CHENNAI: The National Centre for Seismology (NCS) on Tuesday afternoon said an earthquake of magnitude 6.2 struck the Indian Ocean at a depth of 10 km around 12.31 pm and the epicentre was 1,326 km southeast of Colombo in Sri Lanka.
However, the threat of a tsunami was immediately ruled out by scientists at the Indian National Centre for Ocean Information Services (INCOIS), which operates the Indian Tsunami Early Warning Centre (ITEWC).
TM Balakrishnan Nair, Group Director of Ocean Modeling, Applied Research and Services (OMARS) at INCOIS, told The New Indian Express: "For a possibility of a tsunami, the magnitude of the earthquake should be 6.5 or above and the depth less than 10 km. So, in the current scenario, there is no possibility of a tsunami. Moreover, this earthquake has occurred in what is called strike-slip fault, where the blocks more horizontally with portions of tectonic plates grinding laterally past one another and does not typically cause tsunamis. The chances of tsunami are higher near thrust faults, where vertical motion occurs that can displace overlaying water and produce tsunami waves."
Nair said he had received a call from the Tiruchendur temple in Tamil Nadu enquiring about the Indian Ocean earthquake. "I had received a call from the temple, where some festival was underway and about 30,000 people were attending. I communicated that there was no danger." The famous 'Kanda sashti' festival has started in the Tiruchendur temple and thousands of devotees are thronging the coastal town in Thoothukudi district.
On December 26, 2004, an undersea earthquake with a magnitude of 9.1 struck off the coast of the Indonesian island of Sumatra causing one of the largest natural disasters in recorded history. India along with several other countries suffered loss of life and property. After this, the Indian government established the Indian Tsunami Early Warning Centre at INCOIS, Hyderabad under the Ministry of Earth Sciences and has been operational since October 2007.
The early warning system comprises a real-time seismic monitoring and sea-level (tsunami buoys and tide gauges) network. In addition, INCOIS also takes the help of numerical models to assess the tsunami potential at different locations on the coast. The system is operational round the clock on all days. The system is capable of detecting tsunamigenic earthquakes occurring in the Indian Ocean as well as in the global oceans within 10 minutes of the occurrence and disseminates advisories to the concerned authorities. It is providing advisories to all Indian Ocean rim countries as part of the UNESCO-IOC framework.