Indonesia was hit by two destructive tsunamis in late 2018 – the first event was the Palu and Donggala tsunami of 28 September 2018 following the 7.5 magnitude earthquake in Central Sulawesi that killed about 1252 people. The second was the Sunda Strait tsunami of 22 December 2018 following an eruption and partial collapse of the Anak Krakatau volcano that killed about 426 people.
In commemoration of one year of the Palu and Donggala tsunami, UNESCO’s Intergovernmental Oceanographic Commission (IOC) in collaboration with the Coordinating Ministry for Maritime Affairs (CMMA) and the Indonesian Agency for Meteorology, Climatology, and Geophysics (BMKG) with support from several other national and international partners orgnised an International Symposium on” Lessons Learnt from the 2018 Tsunamis in Palu and Sunda Strait” at BMKG, Jakarta, Indonesia during 26-28 September 2019. More than 270 participants from 24 countries attended the symposium. A total of 32 talks, 25 posters and 25 photo exhibits were presented at the Symposium covering scientific findings from the International Post Tsunami Survey Teams (ITST), critical issues surrounding warning systems and possible improvements.
After the 26 December 2004 tsunami, much progress has been made in the establishment of IOC-coordinated regional tsunami early warning systems in the Indian Ocean, Caribbean and Northeast Atlantic & Mediterranean. The three systems join the system that was already operational in the Pacific. While tsunami warning systems have proven to be effective in mitigating the impact of tsunamis globally, Palu and Sunda Strait tsunamis highlighted the challenges that we continue to face.
The symposium highlighted that tsunamis generated by near-field, atypical sources (coastal subsidence, landslides and volcanic flank collapse) are very complex from an early warning perspective, and emphasized the urgent need to update hazard assessments, strengthen warning capabilities and enhance community preparedness to deal with such events. Managing and improving tsunami warning systems require effective governance mechanism and policies at the national level.
The symposium appealed to countries to strengthen warning systems through new observing technologies such as undersea cables and Global Navigation Satellite System (GNSS), share more of “real-time” data from their observing networks and implement new monitoring techniques for tsunamis from atypical sources. It is important to review and revise national warning dissemination mechanisms and standard operating procedures, to be able to deliver timely, simple and actionable messages to the public.
Developing and maintaining a culture of self-evacuation is important for saving lives from locally generated tsunamis. The symposium stressed the important of community awareness and preparedness to enable rapid appropriate response to both official warnings and to the natural signs of a possible tsunami. Performance based community recognition programs such as IOC UNESCO Tsunami Ready can also contribute to enhance tsunami preparedness.
The symposium reiterated the importance of post-event surveys, and the need to conduct them as soon as practically possible based on well-established protocols and national regulations. It is also important to document past tsunamis for the benefit of future generations through eye witness interviews, especially for areas with few historical tsunamis and no quantitative observational records.
A publication by on the “Limitations and Challenges in Tsunami Early Warning Systems: A Case Study of 28 September 2019 Palu-Donggala Tsunami” was launched during the symposium. Presentations from the Symposium will be made available at http://www.ioc-tsunami.org/palu.