State less prone to earthquakes, say experts

Tremors: Residents and fishermen in coastal areas put on tsunami alert

Bangalore and most parts of Karnataka are located in the least (seismic) active zone in the country, according to the seismic map of Indian Meteorological Department.

The country is divided into five different zones, depending on the seismic activities. While zone one has the least activity, zone five has the highest. Parts of Malnad and Coastal regions of the State fall in zone two and three.

According to the Karnataka State Natural Disaster Monitoring Centre (KSNDMC), there was no earthquake in Bangalore or anywhere in the State.

“What people felt was only the impact of the massive earthquake that occurred in Sumatra, Indonesia,” KSNDMC Director V S Prakash said.

He said the State never had a history of earthquakes since it is not located on tectonic plates responsible for tremors.

As a precautionary measure, the KSNDMC has sent a tsunami alert for the coastal areas of the State, particularly Mangalore and Udupi, with an apprehension that tidal waves, if at all they originate, might strike the State’s coast Wednesday between 7 pm and 9 pm.

Kusala Rajendran, professor at the Centre for Earth Science studies, IISc, Bangalore, said there was no local seismic activity reported in the entire sub-continent.

There will be mild vibrations due to the powerful waves of the earthquake in Indonesia. With earthquake of this magnitude, vibrations will be felt globally, she explained.

Wednesday’s earthquake of 8.6 magnitude was less severe than the 9.3 magnitude in December 2004, which brought tsunami to the east coast of India killing hundreds of people.

She said such vibrations will be felt strongly in high-rise buildings. Most of those who were on the ground did not feel it. The intensity of vibration was more in places like Chennai and Kochi, while it was mild in other places, including Bangalore.

Prof Rajendran said: “Bangalore is sitting on a hard surface made of old igneous rocks. Here seismic activities are not likely. Earthquake usually occurs in places where the earth is covered by sedimentary rocks or weak areas.

Flood of calls

The Meteorological Department in the City was flooded with panic calls soon after the tremors.
Sources in the department said most of the calls were from the residents of highrises in Electronics City, Koramangala and Bangalore South region.

The sources said the intensity of tremors was very less but the impact magnifies in the skyscrapers.