Earthquakes of High Magnitude Expected in Delhi
As per Bureau of Indian Standards [IS-1893 (Part- 1): 2002], based on the past seismic history, Delhi lies in Zone-IV that has fairly high seismicity where the general occurrence of earthquakes is of 5-6 magnitude and occasionally of higher magnitude. Delhi lies among the high-risk areas.
This was stated by India’s Minister for Science & Technology and Earth Sciences, Dr. Harsh Vardhan in the Rajya Sabha on Thursday.
He stated that a state-of-the-art 16 station Seismic Telemetry System is already in operation by National Centre for Seismology (NCS) to detect and locate earthquakes in and around Delhi.
The data generated by this network is useful in understanding the changing profile of seismicity and seismotectonics of the Region. NCS has also completed the seismic microzonation of Delhi-NCR on 1:10,000 scale that provides additional inputs relating to the effects of the underlying soil in the assessment of damage potential.
These seismic microzonation maps have become useful in land use planning and formulation of site specific design and construction criteria for the buildings and structures towards minimizing the damage to property and loss of life caused by earthquakes.
In a pilot mode, studies have been taken up for Delhi region through rapid visual screening (RVS) of assessing the structural safety of buildings due to existing complex socio cultural and built environment encompassing vide range of dwelling units from non engineered units with traditional skill to the most modern buildings.
Essentially RVS procedure considers different building types that are most commonly found in India.
By imparting professional training to the Engineers of the civic bodies, Delhi Government is enhancing the technical capabilities of field engineering wings to survey potentially weak buildings.
Guidelines for improving Earthquake Resistance of Low Strength Masonry Buildings (IS 13828:1993) that covers the special features of design and construction for improving earthquake resistance of buildings of low-strength masonry are already in force to supplement these efforts.
Guidelines have also been published by the Bureau of Indian Standards (BIS), Building Materials & Technology Promotion Council (BMTPC) and Housing and Urban Development Corporation (HUDCO) etc. for the design and construction of earthquake resistant structures to minimize the loss of life and damage to property caused by earthquakes.
These guidelines are in wide circulation amongst the public and the administrative authorities responsible for the design and construction of earthquake resistant structures in earthquake prone areas.
Ministry of Home Affairs has taken steps to see that all new buildings constructed under various National and State schemes should be made earthquake resistant (as per the Bureau of Indian Standards) in the first instant so that no new additions to the stock of existing unsafe buildings are made.
Central Public Works Department (CPWD) has prepared a Handbook of Siesmic Retrofit of Buildings for existing buildings that do not meet the seismic strength requirement.
