Micro-zoning of cities, soil test for suitability for construction and applying engineering solutions are desirable to counter any seismic activity affecting the buildings, National Institute of Disaster Management (NIDM) assistant professor Amir Ali Khan has said.
Participating as the course faculty in the five-day training programme on ‘earthquake risk mitigation and management,’ being organised by the Civil Engineering Department of Andhra University in collaboration with NIDM here, Mr. Khan said the Department of Science and Technology and the Union Ministry of Earth Sciences had undertaken the micro-zoning of 30 quake-prone cities in India, including New Delhi, Mumbai and Kolkata, he says.
It is for the city planning wing of the municipal corporations to take up the work based on ‘liquefaction’ studies done by experts and then decide which part of the city is suitable for what kind of construction and initiate the remedial measures, Mr. Khan told The Hindu .
‘Liquefaction’ is a phenomenon when the soil turns into liquid in a fraction of second in the duration of the earthquake. It regains strength later.
However, depending on the existing seismic mapping there are areas where earthquake may not occur at all. But the Latur experience had led to removing the Zone-I, the seismic zone, where quakes do not occur generally.
In 1993, earthquake occurred in Latur in Maharashtra, then in Zone-I with a magnitude that would occur in Zone-IV.
Hence the vulnerability to liquefaction of soils need to be studied and remedial steps be taken accordingly, he suggested, adding that construction need not be given up in any area unless it is warranted.
Citing that the ‘liquefaction’ that simply swallowed dwellings in the recent Indonesian earthquake with earth acting like quicksand, he said unless remedial steps were taken to test soil conditions, the cities would remain vulnerable to quake.
A.P. best prepared
The NIDM studies very severe calamities and carries out research programmes, documentation and training in all aspects of disaster management.
Mr. Khan said the study of the 1999 super cyclone in Odisha had helped in Andhra Pradesh to deal with such severe cyclonic storms better.
“Odisha and Andhra Pradesh are now well prepared to deal with cyclones.
