This one was minor, big one is yet to come, say experts

That stress can only be relieved through a ‘‘great quake,’’ said internationally renowned quake specialists Roger Bilham and Peter Molnar of the University of Colorado, Boulder, USA and Vinod K. Gaur, who is with the Indian Institute of Astrophysics, Bangalore.

Speaking to The Sunday Express from Port Blair, where he is studying the Andaman Fault in the wake of the tsunami, Bilham said that today’s quake has ‘‘not been (strong) enough for the pent-up stress to be relieved.’’ The worst case scenario: a quake in what experts call the ‘‘Main Boundary Thrust’’—the line between the two plates—that stretches from Kashmir to the North East, right below the Himalayan range.

Today’s epicentre near Muzaffarabad in PoK is close to four major fault lines in the Indian plate. The fact that the quake was 33 km below the earth’s surface helped reduce the damage. Preliminary reports suggest that it could be in the Tarbela fault that lies in the Indus basin.

Of magnitude 7.4 recorded at 9:20 am IST, the location of the earthquake was 34.6 degree North and 73 degree East. Until late this evening, there were eight tremors, the biggest one at 16:16 which recorded 6 on the Richter scale. A study of the location of these aftershocks shows that it is in the same fault but a bit more north, reflecting the stress that has been built up as a result of the main earthquake in the morning.

The silver lining, Bilham said, was that this should be a ‘‘wake-up call’’ to both India and Pakistan that ‘‘here was a common enemy they share.’’ Extra vigilance and strict monitoring of building codes have to be enforced, he said.

This was echoed by V S Ramamurthy, Secretary, Science and Technology. ‘‘This is a timely cue to get our act together for seismic planning. Nature has been kind enough to give us a powerful reminder but thankfully the Earth has not delivered an immensely devastating blow as was being forecast.’’