On this day in 2004, when Tsunami struck the Indian coastline due to the great Sumatra earthquake, not many people in India were aware of its devastating capacity to cause loss of life and damage to property. The Ministry of Earth Sciences established the Indian Tsunami Early Warning Centre (ITEWS) at the Indian National Centre for Ocean Information Systems (INCOIS) here in October 2007.
The centre has issued timely warnings for seven Tsunami events in less than 10 minutes for 101 earthquakes in the Indian ocean since then to about 25 countries. The warnings have been issued in the form of email, SMS, fax and global communication systems, said INCOIS director T. Srinivasa Kumar on Friday.
Warnings are issued after any major earthquake in the Indian Ocean and the centre over the years has monitored 630 earthquakes of magnitude ≥ 6.5. “Tsunami early warning is a race against time and through continuous effort of scientists, there has been substantial improvement in Tsunami warnings and timelines by deploying better sensors, accurate models and multiple modes of dissemination,” he said.
It came into being following the great Sumatra earthquake (Mw 9.3) of December 26, 2004 and the devastation caused which exposed the vulnerability of the Indian coastline and unprecedented loss of life and damage to property in Indian Ocean rim countries.
ITWES functions round the clock, has a real-time seismic monitoring network to detect Tsunamigenic earthquakes, real-time sea-level network of Tsunami buoys and tide gauges to monitor the Tsunami waves, and numerical models to estimate the Tsunami travel times and wave heights at the coast, explained Dr. Kumar.
While innovative concepts in Tsunami modeling, mapping of coastal inundation, decision support system and standard operating procedures were introduced, update of hazard assessments, warning capabilities and community preparedness is imperative because of the complexity of events.
This was amplified during the Palu Tsunami ( Sept 28, 2018) triggered by submarine landslide, Sunda Strait Tsunami (Dec 22 , 2018) following the Anak-Krakatau volcano eruption, and most recent tsunami in Turkey and Greece (Oct 30, 2020) to issue the warnings, especially for Tsunamis generated by near-source and atypical one like submarine landslide, volcanic eruptions, coastal subsidence etc., explained the director. Focus is on research and development efforts towards advanced procedures such as water level inversion, real-time inundation modelling, use of near-field GNSS - global navigation satellite system, measurements for real-time rupture characterisation and 3D mapping of vulnerable coastal areas.
ITWES advanced computational and communication infrastructure helps receive and analyse real-time data from hundreds of sensors for timely advisories to vulnerable communities. “Yet, success of a warning is measured by what actions people take once the respective authorities issue a public warning. Developing and maintaining a culture of self-evacuation is important for saving lives, especially in case of near-source tsunamis which can reach the coast in minutes, leaving little time for warnings even with advanced technologies,” said Dr. Kumar.
