From a UC Santa Cruz Press Release:
The infamous Indian Ocean tsunami that struck on December 26, 2004, caused tragically high mortality–from 10 to 90 percent of the population at various locations. Yet in 1930 a tsunami of similar size, generated by an earthquake near the Ninigo Islands, struck northern Papua New Guinea and killed just 0.1 to 1 percent of the population on the coast there.Why were these islanders living earlier in the century better protected?…
Tsunami expert Simon Day proposes that oral traditions made the difference.Day and colleagues were investigating historic tsunamis in the Bismarck Sea, north of Papua New Guinea when they ran into this idea. In conversations with local leaders, they encountered stories about past tsunaic, that Day was able to link to actual geologic events.
It became apparent that oral traditions were going back 500 years … The stories contained information about how to recognize when a tsunami was about to come, such as falling sea levels, and told how people should take action. That’s the reason why casualties [in 1930] were so low.
With further research, Day has been able to demonstrate that casualties due to tsunamis are significantly higher in areas into which people have recently migrated, and thus lacked the appropriate, adaptive, local lore. The Christmas event in 2004 was one of the prime examples of this. Examination of videos from Thailand clearly showed that people were unable to interpret the warning signs of an oncoming wave.[source]