Science

No Lessons Learnt From Quakes in India’s Northeast

Due to the government’s negligence, many publicly funded buildings suffered severe damage during a recent quake in Imphal – which is both ironic and a betrayal of public trust.

People gather near a collapsed building after a massive earthquake in Imphal on January 4, 2016. Credit: PTI

People gather near a collapsed building after a massive earthquake in Imphal on January 4, 2016. Credit: PTI

New Delhi: It is often said that earthquakes don’t kill people, the buildings do. If building codes have not been enforced in seismically active zones, even moderate intensity quakes can cause widespread damage to structures and injure people. This is what has been happening in India’s northeast region, according to a new study.

Manipur was struck by an earthquake of magnitude 6.7 on January 4, 2016, that devastated the state capital Imphal and adjoining areas. The event also gave scientists a chance to understand the risks posed to buildings and construction practices in the region. While many buildings collapsed, it had been noted that the damage caused to public buildings was disproportionate to the quake’s observed intensity.

Scientists from three IITs – Kanpur, Guwahati and Patna – undertook a reconnaissance survey of quake-affected regions right after the Imphal quake, and visited the area after three months to study the condition of damaged structures and supervise restoration work. The results of this study were published in the journal Current Science.

They found that while several reinforced concrete (RC) buildings in Imphal had suffered varying degrees of damage, traditional wooden houses made with bamboo and wood (known as ‘shing-khim’) reported none. Government buildings were damaged heavily because they had not conformed to the seismic code, exacerbated by the poor quality of raw materials and shoddy workmanship.

“The seismic risk in the region is growing at an alarming pace with an increasing inventory of vulnerable construction,” the study concluded. The 2016 quake, it said, “should be regarded as a preview of what is likely to happen in the event of greater shaking expected for the region and should hasten the community to take necessary steps.”

Durgesh C. Rai, a professor of civil engineering at IIT Kanpur and a member of the study, told India Science Wire that “despite considerable awareness in public about earthquakes and associated risks, both public and administrators chose to ignore the threat and continued to build structures [that] were not earthquake-resistant.” Due to such negligence, he said, “many publicly funded buildings suffered severe damage under shaking intensity of VI–VII, which is not only ironic but also represents the utter betrayal of public trust.”

Buildings at the inter-state bus terminal, the Government Polytechnic and Central Agriculture University (CAU) are all structures whose construction has been under government supervision and with public money. They were expected to ‘perform’ satisfactorily during earthquakes – but they all experienced moderate to severe damage. Large campuses like the CAU have been built atop landfill soil and so they performed very poorly during the quake, the study said.

New concrete buildings of the famous Ima Keithel also suffered damage. This market had earlier made do with bamboo structures; they were functional but in bad condition. So the government dismantled the market and built three concrete structures in 2010. All three buildings had a similar elevation and plan but only one of them experienced the quake the way it was designed to.

“Traditional constructions using lighter timber and bamboo have performed well and no damage to such structures in Imphal was reported,” Rai added. “Despite available knowledge, seismic safety remains neglected and society is not adequately prepared due to lack of implementation.” He said the lessons from the Manipur quake are applicable to the entire northeast region.

Dinesh C. Sharma is a science writer with India Science Wire. He tweets at @dineshcsharma.

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