Recent occurrences of serious tsunami damage and the future challenges of tsunami disaster risk reduction

With a total of 251,770 casualties and US$280 billion in damages, the loss inflicted by tsunamis between 1998 and 2017 was one hundred times higher than that experienced during the previous decade (1978–1997). The processes of disasters following tsunamis have also become more complex with global impacts. The broad economic and political consequences of the 2011 Tohoku earthquake and tsunami encouraged the global community to consider the problem of “cascading disasters”. We can categorized the cause and damage due to the 2011 tsunami with incentive and predisposing factors, impact as compound disaster. We also proposed and developed various tsunami fragility functions as essential tools to assess and mitigate damage such as casualties, house/building, marine vessels, pedestrian bridges, road bridges and aquaculture rafts. The process of cascading disasters still remains as major issue and should be studied together with the factors of interdependencies, vulnerabilities, amplification, secondary disasters and critical infrastructure and spin-off effects. Another important issue concerns non-seismic tsunamis, such as those that impacted Palu and Sunda Straight in Indonesia in 2018. These events demonstrated the difficulties and remaining problems regarding tsunami warning and evacuation and the difficulties of real time monitoring and detection. Since tsunamis are low-frequency, high-impact natural hazards, interdisciplinary research on risk perception, awareness, memory and lessons becomes critically important. The process of sharing tsunami experiences underwent a transformation in the form of digital archives and new media in response to the needs and opportunities for disaster risk reduction (DRR) in the 21st century. Last but not least, this paper highlights the roles of museum and memorial halls in order to share the experiences of natural hazard-related disasters necessary to inform disaster mitigation.