Ummid Assistant

Applications open for Manmohan scholarship at Cambridge

IIM-Trichy to offer short courses too at Chennai centre

Welcome Guest! You are here: Home Special Reports

Tehri dam sitting on an active fault: Indian seismologists

Sunday December 09, 2012 05:44:29 PM, K.S. Jayaraman, IANS

Hyderabad: There is an active fault beneath the Tehri dam that enhances the earthquake risk, scientists of the National Geophysical Research Institute (NGRI) here have reported. The Tehri dam is located near Tehri town in Uttarakhand in the Kumaon-Garhwal Himalayas region.

"The tectonic loading on this active fault due to local seismicity, coupled with the reservoir loading and unloading, may generate earthquake(s) and cause additional seismic risk in this critically stressed region," Sandeep Gupta and co-workers in NGRI claim in their report in the latest issue of "Current Science" published by the Indian Academy of Sciences.

They say their conclusion is based on evidence obtained by mapping of the seismicity pattern in the Kumaon-Garhwal Himalayas region in general and around the Tehri dam in particular, using observations from a temporary seismological network they operated for over 39 months during 2005-2008. During this period, over 20 earthquakes of magnitude 1.6-2.8 on the Richter scale were recorded in a 20-km radius of the dam site.

According to the scientists, the dam site was chosen in 1961, "at the time when the plate tectonics theory was taking birth and researchers were not well-educated with the fundamental mechanism responsible for earthquakes in the Himalayas. Since then, much has changed in the context of our theoretical understanding and observations related to the evolution of the Himalaya and the associated earthquake hazards".

The Tehri dam falls in a region of possible future great earthquakes, the researchers say. The last major earthquake of magnitude 7.7 occurred 209 years ago, in 1803, close to Srinagar-Garhwal. Many intermittent earthquakes including the 1991 Uttarkashi earthquake (magnitude 6.8) have rocked the region and released parts of energy stored elastically due to the movement of the Indian plate.

"Still, a large amount of residual stress has to be released by an earthquake of magnitude possibly not less than 8," the NGRI scientists claim. They say that geodetic levelling observations in the region also suggest the possibility of great earthquakes to release the recoverable elastic strain stored in the upper crust of the outer Himalayas in this part of the Himalayas.

According to the NGRI team, the Tehri dam was initially designed to withstand ground acceleration expected from the maximum credible earthquake of magnitude 7.2, whereas the ground acceleration would be twice this if an earthquake like the 1905 Kangra temblor strikes again.

The scientists have also studied the seismicity around the dam in relation to reservoir filing. They observed an increase in seismicity from December 2005 onwards, after its first filling in October 2005. "We, thus, speculate that seismicity in the vicinity of the Tehri dam may have a linkage with instability created by loading and unloading of the reservoir."

This, coupled with the close proximity of the seismically active fault to the dam, has serious implications for the earthquake hazard scenario and calls for "re-assessment, analysis and further examination of our results using dedicated ground and space-based seismic and geodetic networks," the scientists concluded.



(K.S. Jayaraman can be contacted at killugudi@hotmail.com)


 





 


 

Home | Top of the Page

Comments

Note: By posting your comments here you agree to the terms and conditions of www.ummid.com

Comments powered by DISQUS

i

I

More Headlines

Pakistan's province to celebrate Dilip Kumar's 90th birthday

How Malala got a Mumbai award

Gujarat's 'development' touches select few: PM

England beat India by 7 wickets

President Mursi agrees to delay referendum: Egyptian PM

Modi misleading Gujarat's urban poor on homes: Ajay Maken

Gujarat's second phase poll: 19 percent nominees with criminal records

Omar Abdullah's 'grand alliance' is vindicated in council poll

10 BJP ministers, 50 legislators support me: Yeddyurappa

Parties battle over who their opposition is!

 

Top Stories

With 118 BJP MLAs sharing stage Yeddyurappa launches party

Former Karnataka chief minister B.S. Yeddyurappa Sunday launched his own party and virtually reduced the Jagadish Shettar ministry to a minority 

10 BJP ministers, 50 legislators support me: Yeddyurappa

Parties battle over who their opposition is!

 

  Most Read

Pakistan's province to celebrate Dilip Kumar's 90th birthday

The Khyber Pakhtoonkhwa administration recently planned to acquire the ancestral homes of Dilip Kumar and another Indian legend, Raj Kapoor, and preserve them as national heritage monuments  

How Malala got a Mumbai award

Last month, when Mumbai NGO Harmony Foundation selected Malala for its prestigious "Mother Teresa Memorial Award for Social Justice", it generated considerable excitement over who would receive the honour. The award ceremony took place exactly a week after Pakistani terrorist Ajmal Kasab was hanged Nov 21 for his role in the  

 

  News Pick

With parliament victory, UPA on firmer wicket

The consolation which the Bharatiya Janata Party (BJP) is trying to derive from the fact that the Congress is in a minority in the Lok Sabha on the issue of FDI

Omar Abdullah's 'grand alliance' is vindicated in council poll

The clean sweep by the ruling National Conference (NC)-Congress alliance, which won the polls for all the four legislative council seats  

Drugs, chillums, phones, condoms in a Goa prison!

Drugs, chillums, mobile phones, fancy razors, exotic condoms... No it's not the flea market we are talking about. Welcome to the standard fare in Goa's oldest and most secure - the Aguada Central Jail.  

Unification of India, Pakistan must to solve Kashmir issue: Katju

Addressing a seminar on "Reporting conflict zones", organized by the India Chapter of South Asia Media Commission, Katju said: "Now the time has come for India and  

Clairvoyance or Hope? Youth predicts end to Kashmir sufferings

Anguish of Kashmiri People: Are we listening?

 

Picture of the Day

Tri Service Chiefs paying homage at Amar Jawan Jyoti, India Gate on the occasion of Navy Day in New Delhi on December 04, 2012.

 

Recommend the story to your friends

 

 
 
 
 
 
 
 
 

RSS  |  Contact us

 

| Quick links

News

 

Subscribe to

Ummid Assistant

 

National

Science & Technology

RSS

Scholarships

About us

International

Health

Twitter

Government Schemes

Feedback

Regional

History

Facebook

Education

Register

Politics

Opinion

Newsletter

Contact us

Business

The Funny Side

Education & Career

     

 

 

Ummid.com: Disclaimer | Terms of Use | Advertise with us | Link Exchange

Ummid.com is part of the Awaz Multimedia & Publications providing World News, News Analysis and Feature Articles on Education, Health. Politics, Technology, Sports, Entertainment, Industry etc. The articles or the views displayed on this website are for public information and in no way describe the editorial views. The users are entitled to use this site subject to the terms and conditions mentioned.

2012 Awaz Multimedia & Publications. All rights reserved.