Owing to haphazard construction, next quake can reduce Shimla into rubble : Report NDMA

Even as the death toll from the 7.9 magnitude earthquake climbs to over 3,200 and stunned survivors struggle to come to terms with the magnitude of the disaster, experts say the worst is yet to come. The quake, which reduced large parts of Kathmandu to rubble, is not the ‘great Himalayan quake’ that the region has been bracing for.

SHIMLA: In last few years, Himachal Pradesh (HP) is witnessing increased frequency of earthquakes up to 5 magnitude on the Richter scale, which has led to the fear of bigger quakes hitting the state in future. While experts are claiming low intensity quakes release seismic energy to avoid bigger earthquakes, unplanned constructions, even on steep hills, has led to fear of widespread destruction if a high magnitude earthquake hits the state.

A bigger quake haunts Himalayas

The devastating earthquake that originated in Nepal on Saturday may have been the strongest to hit the central Himalayan region in the last 80 years, but scientists say this was not the big one that they had been fearing would strike the area.

Prof Sankar Kumar Nath of IIT Kharagpur, who has studied seismic activity in the Himalayan region,said

He further said,

If you look at it differently, we are actually lucky that only a 7.9-magnitude earthquake has come. I would be very happy to have a few 7.9-magnitude earthquakes than a 9-magnitude earthquake which would be absolute disaster. The trouble is that in terms of energy release, which is what causes the damage, it would take 40 to 50 earthquakes of magnitude 7.9 to avoid an earthquake of magnitude 9.

A magnitude 9 earthquake is ten times bigger but approximately 32 times stronger than a magnitude 8 earthquake — magnitude is a merely a reflection of the height of seismic waves measured on a seismograph.
While India has escaped relatively unhurt in Saturday’s earthquake, the danger of aftershocks still persists.

The areas falling in districts Chamba, Kangra, Mandi, Kullu, Hamirpur and Bilaspur are very sensitive as they fall in the very high damage risk seismic zone (Zone V), whereas the rest of the areas falls in high damage risk zone (Zone IV).

A study had shown that if an earthquake of bigger magnitude takes place in Himachal during night hours, then it would kill 2.40 lakh people while during the morning hour casualty would be around 1.6 lakh.

An assistant professor of geology at HPU’s regional centre at Dharamshala, Mukta, said that after a major earthquake in 2005, whose epicenter was in Kashmir, Himachal has been witnessing low intensity earthquakes at regular intervals.

She further added,

Last year in October-November around 7-8 low intensity earthquakes were recorded in Dharamshala and Baijnath areas of Kangra district in a span of 3-4 days.

She said Kangra is a seismically-prone area. She said in the seismic-prone areas construction needs to be regulated and earthquake resistant buildings need to be built to minimize the impact of quakes.

She added,

If the buildings are not made according to the set norms then even a 4-5 magnitude tremor can destroy those.

Massive haphazard constructions in the hill towns of Shimla, Dharamshala, Dalhousie and Kullu have made them prone to natural hazards like earthquake. In Shimla, construction has taken place on steep slopes. An earthquake of 8 or above magnitude can turn the tourist town into rubbles as 14 major localities are situated on an average slope of 35 to 70 degrees with peak population density of 2,000 to 3,000 per hectare, despite the fact that the city falls under seismic zone IV.

A study conducted by the National Disaster Management Authority (NDMA) has shown that during natural disasters like earthquake 17% people would be injured while 3-4% would die.

Development plan of Shimla prepared by the town and country planning department has identified geologically week areas including northern slopes of the Ridge extending up to Grand Hotel in the west covering Lakkar Bazar, including the Central School extending to Auckland Nursery School, then down to Dhobi Ghat below Idgah electric sub-station. The slide-prone areas include Laddakhi Muhalla (Krishna Nagar) and the spur below directorate of education department and surrounding areas of Hotel Clark’s.

Localities like Cemetery, Sanjauli, Jiunu Colony, Chakkar, Katchi Ghati and Lower Bharari are susceptible to major mishaps during earthquakes whereby chain effect of collapse of building may affect many buildings on slopes down below.

According to the report prepared by Himachal Pradesh State Disaster Management Authority, seismically the state lies in the great Alpine-Himalayan seismic belt running from Alps mountains through Serbia, Croatia, Turkey, Iran, Afghanistan, Pakistan, India, Nepal, Bhutan and Burma.

Most severe earthquakes in Himachal

April 4, 1905 in Kangra: An earthquake of 7.8 magnitude killed 20,000 people and 53,000 domestic animals had perished while one lakh houses were destroyed. Economic cost of recovery was estimated at Rs 29 lakh during that time.

January 19, 1975 in Kinnaur: A quake of 6.8 magnitude had killed 60 people while 100 others were badly injured. About 2,000 dwellings were devastated and 2,500 people rendered homeless.

April 26, 1986 in Dharamshala: A tremor of 5.5 magnitude had killed six people and caused extensive damage to buildings. Loss was estimated at Rs 65 crore.

March 24, 1995 in Chamba: An earthquake of 4.9 magnitude had left over 70% houses with cracks.

July 29, 1997 in Sundernagar: A quake of 5.0 magnitude had left around 1,000 houses damaged.

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