# To what elevations did the tsunami penetrate in Japan? I have see some data on how far but not how high.

I live in a coastal area of California that is fairly flat. I understand that tsunamis can penetrate great distances inland in flat areas.

The highest wave height cited in the ref below is 7.3 meters. The height of the wave(s) is probably a decent approximation of the maximum elevation reached; higher or lower depending on geometry of the inundated area. The actual value will probably have to wait for additional efforts and investigation.

Some news sources are reporting wave heights as great as 10 meters (33 feet).

This doesn’t work as an answer. This would work as an answer for the elevation at the coast where a wave would start to penetrate but not for the elevation it would end at. Tsumanis don’t act like daily tides. The wave is pushed in and up by the waves following and that is the data I’m looking for.

Yes, you’re right, I was just thinking it would be a first approximation. I did not see anything as I searched that suggested an actual measured maximum elevation for the water’s reach.

I am told by the engineers in my office that a 7.3 m wave will reach a higher elevation than 7.3 m. see my answer below for my approximation of the elevation the wave penetrated.

Wave heights reached more than 20 feet in some places along Japan’s coast. Obviously, since most of Japan’s elevation is 1000-3000 feet, this is why the tsunami was so devastating. The following link has some pretty handy diagrams and maps, while the secondary link has Japan’s geographical characteristics. Compare them side by side.

I have been contemplating this question too. Here is what I did:

Looking at the pictures from Japan, I located the landmarks on Bikely.com (a site where you can plan a bike trip but it also tells you elevations). Looking at the landmarks in Japan on bikely I concluded that the wave reached and destroyed houses 1.7 km from ocean at an elevation of 40m. It is possible that it got higher but the landmarks that I measured were at that hight. It seems that trees do a lot to decrese the impact of tsunami. So if there is a forest between you and the water, the elevation the wave reaches will be lower than if the wave was not there. My conclusion is sin trees.

In short, 1.7km at 40m w/o trees.