Seismic Zone: Best Way to Know What Your Apartment is designed for Seismicity is defined as the occurrence of frequency of earthquakes in a region. In very simple terms, it is the frequency, distribution and intensity of earthquakes in a region. India being a huge landmass, is very vulnerable to earthquakes. Depending on the severity of earthquakes and risks, India is divided into four seismic zones, where zone 5 is associated with highest level of risk and seismicity and zone 2 is least prone to earthquakes. Zone 5 Zone 5 consists of areas that are most susceptible to earthquakes of high intensity of MSK (MedvedevSponheuer-Karnik) IX. In the map, the regions in red are very high risk zones, and one can see that many regions of Kashmir, some central and western Himalayan regions, the north-eastern regions of India, northern part of Bihar and Rann of Kutch come under very high risk zone. It is good to observe that most of the areas that have basaltic rock or trap rock are highly vulnerable to earthquakes. A zone factor of 0.36 is attached to Zone 5 by the IS (Indian Standards) code; this is crucial as all structural designers consider this factor while designing residential and commercial structures in this area. Needless to mention that maximum precaution and safety measures are included in the structural designs meant for this zone. Zone 4 Zone 4 is a high risk zone that is prone to earthquakes of intensity MSK VIII. The IS code has assigned a factor of 0.24 to Zone 4. The Indian regions that fall in this zone are regions in the Indo-Gangetic plain, Jammu and Kashmir, Delhi, the Faltan or Koyananager area in Maharashtra and the northern regions of Bihar such as Raksual, all fall in Zone 4. Again, since Zone 4 is a high-risk zone, best possible safety measures should be ensured by structural engineers to ensure minimal damage during the time of natural calamity. Zone 3 Zone 3 is moderate risk and the Andaman and Nicobar Islands, some regions of Kashmir and some western parts of Himalayas come under this zone. Zone 3 is liable to MSK VII and 7.8, with a zone factor of 0.16. Zone 2 Zone 2 is the least vulnerable zone which is prone to earthquakes of MSK VI or much lesser intensity. The IS code assigned is very low (0.10).
Do you know what seismic zone your city lies in? Majority of the Indian regions lie in Zone 3, which is a high risk zone with a possible intensity of VII or more. Approximately, 60 per cent of the Indian sub-continent is vulnerable to mid or high risk earthquakes. The capital of India, New Delhi falls in the high risk zone with a possible intensity of MSK VIII, i.e., in Zone 4. Chennai, which was formerly in Zone 2, has now shifted to Zone 3. Kolkata and Mumbai also lie in Zone 3. Guwahati and Srinagar fall in the Zone 5. Cities such as Bangalore and Hyderabad are in Zone 2. Has your designer designed your apartment with adequate measures? Indian cities and structures are built hastily and none of the Indian cities are completely prepared for earthquakes, not even the ones that fall in the highest risk zone. While the Bureau of Indian Standards published the ‘Indian Standard Criteria for Earthquake Resistant Design’ in 1962 (which was revised in 2005), there are very few developers and builders in India that follow this design. No wonder that majority of the Indian buildings do not meet the standards specified in the above mentioned publication. These are just guidelines that are not enforced by the government, and hence very few in India pay heed to it. In the event of an earthquake, one of the 38 high-risk prone cities could face a major disaster, especially as most structures are not earthquake resistant in these cities. The best way to protect your family and yourself from the wrath of future earthquakes is to get your house checked for earthquake resistance with a structural engineer. It is most likely, especially if your house is an old one that your house is not earthquake resistant, and a structural engineer can advise you on techniques that can help you strengthen the structure of your home and to protect it from future earthquakes. While the world seismic community has taken heed from the many earthquake experiences, the same cannot be said about India. In India, very few people are interested in seismic studies and earthquake preparedness activities. Hence it becomes more important for developers, builders and home owners in India to ensure that all the new constructions meet the guidelines provided by the government on earthquake resistant homes. Source: CommonFloor.com For Latest Updates on Real Estate Updates, Property News and Cities Infrastructure Developments Visit: http://www.commonfloor.com/guide
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