Sadly parents let their kids do this and some have lost their lives.
So my question was, why would a Tsunami of the same height be that much worse. And in comparison to the destruction of the earthquake in general here.
When people talked above about the long wavelength of a tsunami, they mean it doesn't crest and possibly break in seconds like a surface wave. It can keep building for many minutes and continue to flow inland after the crest.
Look for some tourist video of the 2004 tsunami that flowed over islands in Thailand. It looks more like a river or levee breach flooding over the whole field of view. In steeper coastal terrain, the wave can sometimes be funneled or focused into a narrower port or valley and then reach much higher elevations than you would expect.
