Living with Earthquakes in cities

On Monday, Delhi experienced a long tremor with a magnitude of 7.5 on Richter scale with the epicenter  in the Hindukush region. The tremors were felt in Northern India, Afghanistan, and Pakistan. The earthquake has reminded planners and policy makers that they must keep Delhi safe from any such future event. The Sendai Framework for Disaster Risk Reduction 2015-2030 was adopted at the Third UN World Conference in Sendai, Japan, on March 18, 2015. The framework was the outcome of stakeholder consultations initiated in March 2012 and inter-governmental negotiations from July 2014 to March 2015, supported by the United Nations Office for Disaster Risk Reduction at the request of the UN General Assembly. From 27 to 29 January 2016, a conference on the role of Science and Technology will be organised in Geneva, Switzerland, which aims to promote the Sendai Framework of Disaster Risk Reduction.

State of the World: Over the last ten years, disasters have continued to take a heavy toll and, as a result, the well-being and safety of persons, communities and countries as a whole have been affected. Over 700 thousand people have lost their lives; over 1.4 million have been injured, and approximately 23 million have been rendered homeless as a result of these disasters. Overall, more than 1.5 billion people have been affected by disasters in various ways, with women, children and people in vulnerable situations disproportionately affected. The total economic loss was more than $1.3 trillion. Also, between 2008 and 2012, 144 million people were displaced by disasters. Moreover, the impact of an earthquake has increased manifold during the last few years. The biggest increase was in countries with a low human development index.

State of India: With 60 per cent of the Indian land mass susceptible to seismic hazard damage (moderate, high and very high zone), the danger levels  in the Himalayan regions in general and mega-cities of India remain very high. This is not only due to the high rate of seismicity but also because of the dense clusters of population, lack of awareness and prevalent poverty. The recent earthquake in Nepal had caused large-scale loss of human life and damage to property. Therefore, it is high time that we give foremost importance to disaster prediction, prevention and mitigation.

Typical Mechanism of Earthquake in Himalayan Zone: About 80 per cent of the world’s seismic energy for shallow earthquakes, as well as most of the energy in intermediate and deep focus earthquake, are released at the plate boundaries. The Himalayan mountain range dramatically demonstrates one of the most visible and spectacular consequences of plate tectonics. This is known as convergent plate motions where the crust is destroyed as one plate dives under another.

Techniques for Earthquake Prediction: Scientists from developed countries have been using satellites data to predict earthquakes. We must also use and explore the viability of Synthetic Aperture Radar (SAR) sensor data. The study has taken into account actual imaging of the earthquake with the help of ERS-1 satellite. Another technique used is the morpho-structured zoning map preparation of an entire country through Geodetic Very Long Baseline Interferometry (VLBI) to estimate the hazard accurately and thereby make adequate warnings possible.

Earthquake Surveillance: This system will help us better understand the location and interaction of seismogenic structures. This will allow us to target in a more proficient way  the routine activities of seismic monitoring. In addition, we will have selection of appropriate seismogenic zones based on regional tectonic, geological and physiographic features and the regional historical seismicity patterns.

Earthquake Mitigation: Particularly Earthquake Insurance:  Earthquake mitigation includes structural and non-structural measures. Structural measures are those that strengthen a building and make it more resistent to earthquake damage. Non-structural measures include household preparedness or make the content of the house less susceptible to damage. This also includes the purchase of earthquake insurance. In India, we have not focused so far on this issue.

Monitoring Epicentre in the East Regularly: Due to the existence of a Fault Zone on the eastern side of the Delhi, activities need to be regularly monitored.

Retrofitting of Old Buildings: It is difficult and expensive to built all new structures in old buildings, so it is important to incorporate safety measures by incorporating pillar support in present buildings by providing with the fire safety measures and suitable protection fittings for expensive items.

Strict implementation of building codes for construction of new houses and buildings: All new houses that are being constructed or will be constructed should follow earthquake resistant Building codes.

Assessment of landscape synthesis for building construction in Trans-Yamuna areas: Land suitability evaluation should be done before construction of high rising buildings and housing complexes particularly in Trans-Yamuna areas. Floodplains, reclaimed waterlogged areas, geologically weak areas should be avoided for the construction of high rising built up structures.

Development of open spaces for safe shelter particularly in Old Delhi, Paharganj, and Karol Bagh: Parks, green tracks, broad roads should be made that could act as refuge zones.

Well-connected network of lifelines and Communication: Telecommunication networks are first to be affected by an earthquake. It is, therefore, very important to provide satellite telephones to the district collectors so that a link with the affected area can be made instantly in the event of a disaster. Mobile hospitals should be installed in threat prone areas.

Underground Urban Facilities more vulnerable: Underground urban facilities like shopping malls are vulnerable and they require special attention.