‘Earthquake to cause damage to the dam’

A study conducted by the Roorkee IIT has found that the peak ground acceleration on the Mullaperiyar dam is 0.21 g, Water Resources Minister N.K. Premachandran told reporters.The site-specific study, commissioned by the State government, has found that a quake would cause extensive damage to the dam. [Peak ground acceleration is a measure of how hard the earth shakes in a given geographical area. It can be measured in g (the acceleration due to gravity).] A study conducted by a team headed by R.N. Iyengar in 2001 had put the peak ground acceleration at 0.16 g. Prof. Iyengar's study was based on the findings of the earthquakes that occurred at Koyna and Uttar Kasi.The Tamil Nadu government rejected the findings on the ground that it was not a site-specific study. A study conducted by the Central Water Commission had put the peak ground acceleration at 0.1g. But further studies conducted by experts had put it at 0.12 g.

As per Indian standards, the peak ground acceleration of the Mullaperiyar region is 0.18 g. M.K. Parameswaran Nair who represented the State on the committee tried to drive home the point but it was rejected. Mr. Parameswaran Nair then recorded his dissent, Mr. Premachandran said. It was in this context that the State government entrusted the Roorkee IIT to conduct the site-specific study. The latest study points to the need to construct a new dam adopting international technology to overcome such threats. It has been clearly proved that earthquake measuring three on the Richter Scale may occur near the dam and it would cause extensive damage, he said. The State government has filed three affidavits and other evidence including studies conducted by the Delhi and Roorkee IITs at the Supreme Court. Hearing on the case will begin on July 21.

The Hindu,  Jul 17, 2008