Tsunami early warning system at work:

How far is Sri Lanka prepared ?

by Indeewara Thilakarathne

Until the Asian Tsunami hit the island, Sri Lanka had been considered as one of the few countries on the globe out of the danger zone of the natural disaster, particularly, owing to its strategic location in the Indian Ocean, far from major platonic plates.

However, this sense of false safety from natural disasters was shattered in the aftermath of the devastating Tsunami that claimed scores of lives, in addition to causing serious structural damages to the country's physical infrastructure, making some of the coastal townships unreachable for days. It was widely predicted that some of the worst calamities, such as the Peraliya rail disaster which is now considered to be one of the worst rail disasters the world had ever witnessed, could have been averted, if Sri Lanka had an early warning system in operation.

On the other hand, the country's foremost institution, Meteorological Department and the plethora of scientific institutions responsible for monitoring seismic activities were either ill-equipped or not alerted enough to receive vital data from Hawaii Earthquakes Monitoring Centre which has kept vigil on the seismic activities around the globe and earthquakes in deep sea, likely to generate a Tsunami.

By now, dust has settled over the issue. Instead, hot issues such as war and peace and the long-held Norwegian brokered peace process occupy a centre stage in public discourse. It is, however, pertinens to ponder on whether Sri Lanka has formulated a contingency plan together with an effective and efficient early warning system that would prevent the recur of the tragedy that the country witnessed in the aftermath of the Tsunami, or are we to perish collectively ?.

According to the Director (Technology and Mitigation) of the Disaster Management Centre (DMC) U.W.L Chandradasa, Sri Lanka has already set up an islandwide network of Tsunami Early Warning System, (TEWS) and currently operates via cellular phones. In addition, DMC has conducted awareness programmes covering the entire coastline that is prone to Tsunami. The DMC which functions under the Ministry of Disaster Management and Human Rights has also taken many steps to ensure the safety of the public, in the event of a natural disaster, by an early warning of the impending disaster.

Putting up Tsunami warning signboards in Tsunami-prone areas, guiding the visitors and tourists to safe areas in the immediate vicinity, is a step taken in the right direction. DMC is of the view that Sri Lanka is ahead of most of the Asian countries in terms of raising public awareness on the disaster management and TEWS, due to its high literacy rate.

The DMC is now in a position to inform the public of an impending natural disaster or a Tsunami, within a short time and issue warnings through its islandwide network. The network operates through DMC's representatives at district and provincial levels and in collaboration with the police. Special arrangements have been made in areas such as Ampara to inform the public through officers who would visit the areas prone to Tsunami on bicycles.

Well-crafted plan

A well-crafted contingency plan has already been put in place to be activated in case of a disaster. The Emergency Operation would be carried out with the aid of the armed forces, police and other relevant agencies at national and all sub-levels and the people in the Tsunami prone areas would be evacuated to designated safety areas in their immediate vicinity.

The Tsunami warning is currently issued by Meteorological Department which has now received real-time-date from major Earthquakes Monitoring Centres including Hawaii and Japanese centres. It is in a position to issue early warnings of earthquakes which occurred in the seismically active region of Indonesia that could trigger a Tsunami.

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Tsunami Watch and Warning Determination

The objective of the PTWS is to detect, locate, and determine the magnitude of potentially tsunamigenic earthquakes occurring in the Pacific Basin or its immediate margins. Earthquake information is provided by seismic stations operated by PTWC, ATWC, the U.S. Geological Survey's National Earthquake Information Center and international sources.

If the location and magnitude of an earthquake meet the known criteria for the generation of a tsunami, a tsunami warning is issued to warn of an imminent tsunami hazard. The warning includes predicted tsunami arrival times at selected coastal communities within the geographic area defined by the maximum distance the tsunami could travel in a few hours. A tsunami watch with additional predicted tsunami arrival times is issued for a geographic area defined by the distance the tsunami could travel, in a subsequent time period.

If a significant tsunami is detected by sea-level monitoring instrumentation, the tsunami warning is extended to the entire Pacific Basin. Sea-level (or tidal) information is provided by NOAA's National Ocean Service, PTWC, ATWC, university monitoring networks and other participating nations of the PTWS.

The International Tsunami Information Centre, part of the Inter-governmental Oceanographic Commission, monitors and evaluates the performance and effectiveness of the Pacific Tsunami Warning System. This effort encourages the most effective data collection, data analysis, tsunami impact assessment and warning dissemination to all TWS participants.

Tsunami Warning Dissemination Tsunami watch, warning, and information bulletins are disseminated to appropriate emergency officials and the general public by a variety of communication methods.

Tsunami watch, warning and information bulletins issued by PTWC and ATWC are disseminated to local, state, national and international users as well as the media. These users, in turn, disseminate the tsunami information to the public, generally over commercial radio and television channels.

The NOAA Weather Radio System, based on a large number of VHF transmitter sites, provides direct broadcast of tsunami information to the public.

The US Coast Guard also broadcasts urgent marine warnings and related tsunami information to coastal users equipped with medium frequency (MF) and very high frequency (VHF) marine radios. Local authorities and emergency managers are responsible for formulating and executing evacuation plans for areas under a tsunami warning.

The public should stay-tuned to the local media for evacuation orders, should a tsunami warning be issued. And, the public should NOT RETURN to low-lying areas until the tsunami threat has passed and the "all clear" is announced by the local authorities.