SciDev.Net

[NEW DELHI] India urgently needs to make buildings and dams better able to survive major earthquakes and to update building codes, warn scientists.

Researchers from the Indian Institute of technology (IIT) conducted a hazard assessment for the Indian peninsula by analysing previous seismic activity. They found that the threat is underestimated in current design standards.

The Indian peninsula is located in a stable region away from continental plate boundaries where earthquakes are common. But a significant number of earthquakes — including some large and damaging ones — do still occur.

The scientists say the threat of earthquakes in some major urban areas, such as Mumbai, was "significantly" underestimated by the Bureau of Indian Standards in 2002, and should be taken into account in structural designs.

"The results imply that the level of seismic safety of structures designed based on current standards is lower than its desired level," says Ravi Sinha, professor of civil engineering at IIT.

The scientists noted an apparent increase in seismic activity due to better seismological instrumentation to record earthquakes, which requires a closer consideration of construction standards.

They say their work is "useful in specifying design levels for upgrading and [reinforcing] major structures such as dams and industrial facilities to the desired level of seismic safety."

A devastating earthquake in Latur, central India, in September 1993 killed about 10,000 people and destroyed over 30,000 houses. It forced Indian geologists to revise their earlier theories and propose that the entire Indian sub-continent is at risk of quakes.

The research is published in the February issue of the Bulletin of the Seismological Society of America.

Reference: Bulletin of the Seismological Society of America, doi: 10.1785/0120050127 (2007)