Lessons from the Sri Lanka tsunami warnings and evacuation of September 12-13, 2007

The tragedy of the 2004 Indian Ocean tsunami was the absence of any official warning. The September 12th Bengkulu earthquake shows that this is unlikely to be the case in the future. We have seen that the new institutions created since the 2004 tsunami have the will and the capacity to act. What we must guard against now is indifference to warning; of populations that refuse to evacuate in the face of real danger.

The prediction of a tsunami is an inexact art that must be practiced in conditions of highly imperfect information and time pressure. In the Pacific Basin, which has had the most experience with tsunamis, 75 per cent of all warnings are false. But this does not cause major harm because the false warnings are contained within the official system and do not get through to the general population for the most part.

Tsunamis are rapid-onset hazards. It took 90 minutes for the 2004 India Ocean tsunami to reach the Arugam Bay-Panama coast in Eastern Sri Lanka. In September 2007, the earthquake occurred at 1110 UTC or 4:40 PM Sri Lanka time. Tsunami Bulletin 001 issued by the Pacific Tsunami Warning Center at 1124 UTC (4: 54 PM Sri Lanka time) projected arrival times of over three hours, with the shortest being to Devundara (3:37 hours after the earthquake, at 8:13 PM Sri Lanka time) and the longest being to Jaffna (5:15 hours). Colombo, which was marginally affected even in 2004, was projected to be made contact with at 8:45 PM Sri Lanka time (4:05 hours after the quake). This was because the origin was well to the south of the northern tip of Sumatra where the 2004 Indian Ocean tsunami originated and because the earthquake was 10 times weaker than that in 2004.

As much as possible of the limited time must be allocated to (a) decision making by authorized persons at the national level about the issuance of watch, warning or evacuation messages; and (b) decision making and action at the level of communities, including evacuation if appropriate. This means that the time taken to communicate the watch/warning/evacuation messages must be minimized.

This does not mean, however, that evacuation orders should be given as quickly as possible. Ideally, such strong measures will be targeted, for example to the Matara district which was foreseen to be the first point of contact. Even there, closing roads would be done as close to 8 PM as possible, because people need the roads and public transport to effect an orderly evacuation.

Decision-making at the national level

As stated above, the issuance of tsunami watch/warning/evacuation messages is an inexact art, based on imperfect information. Given the massive costs associated with evacuation orders (not only in terms of lost productivity but also in terms of deaths, injuries and other negative outcomes that can be caused), government must be the sole authority. Given the certainty of blame if a tsunami does hit and an evacuation order had not been issued, there is likely to be a bias toward over-use of warnings and evacuation orders especially in a culture that does not value economic activity highly.

It is important that procedures be established not only to make considered but quick decisions about watch/warning/evacuation messages, but also to counter balance the bias toward excessive use of warnings and evacuation orders. This includes clear decision rules and assignment of responsibilities. A multi-stage and multi-party decision process (for example having one center for hazard detection and monitoring (Sri Lanka Meteorological Department) and another for public warning (Disaster Management Center) may not be the best way to improve decision making and minimize time.

When time is short and ambiguity can be deadly, it is best to stick to prepared texts and formats. Standard message templates in all three official languages preferably generated using the Common Alerting Protocol (CAP) software have been recognized as a high priority by the Ministry of Disaster Management and Human Rights and the Disaster Management Center.

Communicating messages to first responders and media

It appears, from anecdotal evidence, that the tsunami hazard information center (Met Department) received large numbers of phone calls from the media when word got around that a potentially tsunamigenic earthquake had occurred on the Indian Ocean side of Indonesia. In many cases, senior officers who should have been communicating the scientific evidence to key decision makers at the DMC and the Ministry were being called directly.

This practice is problematic for two reasons:

1. It eats up the time that should be used for considered decision making on whether or not to issue national-level watch/warning/evacuation messages. Time spent on the phone is time not spent on analyzing or communicating the evidence to the relevant authorities;
2. The unstructured format of a journalist-initiated phone call can lead to misunderstanding. For example, some journalists may not know the difference between an alert and a warning. This format also does not leave a record in case there is a need to review it at a later time.

Expressing concern about talking to journalists in the aftermath of a tsunamigenic earthquake does not equate to a recommendation that no one should talk to the media. What is required are:

1. A reliable and fast method of communication (e-mail, fax, telex, or even a taped telephone voice message) with journalists in all three official languages. Messages should be sent to designated numbers and e-mail addresses, preferably using automated procedures.
2. Journalists who call the designated number (preferably in a hunting configuration that can handle multiple simultaneous calls) should be able to hear a taped message.
3. If journalists require additional information they should be able to call a designated spokesperson, whose sole responsibility is to talk to the media. All conversations should be taped.

The point is to give more information faster and in better formats. Shifting away from the current unstructured modes to a structured mode will allow this to be done. Involving journalists in the process of restructuring the communication system of the Met Department will help improve it and will also serve to educate journalists about it.

Multiple media such as fixed and mobile phones, SMS, fax and the Internet should be used. Redundancy improves reliability. Using CAP enabled media will help streamline the process and expedite the messages. Where character limitations exist, as in SMS, the short message can be used to direct the recipient to the place where the complete message can be obtained.

The LIRNEasia-Sarvodaya Last Mile HazInfo pilot project showed that the most efficacious method of communicating to first responders would be through addressable satellite radio sets plus GSM/CDMA phones. If the government wishes, these instruments can be temporarily loaned to government for trials as decided at a recent meeting convened by the Ministry and the DMC.

Decision making at the community level

The Sarvodaya-LIRNEasia community centered disaster risk reduction approach places greatest weight on decision marking and prior preparation and training at the community level. In this model, each Sarvodaya village will have an ICT guardian who can communicate bidirectionally with the Hazard Information Hub (HIH) of Sarvodaya. The objective of the next stage of work within Sarvodaya is to equip 1000 advanced villages belonging to Sarvodaya with the knowledge and training to devise and implement emergency response plans at the village level and to have the ability to communicate information to and from the HIH.

In this model, the community will be alert and ready to respond in the optimal way to any watch, warning or evacuation message issued by the government. The HIH will amplify the government’s message and prior training and preparation will enable to community to respond in the most productive manner to a government message. The objective of those working at the national levels and designing and operating the communication systems should be to give the community unambiguous information and the longest possible time to take appropriate action.

Community preparedness also helps the national-level decision makers. If they know that the community is prepared and capable of responding quickly and in an orderly manner to an evacuation order, they can delay the “strong measures” until absolutely necessary. It is when that confidence is lacking that there is a tendency to issue warnings and evacuation orders too early. It is perhaps because of this that Thailand did not join Sri Lanka and Bangladesh in issuing evacuation orders after the Bengkulu earthquake.

Minimizing the false

In the disaster risk-reduction field, false warnings are not seen as being a result of malice or incompetence. They are simply artefacts of the inexact art of predicting the onset of hazards. Professionals know this, but the general public does not. If they are subject to too many false warnings, the general public will not respond even to true warnings.

Now that we have gotten over the problem of issuing no warnings, we have to address the problem of reducing false warnings. Effective design of protocols at each stage of the warning chain and committed implementation combined with a passion of continuous improvement will help us reduce the false and realize the promise of early warning to save lives.

Rohan Samarajiva, Ph.D.
Project Director, Last Mile HazInfo Project &
Executive Director, LIRNEasia
13 September 2007

The final report is available here (PDF):

WEBHAMUVA: Report on People’s Consultations on Post Tsunami Relief, Reconstruction and Rehabilitation in Sri Lanka

The findings from the report indicate that people are dissatisfied with the pace of reconstruction and rehabilitation. Most of the tsunami-affected spoken to have yet to recover their normal lives in terms of livelihood, permanent housing and their sense of safety and security. The feeling of helplessness and despair is quite prevalent especially when people do not have the capital or means to engage in sustainable livelihoods. Needs assessment from the donors has not been very effective because there seems to be a large discrepancy between what people need and what is supplied to them. Starting from housing issues to lesser significant things like utensils and victuals, what is supplied is often not what people want or need.

The tsunami seems to have had an impact that goes beyond economics and has reconfigured the social and cultural lives of those affected. The forced sharing of space in camps and flat-type housing has brought together people from different social backgrounds which have generated some apprehension and friction.

The program was activated in a number of Sarvodaya Service villages located in the Tsunami-affected districts. Trained staff from Sarvodaya visited villages in those districts and asked inhabitants about the effect of the tsunami on their lives, their views on the reconstruction and rehabilitation in their area, and about their current problems and needs. The answers were recorded in the local language and was later transcribed and translated into English. The reports from the villages were then published on www.webhamuva.org, which can be accessed by anyone from around the world.

Twenty four reports in English from six Tsunami affected districts (Colombo, Kalutara, Matara, Hambantota, Ampara and Trincomalee) were produced. Sinhala versions from three districts were also made available on the website as PDF downloads.