New Delhi: Pondicherry is sitting on a "tectonic triple junction" making it seismically vulnerable, according to a new finding at the National Geophysical Research Institute (NGRI) in Hyderabad.

Based on this finding and considering that Pondicherry had experienced a 5.6 magnitude earthquake a year ago, NGRI researcher U Raval has cautioned that "the region needs better seismic monitoring" than at present.

According to Raval who has specialised in the theory of plate tectonics, "available geophysical, seismic, tectonic, and geodynamic evidence suggest that a tectonic junction more prominent than hitherto realised may exist near Pondicherry".

"There are three major gravity axes which appear to emanate from the region near Pondicherry," Raval reported in the Journal of the Geological Society of India. junction of two "magnetic trends" also lies offshore near Pondicherry, he said.

The gravity high axes- lines exhibiting large anomalies in earth's gravitational field- "appear to be indicative of some sort of branching of thermo-magnetic processes near this junction," he said.

Under the theory of plate tectonics earth's crust is made of several plates set in motion after a single landmass called Gondwanaland broke up some 200 million years ago. Indian plate that split from Antarctica had been moving northward on a collision course with Asian plate.

PTI