Some coastlines with earthquake zones off-shore
can act as “tsunami magnets”, to produce devastating flooding as much as 50% deeper than expected. In this animation, the trough of the tsunami
wave propagates towards the shoreline. And the wave energy is focused and amplified. The focal point where the tsunami wave is
most amplified can be located on-shore or off-shore, depending on the distance of the
earthquake origin from the shoreline. This explains the unexpectedly large runups
observed for some tsunamis such as the great Japan tsunami of 2011 or the Java tsunami in 2006.