Tsunami over-reaction inevitable - Disaster Mitigation Director

By Ranil WIJAYAPALA

The people’s reaction to tsunami alert signalled in the early hours of last Sunday was chaotic. Some people panicked and overreacted when tsunami watch alert was issued after an underwater earthquake, measuring 7.7 on the Richter scale, off the coast of Andaman and Nicobar Islands.

This ‘tsunami watch’ alert was signalled by the US-based Pacific Tsunami Warning Centre (PTWC).

The Regional Tsunami Watch Bulletin was issued to India, Indonesia, Sri Lanka, Myanmar, Thailand and Malaysia at 01.04 hours Sri Lanka Time-18 minutes after the quake. (00.46 hours)

A second message called off the alert 44 minutes later. So by 01.48 hours everything should have been back to normal in Sri Lanka. But, the situation did not return to normal even after tsunami watch alert was called off.

While one section of people were following the instructions given to them, some overreacted to the situation. Therefore, it was obvious that something went wrong with our tsunami alert system that day creating a panic situation in the country.

With the objective of finding out what went wrong with the alert system, and to probe into the country’s preparedness to face future tsunami situations, the Sunday Observer interviewed W.U.L. Chandradasa, Director, Disaster Mitigation of the National Disaster Management Centre.

In his interview, Chandradasa emphasised the fact that some people panicked as they received the tsunami watch alert as an evacuation message. The system of alerting should be changed into giving the correct message at the right time.

He said if the people follow only the messages issued by the Disaster Management Centre there won’t be unnecessary panic situations.

Following are the excerpts of the interview:

Q: Is there a simple way of alerting the people on tsunami warnings in Sri Lanka?

A: Yes, we have 55, tsunami towers across the coastal belt. When we receive the tsunami warning we identify the exact area that will be affected. This time we identified only the eastern province and Hambantota, Galle and Matara. According to the location and the strength of the earthquake, we decide the areas that will be affected by the tsunami.

We normally issue two messages. One is an alert. That is to inform the people that “something” has happened and there could perhaps be a tsunami, but that is not for the people to leave their houses. The second message is sent when exactly we have decided that there is tsunami. That is a message to evacuate the people from the areas which will be affected by tsunami.

Q: What happened on last Sunday? The alert message was rather confusing to the people?

A: We sent an alert and the Police started evacuating the people. The Police should have kept the people informed and not evacuate them. There was “miscommunication”. As soon as they got the message from the Meterological Department on the possibility of a tsunami, the police started evacuating the people. They failed to understand the difference between the ‘alert’ and the ‘evacuation’.

This situation has to be corrected in the interest of the people.

Q: How are you going to rectify this situation?

A: We decided not to issue the alert order to the Police but only the evacuation message.

Q: How you are going to educate the people on this issue?

A: We have launched the awareness program. The people should listen to the messages issued only by the Disaster Management Centre and not to any other messages. We are giving the official warning. People should act on the warning. Actually this time a lot of people listened to it. They didn’t withdraw until we told them. We have to give some more training to the people. At the same time we are going to inform the Police how to act on such instances. People got the message but some overreacted due to the bad experience they had earlier.

Q: But the people in other areas also panicked?

A: Normally the message is not delivered to other areas.

But all the Police stations got the message. They do not limit it only to the Police stations in the coastal areas. They feed it to their communication network. People receive the message from the Police. For example, those in Colombo who will not be affected also got the message and panic. So we have to further educate the people on this situation.

Q: Is there a simple system of issuing the warning?

A: People will not be able to identify the areas that would be affected by the tsunami. They will have to depend on the alert messages. These messages come from the Tsunami Early Warning Systems. Even scientists cannot identify the tsunami danger. Normally, we identify the tsunami when there is an earthquake exceeding the 7.5 magnitude on the Richter scale. But this depends as on the movement direction that the tsunami creates. If it was vertical in an up and down direction there would be tsunami. But if it was a horizontal there won’t be tsunami. Normally no body can identify the movement until they receive the information. That can be done only by a scientific organisation. Here they measure the sea level movement. It is only from that they could predicts tsunami. Even for a scientific organisation it takes at least 20 minutes to confirm it. They have to identify it from the floating boeing’s in the sea. From the floating boeing satellite communication they collect the information on the movement of the sea waves. Changes in waves are indicative of tsunami. If there is no change in waves there is no tsunami. It takes at least 20 minutes to decide the possibility of a tsunami.

Q: After the 2004 tsunami the people have the tendency to ignore the tsunami warning. How does the DMC plan to educate the people on tsunami situations?

A: We prepare ourselves for various types of disasters including tsunami. We do the annual drill to educate people on as to what they should do, where they should find shelter in the event of a tsunami warning. We have done this on the coastal belt annually. On December 26 we have National Safety Day. We have plans to hold it on the coastal belt. We will keep on reminding the people about the threat. We conduct the drills in individual villages once in three months to prepare them for tsunami warnings.

Q: Soon after the 2004 tsunami a buffer zone was created in the coastal belt restricting construction of buildings. What happened to the buffer zone? Is it still effective?

A: Initially, they decided to have a two hundred meter buffer zone. Later it was to be reduced to hundred meters. Then again they decided to have 35 to 100 meter buffer zone. The buffer zone was not decided on the height. If you are on high ground you do not entertain any fear of tsunami. People also want safer areas demarcated.

There is no scientific basis for it. We have got a survey done along the coastal belt where we have given half meter contours. Based on the contours we have got the Coast Conservation Department to do a mapping and see what are the areas that are going to be inundated in the case of tsunami. So we get the Post Tsunami Advocate Study and demarcate the areas that could be affected by the tsunami. Now those areas have been demarcated as than buffer zone. That is what we will be developing and it will be released to the Coast Conservation Department to declare the as buffer zones. Of course, in the Eastern province the safer areas will be far away from the coast.

Q: How are you going to implement that system?

A: We are going to implement it through the Coast Conservation Department. The CCD has the mandate to declare the buffer zones in association with the UDA.

Q: How long would it take?

A: Now we are preparing the grid maps. It will be completed by end of this year. So we can give the map to the CCD and the UDA. In keeping with the maps they could include their planning concepts after considering the grid maps and declare the buffer zones.

Q: What will happen to the buildings in these buffer zones?

A: Now they are observing the 100 metre rule in the Eastern Province which is much safer now. In other areas 35 metre rule may be ok. In some areas there could be changes. They are not allowing any constructions within those areas. But with regard to other areas marked in the inundation maps, we can discuss with the residents and explain to them the danger they will have to face. We should also advise a system for them to voluntarily move out of their premises.

Q: The frequency of earthquakes around Sri Lanka has increased. The country experienced a number of tremors. Will there be a disaster affecting Sri Lanka?

A: Actually we have observed during the last three years that tremors had sounded off and on. We still don’t have equipment to monitor the exact locations of these tremors. The Geological and Mines Bureau is handling this issue. Even if there is a tremor we don’t know where it had occurred. Presently, they are in a process of acquiring equipment to measure the local tremors and find out where they have occurred. We have got German funding for that. There is special equipment to locate the long distance earthquakes and tremors. That is to locate regional level tremors and earthquakes. For instance, if there is a tremor in India it can locate it. It was given to us by the US Government. We don’t have a system to monitor the tremors and earthquakes happening locally. We must have three stations to do it locally. Therefore, we have the problem of locating those earthquakes correctly.

Q: What is the assessment on the frequency of tsunamis affecting the country?

A: According to the way it had happened and also based on historical data they have calculated that it could happen once in six hundred years. The Japanese scientists have made these calculations. Earthquakes cannot be predicted. But when you go through the past records, sometimes they could observe some sort of frequency level. On that basis only they can predict the frequency of earthquakes. That is how they have calculated that it could happen once in six hundred years.

Q: Does it mean that there is no necessity to be on alert about tsunami for quite a long period?

A: No. It is only a prediction. But it could happen at any time. Earthquakes cannot be predicted. The plates formation are taking place. So we can’t predict as to where the next earthquake occurs. Therefore, we can’t just be relaxing. We must be on alert. It is like floods! It could be floods today and again in two or three days time there will be floods. we don’t know how the nature is changing. We have to keep the people ready on that. We didn’t expect frequent earthquakes in these areas earlier. There were five or six earthquakes during the past two years that could trigger tsunamis. There was one in Andaman and one in Pakistan. They are happening.

Q: What could be the mechanism?

A: First we have the police communication. Then we have these towers and the Armed Forces camps which we keep informed and then the GA and the Grama Sevakas. We also have a SMS message system. We can send SMS messages and also cell broadcast it. We have programmed it in such a way that we could transmit it to one district or all the districts. We also could convey it through the Dialog. We have a system here to do that. Even this time we send SMS and cell broadcasting messages to various people on tsunami alert and evacuation of people. That is the system we have adopted.

Q: Won’t here be any confusion among the people by following these methods?

A: Actually this time there was no such confusion. But people overacted. We will have to minimise it. Some people are likely to overreact when they hear the sirens. The natural tendency is to withdraw when they hear the siren.

It happens always. But we want to make sure that people could distinguish between evacuation message and sirens. Sirens can be heard over a two kilo metres distance.

But in the case of message it is less. You may hear the sirens, and not the message. Therefore, we have to think about as to how to give the message correctly.

When they hear the siren, people know something is happening! They panic and start moving.

They won’t wait till the message comes. That is the problem. Specially children and elderly people start moving because there is no time for them to take the children and elderly people away if tsunami is coming!