Centre launches 'Seismic Microzonation' to mitigate earthquake risks

Guwahati, Jan 10: Earthquakes do not kill, but weak structures do. Keeping this in mind, the Government of India has started the process of seismic microzonation of vulnerable cities and towns as a flagship programme so that adequate precautions can be taken to minimise loss of human lives in case of a major earthquake, the Director of the National Centre of Seismology, Dr. OP Mishra, said.

In an interview with The Assam Tribune, Dr. Mishra, who is a noted seismologist, said that strengthening the buildings is the key to reducing mortality during earthquakes, and that is why the Government of India has taken up this issue seriously. The National Centre of Seismology is carrying out the process of seismic microzonation of vulnerable cities and towns all over the country.

On the basis of it, new building design codes will come up, and it will be up to the concerned authorities to ensure that the building codes are strictly implemented.

Dr. Mishra pointed out that the Northeast region is highly vulnerable to major earthquakes as it falls under zone V seismicity and has a history of facing major earthquakes. He said that the seismic microzonation of Guwahati has been completed, while the study of Gangtok is on. In a phased manner, all the cities and towns of the Northeast will be covered under the programme.

He said that after the study is completed and new building design codes come up, the concerned authorities would have to carry out a survey of the old buildings and carry out retrofitting wherever required. While granting permission for new buildings, the authorities will have to ensure that the building design codes are strictly adhered to.

Dr. Mishra revealed that Japan is way ahead of India in carrying out detailed studies and designing buildings to withstand earthquakes. "We are still lagging behind. Japan carried out seismic microzonation and constructed buildings to mitigate the loss of human lives in the 1980s and 1990s. We are far behind, but on the positive side, the Government of India has now taken up the issue seriously," he added.

Replying to a question on the vulnerability of the Northeast, Dr. Mishra admitted that the entire region is highly vulnerable. He pointed out that the casualties in earthquakes not only depend on the magnitude of the quake but also on several other factors, including the timing of the quake. He said that if an earthquake strikes at night, the casualties are often more because people are sleeping at that time and they do not have the time to take precautions.

When asked whether the mega dam proposed to be built by China would be disastrous for India as it will be constructed in a highly seismic zone, Dr. Mishra said, "It is difficult for me to comment on the issue as I have not seen the design of the dam. But I am sure the Chinese government must have taken precautions before investing so much money." However, he said that the design of the Doyang dam is world-class and the seismic studies were carried out while preparing the design.

On the possibility of a mega quake striking the region, Dr. Mishra admitted that it would be difficult to predict. But at the same time, he said that lots of seismic activities are taking place along the Indo-Myanmar area, and that must be releasing energy. If energy is not released from time to time, accumulation of energy usually is released in the form of a mega earthquake, he pointed out.

By

R Dutta Choudhury