Mountainous country Nepal on the Himalayas has been devastated recently by a series of earthquakes. It was severely shaken by the shocking earthquake first on April 25 at 11.25 am with 7.9 magnitude for 2 minutes followed by hundreds of aftershocks. During the next two days from the first one two new earthquakes hit Nepal with little lower magnitude 6.9 and 5.1 on April 26 and 27. Another powerful earthquake quivered the nation on May 12 with magnitude of 7.3. The epicentre of the first two earthquakes were located circumscribing Kathmandu, the capital city of Nepal; the first one was at a distance of 80 km to north of Kathmandu and the second was at a distance of 65 km east of Kathmandu. The epicentre of May 12 quake was identified near the Chinese border between the capital of Kathmandu and Mt Everest. The precarious quake wave after its ruinous impact in Nepal could spell its terror in the neighbouring countries like India, Bangladesh, China, Pakistan and Tibet. The effects of these three earthquakes were not only felt in the north- north eastern States of India but also in the south- south eastern territories, which is indicative of its tremendous power.
The present generation of Nepal had not seen and experienced such a natural calamity of this severity. After a long gap of about 80 years it was hit by April 25’s powerful earthquake of 7.9 magnitude. The last Nepal-Bihar earthquake of 8 magnitude in 1934 had engulfed a death toll of 12,000 in Nepal and 7,253 in Bihar along with huge infrastructural damages.
This extreme geo-hazard, which is still occurring at a gap of day or more, has been hitting the Nepal territory nucleating Kathmandu like anything to be thought of. Earthquake, the unprecedented and uncertain hazardous geo-phenomenon, can trigger crustal movement through transverse surface waves of long wavelength and smash the surface structures attached to the ground. How did it hit the Nepal terrain and what misery did it bring for the inhabitants was humanly unthinkable and untold. Buildings, towers, historical monuments were broken like card houses. Cities and towns were turned to heaps of debris within two minutes of quake hit. Residents were buried under the concrete fragments before they thought of what was happening. Thousands were killed, a lot many were missed and the dreadful saga doesn’t turn out to end. Such disaster normally doesn’t allow to count the exact figure of casualty as it goes on adding the number to the list as long as rescue operation continues. But the sorrow is that the damage under debris in large scale needs a long time to be attended for rescue work. Within that span of time, the injured would have been died and bodies would have been decomposed. The Nepal earthquake as on date declares the death toll to be exceeding 8,000 where as the missing figure is as large as 20,000. After a gap of a fortnight it can be easily imagined the size of death toll; moreover the fresh May 12 earthquake added 69 deaths.
If we come down to the effect of quake in India, the size of damage is also not insignificant. A total of 72 people in April 25 and 17 people in May 12 earthquakes died and thousands were injured in India. Bihar being on the top of the list has 72 death cases followed by Uttar Pradesh 13, West Bengal three and Rajasthan one. The effect was remarkably felt in Odisha though damage and death cases were not reported.
Seismological mapping indicates that this region comes under zone-V, a region highly prone to earthquake disaster. Where the Himalayas stands now was a shallow sea namely Tethys sea. According to the plate tectonics concept, the earth crust constitute a number of plates of big and small sizes that float on the mantle melt and move due to the mantle convection current. Similarly two plates, Indian plate and Eurasian plate are moving towards each other at different speed and compressed the sediments of Tethys to erect the newer fold mountain the Himalayas. The movement is still going on and therefore the Himalayas is growing. Indian plate is moving at a rate of 5.5 centimetres per year in north-northeast direction while the Eurasian plate moves at 2 centimetres yearly towards south- southwest direction. Both the plate boundaries collide at the Himalayas and the Indian plate by this way is getting compressed at a rate of 4 millimetre per year. Calculation indicates, after a gap of 80 years from the 1934 quake, the Indian plate has been compressed about 32 centimetres, which could enable it to accumulate enormous energy. Over accumulation of stress could deform the rocks to faulting and released huge amount of energy in form of waves to tremble the crust.
We cannot think of an instant pre-disaster preparedness for earthquake without prediction and warning. One way out to tackle the quake disaster is to adopt a long term cum one time precautionary measure that is to go for earthquake resistant houses. But the past experiences in India have yet to convince ourselves in that light even after we severely suffered in the latur earthquake in 1993 and Bhuj earthquake in 2001. After a number of threats from quake disaster and having been knowing that quake-hit broken buildings takes the lives, we are still with the same mentality to go for high rise apartments and unplanned buildings without earthquake design. In this regard neither any law nor our awareness takes a bit of action. Here is Odisha, the State of natural disasters in the eastern peninsular India. Climatological disasters like cyclones, floods, droughts and heat waves etc are regular and frequent visitors here.
After the 2004 Indian Ocean Tsunami and 2009, 2010 and 2014 earthquake, Odisha adds afresh these two geo-hazards in its long list. last earthquake of 2014 in Odisha with 5.9 magnitude has changed the views of people that there is no such danger out of earthquake here.
The earthquake zonation map of India shows Odisha in zone-II and zone-III. Apart from this there are some lineaments and faults, a few to name Eastern Ghat’s boundary fault and north Odisha boundary fault, which would have been the risk zones. Neotectonism might have developed other new faults and lineaments by this time. They are to be established once again by repeated and continuous surveys. The geographical location of Odisha is such, though it denies the in-terrain origin of earthquake, the highly quake-prone spots in Thailand, Malaysia, Indonesia, Myanmar and even Andaman and Nicobar Island would have affected it through tsunami along the 480 km coastal tract. As such presently most parts of Odisha have been shaken several times by Nepal earthquake. After 1999 Super Cyclone, Odisha for the first time developed a disaster management system, which remained exemplary for other States in the country. After a long journey of learning and experimenting it, we could tackle the 2013 Phailin cyclone with zero casualty. Now the focus must be set at the probable earthquake danger. In this regard, the core principle lies in avoiding the vertical residency and follows the horizontal stretch of urbanisation with quake resistant designs.
(Dr Beura teaches at the PG Dept Of Geology, Utkal University, Bhubaneswar. Email: debanandabeura@rediffmail.com, Ph- 9861213472)