Microzonation to make city tremor-readyhttps://indianexpress.com/article/cities/delhi/microzonation-to-make-city-tremorready/

Microzonation to make city tremor-ready

Procedure will assess soil structure across Delhi to give risk assessments on a zone-wise basis.

As Delhi gets working on a full-fledged plan to minimise impact in the eventuality of a high-intensity earthquake in or around the city,the Delhi Disaster Management Authority (DDMA) is likely to take up a microzonation exercise of Delhi. The National Disaster Management Authority (NDMA) has ordered microzonation of 30 other cities falling in Zone IV of the Seismic Zone Mapping.

Microzonation,a zone-wise risk assessment,is carried out to identify the different hazard potential in case of an earthquake in individual areas. In Delhi,the process would assess soil structure in various parts of the Capital to give risk assessments on a zone-wise basis. Once completed,this will help the NDMA in formulating area-centric safety guidelines.

DDMA secretary Vijay Dev said microzonation would take some time to implement. “The proposal for microzonation,together with other thrust areas that need to be moved forward,would be taken up soon,” he said.

The NDMA had decided upon a zone-wise risk assessment of the impact on 30 cities that fall under the severe intensity seismic zone. In Delhi,the DDMA would ready the proposal,which would be carried out by the India Meteorological Department (IMD).


“Character of soil structure in Delhi is not uniform and the impact of an earthquake would vary. To evaluate this,micro-zonation process at a map scale of 1:50,000 has already been done. A fresh process for further detailed microzonation in the 1:10,000 scale is on,” R S Dattatrayam,a scientist with IMD’s Seismic Department,told agencies.

This seismic microzonation would help seismologists categorise the soil type and structure of a particular region and assess the damage,which might be caused to life or property in case of an earthquake. Based on this micro-zonation data,the NDMA would come out with specific area-centric safety guidelines.

Dev said close to 240 engineers of Municipal Corporation of Delhi will also be trained to detect vulnerable structures in high-risk areas in Delhi. “At present,the engineers are not adequately trained to assess structural safety.”

This year,till February 16,there were 15 earthquakes in India,the latest being one with a magnitude of 5.0 on the Richter scale off the West Coast of Great Nicobar Islands. According to IMD,there were 80 earthquakes in India in 2011,measuring between 3.5 and 6.9 on the Richter scale. Most these quakes occurred in J&K,Haryana and Punjab.

(With inputs from PTI)