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A tectonic catastrophe imminent – says Report

New Delhi, Feb 21 ( G’nY) News service : According to three eminent geophysicistsof India it is believed that therocks below the central Himalayan region, extending from Kangra in Himachal Pradesh to the Bihar-Nepal border and adjoining Gangetic plains are building up stress that could result in a massive seismic release. Theyclaim that an earthquake of magnitude greater than 8on a Richter scale is long overduein the region. The region has seen no large-scale seismic activity for over 700 yearsand if the calamity were to occur,they opine, it would flatten unprotected structures hundreds of kilometres away.

The team consisting of Dr. C.P. Rajendran, professor of geodynamics at the Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, and his colleagues Dr. Kusala Rajendran at the Indian Institute of Science, Bangalore, and Dr. Biju John at the National Institute of Rock Mechanics, Kolar, excavated a trench 30-meter long and four-meter deep across a section of the central Himalayan fault — the collision zone between the Indian and Asian plates to study for anyevidence of a really large earthquake.Based on their study, the team published a paper in the Journal of Geophysical Research on 29th January 2015.

The earth’s crust is broken into distinct regions called tectonic plates. The Himalayas are the result of converging continental tectonic plates. There is an ongoing northward movement of the Indian plate towards Tibet. The paper suggests that the southern part of Tibet that interfaces with India is absorbing about 80 per cent of this convergencewhile the rest has been building up.The central Himalayan region is historically considered a seismic gap in the past centuries and only low magnitude earthquakes have occurred here since 1400 A.D. This, the scientists believe, is not enough to release the strain building up within the plates for last 700 years that islikely to release in the form of great earthquakes (magnitude greater than 8 on a Richter scale) with a huge damage potential.“Though the occurrence of the this catastrophic earthquake is imminent it is very difficult to predict when” states Dr. C.P. Rajendran.

Sections from the scientific community have questioned these beliefs. It seems that the data is not that comprehensive to be used as a foundation of such a major claim. “The topic is quite controversial and the data presented is not concrete enough to reach a conclusion or comment on it”, opines Dr. V.M. Tiwari, Principal Scientist of Geophysics at CSIR-NGRI, Hyderabad. DrTiwari also pointed out that the Himalayan region is a converging belt of continental tectonic plate hence an earthquake is imminent in the region but when it will occur and how big it will be is still not clear.

Pahar

(Photo courtesy: Gn’Y photo bank)

On the same note Dr. Saumitra Mukherjee, Professor of Geology Remote sensing and Space Sciences, Jawaharlal Nehru University, New Delhi, states “As per the recent publication of Dr. C.P. Rajendran and earlier by Dr. Rogers Bilham and Dr. Gaur a big earthquake of 8 Richter scale is waiting in Himalayan foot hill zone specially along the India Nepal Border. Both the papers have used the old statistical data of the seismic events of these two regions and based on recent moderate seismic events the hypothesis has been generated and published.”

In reply to objections raised by Dr. Tiwari and Dr. Mukherjee , Dr. Rajendran reinstated the fact that “We found evidence for two great earthquakes in a section across frontal thrust near Ramnagar. The 2006 work by Dr. Sandeep Kumar, titled ‘Paleoseismic evidence of great surface rupture earthquakes along the Indian Himalaya’, published in the Journal of Geophysical Research, suggests one great earthquake with a wide age range. The difference is that we have come out with more definitive age of the last great earthquake in the 14th centuryas no great earthquake has occurred since then. However, the plate convergence rate with Tibet is calculated to be similar to around 20 mm per year, which means 2 meters of slip per century is accumulating there. Considering 700 years of relapse time 14 meters of slip has accumulated. Therefore we say that the central Himalayan segment is mature enough to generate a great earthquake.”

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