Delhi’s seismic network
is being further strengthened with the Department of Science and
Technology (DST) having sponsored a new project entitled ‘Augmented
- Delhi Strong Motion Accelerograph’ (A-DSMA). Recognising the
pioneering work done by the Central Building Research Institute
(CBRI), Roorkee, the DST has handed over the 7.5 million rupee
project to CBRI.
Under this project,
the CBRI will procure and install 12 additional digital strong
motion accelerographs in areas not adequately covered. Delhi has
fast changing sub-surface features making it behave quite differently
in adjoining localities in case of major earthquakes. For this,
thorough investigation and data collection are essential to assess
the damage potential of different parts in a realistic manner.
Once the Augmented DSMA network becomes operational, all types
of sub-surface categories of the city will be covered.
The CBRI is operating
the DSMA network in and around Delhi since 1996 under the DST-supported
project ‘Strong Motion Seismic Instrumentation’. The network comprises
16 units of digital triaxial strong motion accelerographs. Of
these 8 are located inside Delhi and the rest around the city
within a radius of 200 kms.
The city is spreadover
an area of approximately 30 X 30 kms with highly sensitive and
strategic locations, structures and dense human population. The
region surrounding the city is known to be seismically active
through the ages. Small to medium earthquakes are frequently recorded.
Microzonation study of Delhi has thus been given national priority,
taking into consideration the vulnerability of the region.
