The Hindu , 01 August 2006

NGRI research on `tsunami precursors'

ELURU: N. Purnachandra Rao, a scientist of the National Geophysical Research Institute (NGRI), on Monday said the NGRI had initiated a study on `tsunami precursors'. Mr Rao was speaking at a two-day seminar on "Cyclone, earthquake, tsunami and disaster management" at St. Theressa's College for Women. He revealed that the NGRI had deputed its scientists to Andhra Pradesh and Tamil Nadu coast for the study, which intended to evolve a tsunami warning system by basing on the so-called precursors.

The seismic waves that tend to travel at the rate of 6 km per second, much faster than the tsunami waves, could be considered one of such precursors. The NGRI was contemplating the use of seismograms for sensing the seismic waves, a virtual harbinger of tsunami. He said the NGRI had also set up Global Positioning System (GPS) stations in the Andaman to track the changes, if any, in movement of the earth after the tsunami in December, 2004.

An enigma

The two quakes that struck the Andaman-Sumatra arc on December 26, 2004, and March 8, 2005 on the India-Burma and Australia-Sunda plate boundaries in a short span of three months proved to be an enigma for scientists, necessitating an in-depth study on causative factors, he said. "This is for the first time in the history of seismology that two great earthquakes have occurred in close spatial proximity in such a quick succession," he said.