Any tsunami video I look at barely looks like a 20 feet wave hitting shore. But wikipedia tells me there have been dozens of 100+ feet tsunamis even in the last 10 years.
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To be fair there is *some* footage of tsunami as the stereotypical “wall of water” near shore as they are popularly portrayed, but they do break before landfall
[here](https://www.youtube.com/watch?v=WO7TZFBAlaE)
[here](https://www.youtube.com/watch?v=eQyAESpixF8)
[here](https://www.youtube.com/watch?v=EomuVQjh9nc)
these are the *smaller waves* a wave of 100+ foot breaks long before its near any beach for resons already explained but a common misconception is that Runup=the hight of the wave, often when tsunami are quoted as being 100+ foot the wave itself would have been the same size as the area where its runoff was around 20 to 30 foot but some quirk of the landscape exaccebated the wave.
[This](https://www.researchgate.net/profile/Franck-Lavigne/publication/236341733/figure/fig4/AS:668351521112065@1536358828070/Runup-height-of-51-m-asl-measured-on-a-cliff-near-Leupung-on-the-west-coast-location.png)
shows an almost inconcevable runup of 51m/167ft. Does that mean the surge came ashore in the “typical” tunami tide but 51m tall? if you look at the picture you can make a few guesses as to what may have happened here. Tsunamis are not waves in the conventional sense we understand them. If a normal wave is a car, a tsunami is a train. if a car crashes into a wall it imparts a momentary spike of force before stopping. A train is hundreds of tons of metal. its going to plough through and keep going.
Now take that analogy and apply it to water, you now have multiple speeding trains all crashing into a wall and since its water its just going to keep piling up and up and up. looking at the image the line of scour marking the runup stops roughly at the lowest point of the rock. So its probably a safe guess to say what happened is the tsunamis piled up behind the rocks blocking them then overtopped and flowed over it. The maximum hight of the tsunami here is 51m/167ft. but that doesnt mean the wave or surge itself was that high. Just that in this area it reached that high
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