The government, which is battling protests over Koodankulam nuclear power plant in Tamil Nadu, is in for another shock with two leading geologists warning that Jaitapur in Maharashtra is not immune from large earthquakes.

“The apparent seismic quietness of Jaitapur does not mean that a severe earthquake can not occur there”, said Dr Vinod K Guar, eminent geologist at the CSIR Centre for Mathematical Modelling and Computer Simulation, Bangalore and his long-time scientific collaborator Roger Bilham of the University of Colorado.

The scientists said that it would be wrong to exclude the possibility of a large quake in Jaitapur because available seismic data is insufficient. Jaitapur , they said, lies in the same ‘compressional stress regime’ that has generated two large quake in the region in the past fifty years at Latur (magnitude 6.3) and Koyna (magnitude 6.4), both of which are located at approximately same latitude as Jaitapur.

“A similar sized earthquake could possibly occur directly beneath the power plant. The probability of this earthquake occurring is low but it is nevertheless possible”, the scientists said in their paper in scientific journal Current Science, published by the Indian Academy of Sciences, Bangalore.

Since Koyna and Latur have been relieved of local tectonic stresses, ‘no shallow fault between latitude 16 degree and 19 degree (in which lies Jaitapur) may be invulnerable to future magnitude 6 and above rupture’, the scientists said. The occurrence of 1967 quake in Koyna has presumably loaded the Jaitapur region as a result of stress transfer. Though the probability of a large quake at Jaitapur is low, it is relevant from the point of view of designing nuclear power plants.
The scientists examined all available seismic records including those from the US Geological Service and the Indian Meteorological Department (IMD) to come to the conclusion.

The Nuclear Power Corporation of India Limited (NPCIL), which plans to build the power plant at Jaitapur with reactors from France, maintains that the site falls in the seismic zone III, where earthquake risk is low. However, Gaur and Bilham have rejected currently used hazard and seismic risk maps because ‘they assume that the seismic energy release of recent years is representative of future’. Latur was considered as a region of low seismic risk till the 1993 quake.

The scientific paper has provided new ammunition to anti-nuclear forces. The paper, Greenpeace said in a statement, showed that there is no scientific consensus on the issue of seismicity in the Jaitapur region. “The government can not say that seismicity is a sorted issue”, the statement said.

 

Source: India Today