By How vulnerable is India to the earthquake?
Several earthquakes in the recent past remind us of the high level of seismic hazard and risk prevailing in the country. About 59% of India’s land area is under the threat of moderate to severe earthquake shaking intensity VII and higher. During the last two decades, seven major earthquakes have resulted in over 24,000 deaths in our country. The regions far away from the Himalayas and other inter-plate boundaries, which were once considered to be relatively safe from strong shaking, have also experienced several devastating earthquakes. The huge losses of life and property in the earthquake-prone areas of the country have shown that the built environment is extremely fragile, and our ability to respond to these events is extremely inadequate. It has been found that the casualties were caused primarily due to the collapse of buildings that usually have no earthquake-resistant features. This emphasizes the need for strict compliance with town planning bye-laws and earthquake-resistant building codes in India.
What are the effects of built structure collapse during an earthquake?
The building collapse results in the widespread loss of lives and property including lifeline infrastructure like roads, dams, and bridges, hospitals as well as public utilities like power and water supply installations. Past earthquakes have shown that over 50 percent of the lives lost were due to the collapse of buildings that were not earthquake-resistant. Though there is a number of earthquake-resistant design codes and other regulations available but proper implementation of these urgently requires serious attention as it’s the collapse of buildings and other structures that kills.
What is India’s position in earthquake-resistant construction measures?
India has advanced considerably in developing earthquake-resistant codes of practice and guidelines for constructing RCC and steel framed buildings, brick or stone masonry buildings, and a combination of clay, wood, bamboo, and thatched houses. Yet the high level of earthquake risk in our country’s context is mostly attributed to unplanned and ill-planned urban infrastructure developments. In order to reduce vulnerability, it is important to create proper awareness about earthquake-induced damages and their mitigation measures.
How reliable is earthquake prediction-related research?
There are several schools of scientists across the globe who are chasing at-least one reliable prediction criterion among 35 plus precursors being measured and analyzed. Some earthquakes in the past gave reliable foreshocks and many did not. In case of the Haicheng earthquake (magnitude M 7.3, February 4, 1975) in China several foreshocks for more than a month were noted by the scientists that finally led to the successful prediction of the final (bigger) jolt. But, the 1976 Tangshan earthquake (M 7.6) on 28 July 1976, in China gave no foreshocks, killing 242000 and damaging eighty-five percent of the buildings, bridges, railways seriously. After, Kobe (1995) in Japan killed more than 6000 people, more emphasis on early warning i.e., catching the earthquake shear wave a few seconds after it’s occurrence is given worldwide acceptance. Several countries have evolved EWS in place and in India, IIT-Roorkee has installed a similar system for the state of Uttarakhand. Is it true that too many recent earthquakes in Delhi-NCR indicate the occurrence of high- impact earthquakes in near future? There is no definite answer to this till we are able to map the seismic activities of fault lines in and around Delhi-NCR, including the distant earthquakes taking place in the Himalayas.
Currently, National Centre for Seismology, Delhi, under the Ministry of Earth Sciences, provides earthquake information based on the seismometer
recordings soon after the earthquake event happens. At the moment, in Delhi-NCR, scientific studies are in place to simulate or correlate fault line movement, deformation, ground vibration, building response, etc. with the current records of the earthquake event. We are yet to achieve the goal as it needs enormous temperament for the leading scientists vis-à-vis quality instrumentation as well as rational judgmental power among the geoscientists. So, whether several earthquakes in Delhi would lead to a bigger or smaller one or not is difficult to say either. However, there is the possibility of bigger earthquakes if fault movement is eventually packing up their relative dispositions, which may lead to accumulating more strain energy or vice versa. Till active fault movements are characterized, mere speculation about the future course of activation bears no significance. But we can’t just wait and see for that speculation coming true or otherwise. Basic purpose would be getting ready for the bigger shocks and making all the constructed facilities earthquake resilient through systematic training and capacity building as well as following the expert building professional advice.
Are the buildings in Delhi resilient to earthquakes?
Buildings in Delhi are very complex in nature and the majority do not follow proper construction measures mentioned in the building code devised by the Bureau of Indian Standards since 1962. More so, Delhi-NCR is subjected to local earthquakes that have a more damaging impact on low-story buildings and distant ones from the Himalayas that have a potentially damaging impact on multistory buildings. The structural performance of buildings due to local and distant earthquakes is way behind the provisions and understanding of the experts as of date. The combined responsibility of the experts and noncompliance with the building code has been an issue yet to be taken up by the people at large and the system in particular. Municipal Corporation of Delhi (MCD) sanctions building PLANs as per set guidelines for the areas where constructions are authorized. There are no set rules that are being followed for the areas where unauthorized constructions e.g. urban villages being inducted into MCD’s jurisdictions. More so, there is no check on the construction quality on the Ground; resulting in these buildings having no bindings on the application of Building codes. Many states and municipalities in the country, have made bye-laws in favor of the mandatory application of the building codes. But site-specific inspections are not rationally framed by the authorities. NDMA made several specific guidelines on Earthquake Management (2007) along with a route map for
time-bound actions, identifying building typologies in the country, retrofitting buildings, etc. The status as of today is far from the goal to be achieved.
Delhi Govt. took several initiatives, e.g. retrofitting five buildings in 2005; making a list of expert engineers for scrutinizing structural safety; to name a few. However, it is to be realized that every citizen living in an earthquake- prone area is to consult experts, which is simply the same as we look for the best and most reliable medical doctor for serious medical issues. Therefore, the impact of earthquakes on our setup is already a serious issue. So let’s not just compromise with the quality constructions as long as the next big shock hit us hard.
The construction fraternity comprising of real estate agencies, contractors, builders, architects, planners, building owners, construction material suppliers, Civil engineers (having expertise in earthquake-resistant design & implementation), municipal authorities, community, and organizations like DDA, MCD, PWD, DUAC, Delhi Fire Services, Police etc. have to work in synergy to ensure/enforce National Building Code-2016.
Any comment on the earthquake-resilient construction in India?
We have to look forward to establishing the necessary techno-legal and techno-financial mechanisms in order to ensure that all stakeholders like owners, builders, architects, engineers and government departments, responsible for regulation and enforcement adopt earthquake-safe construction measures in all design and construction activities.
The main focus shall be:
- Earthquake-resistant design and rehabilitation of structures
- Indian standards and guidelines on earthquake technology
- Seismic evaluations and retrofitting of selected lifeline buildings
- Disaster-safe construction practices and issues
- Techno-legal and techno-financial framework for earthquake protection compliance
- Training and Capacity building of masons, architects, and engineers
- The strengthening of all building development and regulating agencies with the right level of professional human resources to deal with proactive responses needed by the building professionals and builders.
The professional human resource pooling for contiguously situated human settlements and the related regulating agencies should be attempted, considering the socio-economic and budgetary constraints of smaller-level local bodies dealing with building regulation work. In order to make built infrastructures disaster resilient, it is recommended that the governments and all local bodies (urban & rural), development authorities, special and new town development agencies, etc. need to modify, revise, revamp the existing building byelaws; development control rules; planning standards; town planning rules; special regulations for fire, structural, health, construction, electric and life safety, in line with the NBC-2016 by suitably adopting fully or adapting it with local variation as may be needed.
NBC-2016 needs to be adopted as the basis for all structural design, fire protection, building and plumbing services, building materials and construction practices (and construction safety) and for proper protection, upkeep & maintenance of water bodies by modifying the departmental construction codes/ specifications/manuals of Govt. construction departments.
