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Experts call for fresh seismic zoning of the country

Drawn up years ago, the seismic zoning of the country needs ''major modifications'' in view of a string of earthquakes battering most stable regions with an alarming frequency and disastrous consequences, experts said.

''Recent seismic activities in peninsular India and other parts of south India, including quakes in Idukki and Bangalore last week, have made it imperative to re-examine our seismic zoning,'' Dr S K Srivastava, additional director general, seismology, with the Indian Meteorological Department in New Delhi, told UNI.`

"With seismic activities becoming hyperactive in recent times in large parts of the country, a few stable regions in zone one and two need modifications," Dr Srivastava said.

Bangalore is in zone two, yet it experienced an earthquake of the magnitude of 4.3 on the Richter Scale. Idukki in Kerala, also considered to be a stable region in terms of seismic activity, experienced major tremors earlier this week. ''All these are indicative of an urgent need for a fresh exercise for seismic zonation of the country.''

M M Gupta, former deputy director general of meteorology, voicing similar concerns, said there had been major earthquakes in recent times and scientific studies had to be carried out for a better mapping of the country for measuring seismic activity in all regions.

''Latur is in zone one which indicates least seismicity, yet an earthquake of the magnitude of 6.4 on the Richter Scale struck in 1994 with unprecedented consequences in terms of loss of lives and property,'' he said.

Srivastava said the country had been divided into five seismic zones. While zone one indicates least seismic activity, zone five means that the region can experience an earthquake of the magnitude of eight plus on the Richter Scale.

''Delhi is in zone four which means that it can experience a tremblor up to seven plus on the Richter Scale. But all these data have to be reviewed because earthquakes in recent times have been wreaking unpredictable damages in stable regions of the country.''

He said a refashioning of seismic zones had now become possible because of a lot of seismic data has been collected in recent years with state-of-the-art equipment. ''If we collate our old and new data, perhaps some modifications may appear in seismic zonation.

"In addition, we need to do micro-zonations of major metros like Delhi, Bombay and Calcutta in order to give better feedback in town planning and building practices,'' he said.

Srivastava said the entire country, in fact, needed quake- resistance evaluations for an early forewarning of the natural disaster and also cushioning its impact.

A proposal in this regard has already been approved by the government and the implementation of this programme is in progress.

Under the plan, the earthquake-risk evaluation will be done in a phased manner in the entire country. ''This is the least which is required to be done and we are already doing it,'' he disclosed.

The seismic department of the IMD has started collecting data round-the-clock and its inputs will be used for micro-zonation of the country.

''However, there is no proven scientific technique anywhere in the world by which earthquakes can be predicted with any remarkable degree of accuracy in terms of space and time,'' the seismic expert asserted.

On Tuesday, Union Home Minister L K Advani told reporters that the government would consider financing research for construction of earthquake-resistant structures on the lines of Japan in view of the country's increasing vulnerability to killer tremors during the past ten years.

''We used to think that we are less vulnerable to earthquakes. But after the experience of Uttarkashi, Latur, Jabalpur and Gujarat there is a need to reassess our position in so far as vulnerability to earthquakes is concerned and take suitable measures,'' Advani said.

UNI

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