India, under whose soil lie three major seismic faults, took a modest step by issuing a new ISI code for quake-proof materials and designs, particularly high-rise buildings and public structures several years ago. But these measures have so far failed to make the situation any better, as there is no mechanism to enforce their use in construction. This suited builders and contractors well, as conventional materials and designs cost five to 10 per cent less than those made to withstand a tremor.

This decade saw at least four major earthquakes jolting different parts of the country, the latest being the one that occurred on the midnight of March 28 in Chamoli and nearby areas. The Chamoli earthquake, in which more than 100 people were killed and several hundred people injured, was the second major earthquake in less than two years. In May 1997, a tremor hit parts of Jabalpur in Madhya Pradesh killing about 25 people and damaging properties worth several crores of rupees. The other two quakes -- the 1991 Uttarkashi and the 1993 Latur tremors -- were much more severe in nature and together resulted in the death of more than 14,000 people and razed tens of thousands of houses, rendering innumerable people homeless. If one takes the partial damage cause to more than 2.5 lakh dwellings also into account, the economic loss was astronomical. The damage would have been much more calamitous if major cities and towns, which are not far off from epicentres of these quakes, were disturbed.

It has been conclusively proven that there are many seismically active regions in the country. The major ones are the Great Himalayan region where the Eurasian plate reportedly meets the Indian subcontinent, the Indo-Gangetic plains dotted by many river rift valleys and the Indian peninsular or the Indian shield. In the span of the last 100 years, earthquakes have occurred only in the Himalayan region. The 1897 Assam tremor, the worst-ever earthquake recorded in recent history, with a magnitude of 8.7 on the Richter scale, occurred in this region.

Though the Chamoli earthquake (6.8 on Richter scale) was stronger than the 1991 Uttarkashi one (6.6 on Richter scale), the toll in the recent tremor was at least less than one-twentieth of the latter one. It caused less damage perhaps because the depth of its focus was comparatively lower. According to Dr V P Thakur, director of the Wadia Institute of Himalayan Geology at Dehra Dun, the Chamoli quake was estimated to be at 30-33 kilometre depth, compared to the Uttarkashi quake which was about 15 km deep.

Scientists say there are two main seismic belts emerging in north India. One runs in the outer Himalayas, which has witnessed two major quakes -- in Kangra in 1905 and along Bihar-Nepal border in 1936. The second is the inner belt that runs from Nepal via Garhwal to Himachal Pradesh in north-west direction, at the junction of the lower and higher Himalayas. Chamoli lies in the second region, along with Uttarkashi.

Both zones are active currently. Says S N Bhattacharyya, seismologist at the India Meteorological Department (IMD), in New Delhi, Garhwal area has experienced eight earthquakes of a magnitude of 6 or more on the Richter scale in the last 120-125 years. It falls in the seismic zone V, the most active seismic region in the country.

Dr. K S Valdiya, who has done extensive work on Himalayan geology, has written in his recent book "Dynamic Himalayas" that though the strain has been building up for centuries, there has not been a single great earthquake (reading over 8 in the Richter scale), in a segment between the Satluj and Kosi rivers, between which all these places fall. Quoting famous American seismologist R Bilham, he has said that the last great earthquake to occur in this long central sector was the Kathmandu earthquake of 1255 AD.

"Unlocking of the active faults accompanied by sudden release of the stored strain energy will certainly shake the region violently -- and destructively -- once that happens. One does not know when this unlocking will take place, but it will happen certainly someday in the future," Dr. Valdiya said.

The Indian shield was believed to be a moderate seismic zone till the 1993 Latur earthquake. This tremor, with a magnitude of 6.3 on the Richter scale surprised seismologists not only in the country, but abroad as well. "There is no record of an earthquake of such a magnitude occurring in this part of peninsular India," Dr. Harsh K Gupta, leading seismologist and director of the National Geophysical Research Institute (NGRI) had observed then. The Jabalpur earthquake, four years later, too had certain new features.

Dr. J G Negi, a veteran earthquake specialist in the country also has certain interesting things to say about the increasing seismic activity in the country. Earthquakes at places considered safer have prompted scientists to have a re-look at the seismic map of India. For example, the Jabalpur earthquake showed that several river valley rift zones in India are, of late, getting reactivated. This highlights the need to re-draw the existing seismic maps, according to Dr Negi. This tremor falls within the pre- Cambrian Narmada rift zone, which is more than 600 million years old.

Meanwhile, many experts have expressed surprise that India does not have a single full-fledged institute dealing with various aspects of earthquakes including seismic studies and earthquake engineering. "While countries such as the United States and Japan (where earthquakes are as severe a problem as India) have a chain of laboratories, what we have is just some islands of technical expertise scattered around the country," says Prof. R N Iyengar, director of Central Building Research Institute (CBRI), Roorkee. Apart from a seismology division at IMD, the seismological studies are largely confined to a group of scientists in NGRI, under the aegis of the Council of Scientific and Industrial Research (CSIR). Earthquake engineering studies in the country are mainly carried out by a few scientists at CBRI, another CSIR institution, an earthquake engineering department in the Roorkee University and one or two scientists at the Indian Institutes of Technology (IITs), at Delhi, Mumbai and Kanpur.

According to Prof. Iyengar, financial and human resources at the disposal of these experts are paltry and insufficient to cater to the needs of a country of India's size. Similarly, India's earthquake rescue system is so poor that it would do more damage than give any relief to the affected at the time of crisis. The importance attached to the earthquake management in the country can be guaged from the fact that it has been bracketed with other natural calamities like floods and draughts and put under the administrative control of the Union Ministry of Agriculture! On the contrary, the U.S. has a Federal Emergency Management Advisory Board under the direct control of the President and has squads of specially trained troopers for rescue operations in quake- hit areas with fleets of planes and helicopters at their disposal.

"There is no emergency planning in the country", says Prof. Iyengar, who is also a well-known earthquake engineer. First of all, an urgent and concerted effort should be made to re- map all seismic regions. This has become necessary because newer regions are being rattled by tremors. The trend all over the world is micro-zonation, where all areas are divided into smaller regions depending on various parameters including seismic activity, and soil characteristics. Knowing soil conditions is important because it is known today that soil foundations in sand, alluvium, or artificial fills are much more unstable than those in solid rock. If the Government is serious about minimising the damage caused by forthcoming quakes, it has no time to waste and action should be initiated on a war footing, right away.