By Asha Ramachandran
The series of earthquakes that had their epicentre in Nepal and felt in the entire northern region of the Indian sub-continent have set off fears in the minds of people as images of a much more severe tremblor in the Himalayan kingdom reminded one of the utter destruction that can be caused.
Climate change, unplanned development and overexploitation have together led the fragile Himalayan mountains to become a region fraught with ecological disasters. There are lessons to be learnt from nature’s warning messages in the form of frequent landslides, deluge and earthquakes.
The ongoing UN Conference of Parties on Climate Change (COP27), taking place at Sharm-el-Sheikh in Egypt from 6-18 November, as indeed most climate conferences, have warned of mighty disasters if nothing is done to mitigate the alarming rise in global temperatures. At few places on our planet Earth is this warning more relevant than in the mighty, yet fragile, Himalayan range of mountains, which has witnessed a phenomenal rise in weather-related calamities.
Region in danger?
There are lessons to be learnt from the Nepal earthquake for the entire Himalayan region and the Indo-Gangetic region in particular. The earthquake that struck Nepal last week is an indication of worse to come, warn experts, who have been predicting high intensity seismic activity in the Himalayan region since the devastating Nepal quake in 2015. In fact, they have been predicting that the Himalayan region is due for an 8+ Richter quake.
The 2015 Nepal quake had raised the question that the whole region was at risk ~ the Pamir Knot, the Hindu Kush and the plains ~ because of the moving of the continental plate. In fact, the risk of earthquake was said to be more on the southern part of the Himalayan range as there has been less damage on the Tibetan plateau.
Fragile topography
The Himalayan Range of mountains, the youngest as well as the tallest in the world, is convexed towards the south and is formed at the convergence of two tectonic plates ~ Eurasian Plate and the Indian Plate. The tectonic plates are moving at a rate of 50-55 mm per year, which causes considerable stress on the rocks, making them susceptible to landslides and earthquakes.
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.
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.
While averting any need to panic, scientists underline 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.
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.
How vulnerable?
A few years back, the 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.
Incidentally, experts aver 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.
In 2019, the 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.
Way forward
Geologists say the earth is bound to get more earthquakes, only we don’t know when. They will affect mountains as well as plains and lots of people live in hazardous areas. However, experts are unanimous in pointing out that separate sets of disaster management methods need to be worked out.
Stating that short-term relief must support long-term vision, they say there is a lot of duplication in information generation and planning for relief measures. A greater coordination and use of local knowledge to respond would be of prime importance. With communication between various agencies being of prime importance in the event of any disaster, including earthquakes, experts agree that there needs to be coordinated information sharing and response mechanisms as well.
Finally, and not the least, role of women and gender-specific policies are important. With most initial response being “gender-blind”, it is known that women have specific needs in terms of shelter, clothing and risk of trafficking, to name a few.
While risk of disasters, including severe earthquakes, cannot be ruled out nor predicted, preparedness is certainly the way forward. Prevention in terms of adequate and appropriate policies, including those to meet development needs, would go a long way in mitigating any adverse impacts.