PARTNERS
SAFETY BY MITIGATION AND DISASTER RISK PREPAREDNESS
समिद्रिप SaMiDRiP
SCHOOL OF PLANNING AND ARCHITECTURE, NEW DELHI
KNOW YOUR EARTHQUAKE RISK
India is a vulnerable country, in varying degrees, to a large number of disasters. More than 58.6 per cent of the total landmass of the country is prone to earthquakes of moderate to very high intensity. The increase in earthquake risk is due to a spurt in developmental activities driven by urbanization, economic development and the globalization of India’s economy. The increase in use of high-technology equipment and tools in manufacturing and service industries has also made them susceptible to disruption due to relatively moderate ground shaking. As a result, loss of human life is not the only determinant of earthquake risk any more. Severe economic losses leading to the collapse of the local or regional economy after an earthquake may have long-term adverse consequences for the entire country.
RISK ZONES FOR EARTHQUAKE
Bureau of Indian Standards [IS-1893 – part – 1: 2002], based on various scientific inputs from a number of agencies including earthquake data supplied by IMD, has grouped the country into four seismic zones viz., Zone-II, -III, -IV and -V. Of these, zone V is rated as the most seismically prone region, while zone II is the least.
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Zone V: Covers the areas liable to seismic intensity IX and above on Modified Mercalli Intensity Scale. This is the most severe seismic zone and is referred here as Very High Damage Risk Zone. 12% of the land area of India falls in Zone V.
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Zone IV: Gives the area liable to MM VIII. This, zone is second in severity to zone V. This is referred here as High Damage Risk Zone. 18% of the land area of India falls in Zone IV.
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Zone III: The associated intensity is MM VII. This is termed here as Moderate Damage Risk Zone. 27% of the land area of India falls in Zone IV.
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Zone II: The probable intensity is MM VI. This zone is referred to as Low Damage Risk Zone. 43% of the land area of India falls in Zone II.
POSSIBLE DAMAGE BY EARTHQUAKE
Earthquakes cause extensive damage to property, roads and bridges, and lead to collapse or destabilization of buildings, causing injuries and loss of life. The aftermath may bring disease, lack of basic necessities, and worsen the economic conditions. Depending upon their location, earthquakes also can cause ground rupture, landslides, avalanches, fires, soil liquifaction and tsunamis.