Wednesday, January 18, 2012

Conversations About Seismic Risk Of The Proposed Jaitapur Nuclear Plant

I get mails from reporters asking me geology questions. I got one today morning from a reporter of a big newspaper about the controversy regarding the siting of a proposed nuclear power plant near the village of Jaitapur in southern Maharashtra.

With his permission I have pasted his question and my reply below-

Dear Suvrat,

After the press conference by Dr Bilham regarding the earthquake hazard  to Jaitapur. NPCIL has issued a press release, which mentions about the various studies carried out on behalf of NPCIL. They are mentioned in the file attached with this mail. I was wondering whether they have taken adequate test for the Jaitapur site.

I would be obliged if you could see the mail and give your feedback.

Warm Regards

Dr. Bilham is Dr. Roger Bilham who along with Dr. Vinod Gaur recently published a paper (open access) on the tectonic situation and seismic risk along the southern Maharashtra region. My post summarizing the paper is here.  NPCIL is the Nuclear Power Corporation of India Limited and their press release can be found here.

Here is my reply. I've added a couple of words (in black for clarity) -

Hi XX-

The list itself covers all the geological studies that can be done. I cannot off course speak to whether individual studies were comprehensive or not. I am curious whether the NPCIL already has or is planning on making all these studies available to the public so that independent experts may evaluate the findings of the government scientists.

Geologically there are two limitations here. One is that, there is no reliable historical documentation of large seismic events from this area (Jaitapur). Second, there is no surface expression of faults and displacements along these faults that may give us some idea whether and with what frequency was this area affected by large earthquakes in pre-historic times. Therefore it is difficult to develop a robust statistical extrapolation of the risk of large earthquakes.

This uncertainty means that people can read what they want to into all the tests and theories about this area. People who don't want a nuclear plant can say.. look, an earthquake can hit any time.. just like Latur. No scientist can disagree with that.

On the other hand the nuclear establishment can say with some justification that over the life cycle of a nuclear plant (next 100 or so years) there is a small probability of a moderate size earthquake (6 -7 Richter) and an even minuter chance of a tsunami and we can deal with the engineering requirements.

I don't see any side giving way because the opposition to nuclear energy goes deeper than just geological considerations and its hard to change the government's mind on anything.   From what I have read about the general geology of the area I suspect that everyone can beat the geological risk angle to death and get nothing new out of it.

One impression I did make when I followed some of the panel discussions on the Tamil Nadu nuclear plant on TV shows is that some of the nuclear scientists were dismissive and even contemptuous of civic society concerns. Maybe a similar attitude has aggravated the situation at Jaitapur.


Latur is the area in southern Maharashtra which suffered a 6.4 mag earthquake in 1993. It was long thought to be at low seismic risk. The Indian government is promising to engage with civic society on all aspects of the construction of the many planned nuclear power plants and in that spirit of openness I hope they make the relevant geological studies available for anyone to critique.

I will post more on this topic as the story develops.

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