Preparing for seismic hazards

Workshop: More than 30 scientists and engineers, both local and international, met at a two-day workshop to understand seismic hazards and on-going risk reduction initiatives in the country.

Scientists discussed attempts, including empirical research findings and models, to solve questions of a lurking earthquake and concluded that more research is necessary.

Four mega earthquakes occurred during the last 100 years along the Himalayan front of Nepal and India. Records suggest that four earthquakes of magnitude 8+ on the Richter scale occurred before 1950, and 10 more exceeding magnitude 7.5 have occurred in the Himalayan belt in the past 100 years.

Government agencies reported risk reduction and preparation measures for seismic networking, and retrofitting of traditional buildings to improve resistance to seismic activity, among others.

Works and human settlement minister Dorji Choden said that for Bhutan any hazard could take a huge toll on its social and economic wellbeing.

The ministry has developed manuals and guidelines for earthquake resistant structures and trained engineers and artisans.

However, there is a weak compliance and monitoring system on the ground both in rural and urban parts of the country.

“Construction of buildings are generally left up to the owner and the artisans, who are mostly unskilled labourers,” said chief engineer of the engineering services department, Karma Namgyel.

There are only a few qualified structural engineers and there is no certification system for practicing civil engineers.

One of the major constraints in the country is the non-availability of scientific data. “At the same time the scale of potential risks and therefore the losses does not allow the nation to wait for more precise information,” the minister said.

She added that the country could not wait any longer for research.

Therefore, Lyonpo said, it is prudent to use whatever regional data or inferences available for hazard mapping and risk assessments which in turn would entail necessary mitigation measures and implementation.

Following the devastating September 2009 earthquake in Mongar, the government instituted a geophysics division under the geology and mines department in 2011.

The division will read the depth magnitude and location of the earthquakes and fill the scientific information gap. The 14 seismic stations spread across the country will be operational early next year. Installation of intensity meters to study ground shaking is under process.

The data is expected to help structural engineers to develop seismic building codes relevant to local needs.

Disaster management department’s executive engineer, Yeshey Lotey, said one problem is not having a dedicated disaster management officer.

Experts said building capacity at the village level is the most effective preparedness.

Executive Director of National Society for Earthquake Technology, Amod Mani Dixit, said villagers were the most effective in rescuing people in the aftermath of the 2015 Nepal earthquake.

Of the 22,326 people rescued from the rubble, 17,887 were extricated by the communities or on their own.

“This shows the potential of saving lives by building capacity in the communities,” he said.

Experts said that buildings must adhere to national codes. “If we build strong, then there is no need to rebuild,” Dr Amod Mani Dixit said.

Roads in Bhutan are vulnerable, experts said. “There are huge rocks hanging from the road cuttings along the Thimphu-Phuentsholing highway which could cause problems in the event of an earthquake,’ CST lecturer Sarkar said.

He added that stationing road-clearing machineries along the roads is critical for a swift, and effective response.

World Bank sponsored the workshop through the Government of Japan funding.

Tshering Palden

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