Every year, natural disasters result in enormous loss of life, and set back economic and social development by years, if not decades. Natural disaster cannot be prevented; however, they can be managed better with focus on overlapping phases of mitigation, preparedness, response, and recovery. Science & Technology driven knowledge-based information infrastructure is required to provide balanced support to each phase of these activities in the Disaster Management cycle. Broadly this approach by the NDMA calls for, inter-alia, development of essential scientific and technological infrastructure, some of which are outlined hereunder.

Vulnerability Analysis and Risk Assessment (VA&RA)

The policy of the NDMA has been to move away from the response-centric approach to proactive and holistic Disaster Management in the country, the single most important scientific tool that needs to be deployed is the “Vulnerability Analysis and Risk Assessment” (VA&RA) of the people, the habitats and the infrastructure in different parts of the country with respect to various natural hazards.The level of mitigation and preparedness programmes are to be decided by the DM authorities on the basis of the level  of  protection aimed for (e.g. lifeline/vital infrastructure, will  have to survive the worst possible hazard impact and hence enhanced level of protection is called for) and the mitigation resources that can be mobilized.Centered around two parameters viz the demand for inherent hazard resisting capacity of  the buildings/infrastructure from the hazard profiles (i.e. the damaging forces) and their actual capacity to withstand the same, vulnerability analysis and risk assessment involves estimation of the probability for five different damage patterns (nil, slight, moderate, extensive and complete). The damages so arrived at are then converted to economic losses and human causalities (in terms of different types of injuries) by using mathematical models. The powerful VA&RA tool, would enable DM Stakeholders for holistic management of disasters by way of identifying and prioritizing (i) all mitigation tasks/projects; (ii) adaptation  of appropriate rehabilitation and reconstruction work, including retrofitting of important structures;  (iii)  enforcement of building construction codes;  (iv)  planning for future land-use  to minimize/eliminate unnecessary construction costs for new buildings/infrastructure; (v) design of underground lifeline infrastructure. (vi)  decision on location of all essential inputs for rescue and relief operation, training centres, DM resource centres, shelters, relief centres, medical facilities etc as per vulnerability profiles (instead of an adhoc decision). However, the development of this scientific tool will be enabled through the availability of some technical inputs.

Digital Maps of India at Required Scales and Contour Intervals.

Digital Base Maps at appropriate scale and contour intervals (required for managing flood and landslide hazards) of the Indian landmass are essential for development of Geographical Information System (GIS)-platform (prepared by over-laying on such maps, the other information like demographic, landuse, habitats, infrastructure, hazard profile etc) which is crucial for management of all hazards. NDMA has taken up the preparation of Digital maps for all the assessed 312 Multi Hazard Prone (MHP) districts on priority.

Preparation of Upgraded Hazard Maps initially for Multi-Hazard Prone districts.

For proper management of disasters, there is an urgent need for identifying scientifically the list of hazard-prone districts (with reference to earthquake, landslide, flood and cyclone) in terms of intensity, frequency of occurrence, and duration of the hazards in addition to the area affected. The upgraded list of earthquake and landslide hazard-prone districts has already been finalized by an expert committee constituted by the NDMA. A similar list for cyclone hazard has also been approved by the committee and the confirmation of the same with the archive data of the India Meteorological Department (IMD), New Delhi is expected soon.

Probabilistic Seismic Hazard Analysis (PSHA) for Seismic Microzonation Earthquakes are low probability events but with high level of risk to the society. 

Hence, either underestimation or overestimation of seismic hazard would prove costly in the long run. In addition to the importance of realistic seismic microzonation in urban planning, construction of new structures and retrofitting of existing building/infrastructure, it is equally important (i) to the professionals for their decision on the extent of detailed geotechnical investigation to be undertaken, depending upon the nature of the building/infrastructure proposed in the specified microzone, (ii)  for enforcement of building construction codes and above all (iii) for optimized use of resources available.

Probabilistic Seismic Hazard Analysis (PSHA) at the bedrock level of the Indian land mass takes into account the probability of exceedance of the ground motion against which the structures should be designed. In this approach, each broad region is sub-divided into a number of microzones or grids of about 25km X 25km size and the values of PGA and Sa at the nodes of each microzones are evaluated (with corresponding return period exceedance).For seismic microzonation, PSHA is subsequently coupled with geotechnical investigations (to take care of the ground amplification of the rock level ground preparation of the rock level acceleration due to site-effect). These PSHA studies will be completed within next one year after which pilot studies of two cities will be carried out.