Dialogue January - March, 2009 , Volume 10 No. 3
Earthquake Risk Management in the North East
N. Vinod Chandra Menon*
Apart from the close proximity to each other and breath taking scenic beauty, another common feature of the states in the North Eastern region is their high degree of risk and vulnerability to high intensity earthquakes. The North Eastern Region has experienced 18 large earthquakes (M>7) during the last hundred years including the great earthquakes of Shillong (1897) and Assam-Tibet border (1950) both with M=8.7. Several small and micro earthquakes have also been recorded frequently in the region. The high seismicity in the North Eastern states is attributed to the collision tectonics between the Indian plate and the Eurasian plate in the north and subduction tectonics along the Indo-Myanmar range (IMR) in the east. It is also observed that the lithospheric subduction at the Himalayan belt ceased during Pliocene time and the current shallow seismic activity is the effect of continental collision. Subduction, on the other hand, is still continuing in the Indo-Myanmar Range, which is reflected in the intermediate to deep focus earthquakes occurring in the region.
The high seismic risk and vulnerability in India can be seen from the fact that 10.9% of itís geographical area falls in the seismic zone V which is vulnerable to very high seismic risk, while 17.3% of itís geographical area falls in seismic zone IV vulnerable to high seismic risk. Together, these two zones cover 28.2 % of Indiaís geographical area. According to the Vulnerability Atlas of India prepared by the Building Materials Technology Promotion Council (BMTPC), 229 districts of India fall within seismic zones IV and V. This Vulnerability Atlas has been prepared based on the past trends of earthquakes in the country and efforts are now under way to prepare a probabilistic seismic hazard map for India, with the help of seismic experts and scientific institutions, to more realistically reflect the seismic risk and vulnerability profile of the country.
Given the high seismic risk as reflected in the vulnerability of 229 districts in 22 states and union territories of India, the Government of India has initiated several pioneering efforts to strengthen the earthquake preparedness in the country through a proposed National Earthquake Risk Mitigation Project (NERMP) which is currently getting finalized. This article provides an overview of some of the measures which are being proposed to address the seismic risk in the North Eastern region.
Construction of All New Structures
The high seismic risk in the North East makes it imperative that all new construction of buildings, public infrastructure, amenities and assets coming up in the region will have to strictly comply with the codal provisions of the National Building Code 2005, relevant earthquake-resistant building codes and other safety codes. The officials responsible for scrutinizing building plans and granting building permissions have to be made aware of the existing standards and codes which have to be followed while carrying out the construction of structures in high and very high risk zones. The grant of bank loans for the construction of any new structures has to be made contingent on the compliance certificate issued by a competent structural engineer that the design of the structure has incorporated the necessary earthquake-resistant features as mandated by the National Building Code 2005, relevant earthquake-resistant building codes and other relevant safety codes.
Review of Safety of Existing Lifeline structures
A large number of existing non-engineered building stock may have been constructed by private builders and masons who may not have the necessary technical skills to construct earthquake-resistant buildings. Even in the case of masonry structures and reinforced cement concrete constructions, it is likely that adequate attention may not have been paid to the structural safety of the buildings to withstand high or very high intensity earthquakes. It is necessary for the district administration to identify critical lifeline infrastructure and public assets and carry out structural safety audit of such structures with the guidance of trained technical personnel. Wherever it is felt that the structures are weak and fragile and cannot withstand high or very high intensity earthquakes, a priority list of such structures has to be drawn up by the district administration and their seismic strengthening and retrofitting taken up with the support of state government resources. NDMA, in collaboration with the state governments, has proposed the selective retrofitting of a few selected district hospitals from the North Eastern states and a few selected schools from selected districts from seismic zones IV and V from the North Eastern states.
Capacity Building of Technical Personnel
The engineers, architects, lead masons and masons engaged in the construction industry will have to be provided with the skills and knowledge on earthquake-resistant construction techniques, structural safety audit of existing critical lifeline structures and seismic strengthening and retrofitting of weak structures. NDMA has initiated the preparation of a National Earthquake Risk Mitigation Project (NERMP) in collaboration with state governments in high and very high risk seismic zones IV and V. Capacity Building of Technical Personnel is one of the most important activities envisaged in this proposed project, by involving the Indian Institute of Technology, Guwahati, selected engineering colleges and architecture colleges, and selected Industrial Training Institutes and Polytechnics in the North Eastern states. The course curriculum has been finalized with the help of technical experts from the IITs and Indian Institute of Architecture. These training programmes, when conducted as a part of the national initiative, will improve the capacity of technical personnel in the construction industry to undertake earthquake-resistant construction in the North Eastern states and to carry out seismic strengthening and retrofitting of critical lifeline structures to enable them to withstand high intensity earthquakes in future.
Public Awareness on Earthquake Risk and Vulnerability
All stakeholders need to have greater awareness on the earthquake
risk and vulnerability in the North Eastern states, as an aware community is better prepared to face earthquakes when they occur and to minimize the loss of lives, injury and loss of assets, property and infrastructure through their conscious actions. NDMA, in collaboration with the state governments and State Disaster Management Authorities, proposes to launch intensive public awareness campaigns on earthquake risk and vulnerability in earthquake-prone areas, using electronic and print media as well as street plays, hoardings, wall paintings, etc. Special campaigns will address youth in educational institutions and children in school going age group to disseminate the public awareness messages among their neighbourhood communities. In the event of the sudden occurrence of an earthquake, the local communities must have the basic skills of search and rescue, evacuation, establishment of temporary shelters, emergency first aid, distribution of relief to the affected households, etc. Village level disaster management task forces have been set up in several villages to carry out tasks like search and rescue, first aid, shelter management, relief coordination, needs & damage assessment, distribution of relief, water & sanitation in the disaster-affected villages, trauma counseling, patrolling, and disposal of dead bodies and animal carcasses, etc. The public awareness campaigns will be supported by other stakeholders like corporate sector, non-governmental organizations, faith-based organizations and community based organizations like mahila mandals, yuvak mandals, self help groups, etc.
Regulation and Enforcement of an Appropriate Techno-Legal Regime
In the developing countries, weak compliance of building codes and town planning byelaws and inadequate attention to enforcement and regulation are resulting in the loss of lives, injuries and loss of property when earthquakes strike. In the developed world, even a high intensity earthquake causes minimal loss of lives and property as the construction of buildings, public infrastructure and amenities in these countries is governed by strict regulations which ensure public safety. Thus, a high intensity earthquake in the United States of America or Japan may not lead to the loss of lives of a large number of people because the compliance with a rigorous techno-legal regime will ensure that few buildings will collapse resulting in low loss of lives. Even in the developing countries, recent earthquakes have shown that while the buildings constructed in strict compliance with earthquake-resistant building codes and other safety regulations have been able to withstand the impact of the earthquakes, poorly constructed buildings in the same neighbourhood have collapsed resulting in loss of lives and destruction of property and assets.
We have often heard the saying: ďEarthquakes donít kill; collapse of buildings does.Ē The enormous loss of lives and injury to people can be minimized by the strict compliance and enforcement of an appropriate techno-legal regime which consists of modified town planning bye-laws, earthquake-resistant building codes and other relevant safety codes, building bye-laws, National Building Code 2005, Development Control Regulations, etc. in the jurisdiction of the Urban Local Bodies and their extension to semi-urban and rural areas under the jurisdiction of various local administration agencies. The rigorous enforcement of a techno-legal regime is a sine-qua-non for the creation of an enabling environment which assures the safety of itís citizens in disaster-prone areas.
Institutional Capacity Development
With the active involvement of the State Governments, the Government of India will strengthen the institutional capacity in the North Eastern region in the field of disaster management. This will include strengthening of the Communication network and network of seismic monitoring stations in the North Eastern region, improving the scientific capability of science and technology institutions, academic, professional and research institutions in the region, incorporation of disaster management in the curricula of educational institutions and professional and vocational institutions, support to research and development initiatives and documentation of coping strategies and good practices and their wide dissemination in earthquake-prone areas.
Improved Emergency Response Capacity in the Region
The Government of India has deployed a well trained and well equipped battalion of the National Disaster Response Force (NDRF) at Guwahati for the North-Eastern states. Specialised teams of this battalion have also carried out familiarization visits in the various North-Eastern states and interacted with state government and district administration officials and conducted community capacity building sessions. State Governments have been advised to establish State Disaster Response Force (SDRF) units from their existing police force and such forces will be trained and equipped with life saving equipments purchased with 10% of the Calamity Relief Fund allocations to the states. The volunteers of the Indian Red Cross Society chapters, Nehru Yuvak Kendra, National Social Service, National Cadet Corps, Home Guards and Civil Defence, etc. will be trained to carry out specific disaster management related tasks to assist the district administration. Elected representatives of the Panachayati Raj Institutions will also be encouraged to play an important leadership role in coordinating the disaster management efforts at the local levels.
The enormous investment outlays for strengthening the road network, rail network and air transport network for the North Eastern region proposed for the Eleventh Five Year Plan period and the development of urban infrastructure and amenities through the Jawaharlal Nehru National Urban Renewal Mission (JNNURM) projects and the proposed new public infrastructure and amenities in the region will have to be designed with special attention to the earthquake risk and vulnerability in the region. Simultaneously, there is a greater need to strengthen the medical preparedness and mass casualty management facilities in the region by planning the procurement of helicopter ambulances, containerized mobile field hospitals and integrated ambulance network. The public awareness on earthquake risk and vulnerability will become the foundation for an enlightened multi-stakeholder initiative to launch a concerted attempt to usher in a culture of preparedness, mitigation and improved emergency response in the North Eastern Region. The National Disaster Management Authority of the Government of India and the North East Council will work in close cooperation with the Ministries and Departments of the Government of India and the state governments of the North Eastern states to work towards the vision for a ďDisaster Resilient North East ď which puts the safety of itís citizens, disaster-resistant capability of the critical infrastructure, public amenities and assets as well as improved community resilience among disaster-prone communities as itís foremost objectives.
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