By: Rakesh Lohumi ( Sr. Editor-ICN Group )
SHIMLA: The numerous hydropower plants, tunnels, bridges and other infrastructures projects have not only enhanced and enlarged the risk profile but also expanded the range and scope of devastation likely to be caused in the eventuality of a major earthquake.
It is indeed a frightening scenario as the entire Himalayan belt is seismically most vulnerable with a high probability of tremors of magnitude 8 and more striking anytime. Collapse of one weak structure, and there are many, could trigger a concrete avalanche and bring down the entire cluster of buildings precariously perched on precipitous hills slopes like pack of cards.
The geologically unstable Himalayan region abounds in poorly constructed buildings, the safety of which is a major concern. Besides, with the penetration of road network into high altitude interior areas new concerns have been raised for the disaster managers. High intensity tremors not only cause damage to buildings, they can also trigger landslides and bring down bridges.
Explaining in detail country’s leading seismologist Arun Bapat says that safety of bridges and roads is very important as a damaged or collapsed bridge or landslide can cut-off affected areas and hamper rescue operations. Bridges are required to undergo periodic maintenance without which they could suffer damage during quakes.
This happened during May 2008 Sichuan earthquake (China) of magnitude 8.0, when out of the total bridges in the city, five collapsed. On examination, it was found that bridge that survived the tremor unharmed, had undergone maintenance just a week before earthquake. The inspection and proper maintenance of bridges, thus, becomes very important from the point of view of disaster management.
Similarly, in hilly terrain landslides and debris of collapsed structures could block roads and bring traffic to a halt. During the 2010 Haiti earthquake the only road leading to the capital town was blocked as houses on hills on either side collapsed. No medical, rescue and relief team vehicle was able to move and this resulted in more damages and deaths.
Bapat asserts that in hilly terrain it is important that roads are not blocked completely and this can be ensured by identifying vulnerable sections and making alternative roads. He has carried out this exercise at Aizwal the capital of Mizoram where there is only a single 10 km running from east to west and with houses on either sides on hills. He identified three such points and suggested construction of shunt routes for emergency. The state government has already implemented the recommendation.
Concerns about earthquake safety are raised every time a major tremor hits the region. The last major seismic event devastated Nepal two years ago. There was a lot of talk in its wake about the preparedness of the country to deal with such geo-hazards and steps required to improve enhance earthquake safety. Mock exercises are being conducted regularly and the focus is on Himachal where a big earthquake is long overdue. All other regions right from Afghanistan to Myanmar have been rocked by major earthquakes in recent years except Himachal, which recorded the last major event in 1905.
However, such exercises have become a routine and, moreover, the focus is on post-disaster management, which mostly boils down to rescue and relief operations. The disaster management plans are largely confined to the post-seismic phase of rescue, rehabilitation and reconstruction. The focus must shift from disaster management (post-seismic event phase ) to long term measures to reduce damage and loss of human lives. Only a comprehensive policy to regulate and restrict construction activity in the seismically active Himalayan ranges and strict enforcement of the seismic code in designing of structures can help contain the fallout of seismic disasters.
