork and consultations would not solve the imminent threat related to earthquakes and some work on the ground level needs to be undertaken. “It goes without saying that mere paperwork and consultations would not solve the imminent threat that the citizens of NCT of Delhi face due to heightened seismic activity and that it is only actual work on ground which would come to rescue of the citizens,” the court said.

 One may, therefore, infer and concur with the honorable court that these frequent earthquakes, minor though they may be, are perhaps a warning to the people of Delhi and the city’s administration to buckle up. Otherwise the consequence may well be catastrophic.

Earthquakes in the past few days in Delhi-NCR

8 June – 2.1 Richter Scale – Noida

3 June – 3.2 Richter Scale – Faridabad

1 June – 3 Richter Scale- Rohtak

1 June – 1.8 Richter Scale- Rohtak

May 29- 2.9 Richter Scale- Rohtak

May 29- 4.5 Richter Scale- Rohtak

15 May – 2.2 Richter Scale- New Delhi

10 May – 3.4 Richter Scale- Delhi

06 May – 2.3 Richter Scale- Faridabad

03 May – 3.0 Richter Scale- Delhi

16 April – 2.0 Richter Scale- Delhi

13 April – 2.7 Richter Scale- Delhi

12 April – 3.5 Richter Scale- Delhi

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