Shaky foundation
earthquake-resistant measures adopted by India may be founded on shaky ground as the country has failed to incorporate the latest understanding of geophysical processes, caution experts.
Seismologist K N Khattri, who recently retired as head of the seismology department at the Indian Institute of Technology in Roorkee, questions the soundness of the seismic zoning map of India, which is used as the basis for construction codes in seismic areas. Writing in the March 10 issue of Current Science (Vol 90, No 5), Khattri said that the map looked particularly patchy for the Himalayan region, which has experienced several strong earthquakes.
According to the seismic map, last updated in 2002, the Himalayan region has only a "few' islands of high seismicity (categorised as zone v), with the remaining areas categorised as zone iv , the next lower risk range. "While regions close to epicentres of previous large earthquakes in the Himalaya are shown as having the highest risk, the adjacent areas along the range are shown with lesser risk