The tsunami which recently devastated Indonesia’s island province of Sulawesi has prompted review into existing and theoretical engineering solutions for preventing the impact of deadly tsunamis. The most obvious solution which was used by ancient civilisations is to build a wall. Still used in modern engineering, this form of protection has proved largely ineffective at stopping major tsunamis and as such, researchers are attempting to find other solutions. One idea by a researcher at the University of Ottawa is to weaken and dissipate the waves at sea, reducing its intensity when it reaches land by creating artificial islands and reefs. Another interesting idea suggested in a 2017 paper is to use acoustic-gravity cannons to disrupt tsunamis and reduce their impact on the shore. This is not yet possible given the large amount of energy required to generate the acoustic-gravity waves. Purpose-built tsunami-proof shelters have also been designed and implemented in some places. Some of these are even designed to float to ride out the wave. (read more here).