By Killigudi Jayaraman, IANS
Bangalore : India’s tsunami watchdog has denied suggestions that its tsunami alert Wednesday evening was based on earthquake data released by the US geological survey and not on India’s own warning system.
“Our interim warning system is in place and working,” Shailesh Naik, director of the Indian National Centre for Ocean Information System (INCOIS), told IANS.
“The tsunami ‘alert’ for the Andaman and Nicobar Islands and ‘watch’ for the mainland was issued by analysing data from our own instruments,” he stressed.
Naik said the observational platform consisting of seismometers and tide gauges are all already in place. “We are currently reviewing the various processes for quickly integrating data from different instruments to make credible predictions,” he said.
Once this is over, the warning system will be declared operational. This, he said, would happen by the end of the month.
Naik said Wednesday’s 8.1 magnitude quake off Indonesia’s Sumatra island, which prompted a “red” alert from INCOIS and another quake of the same magnitude in the same area Thursday morning, provided the “test runs” for the Indian tsunami warning system.
He said after the morning quake, his centre issued an “orange” alert for the Andamans, meaning a tsunami was “likely” but not certain.
Some scientists at the National Geophysical Research Institute in Hyderabad, however, wondered why INCOIS took more than five hours after Wednesday’s quake (which took place at 4.30 p.m) to withdraw the alert.
“If INCOIS had used data from its instruments, it could have withdrawn its warning by 7.00 p.m. itself because any of its instruments would or wouldn’t have recorded the wave in the Great Nicobar or in Bay of Bengal by that time,” a scientists said on condition of anonymity.
“It only shows that tsunami warning system of India is not in place and is not ticking.”
Naik said his centre did not issue any “warning” for the mainland and so there was no question of withdrawing it. He said for the mainland INCOIS advised a “watch”, meaning that the official machinery should be in readiness just in case, but people need not be warned.
He said Wednesday’s event did produce tsunami but it was not destructive. The tsunami wave height was six cm in the Sri Lankan coast and one-two cm along India’s coast.
The US geological survey publishes detailed earthquake data almost immediately after the event in its website accessible to anyone. INCOIS receives earthquake information from India Meteorological Department and also the Japan Meteorological Agency.
INCOIS platform includes four bottom pressure recorders. One near the Andaman and Nicobar Islands can sense a tsunami, which is further confirmed by tide gauges, numbering 15, located at coasts.