I’ve read reports that the tsunami in Japan was 33 feet high. How far inland would a 33 foot tsunami go?
it depends on the elevation of the land.
in this case it went in 6 miles as i recall.
The short answer is that it will go inland until the elevation of the land is higher than the tsunami. A lot of Japanese coast is essentially flat until you get to the mountains.
Here’s a satellite photo before and after the tsunami. Especially look at the upper part of the images, between Abukuma River and Matsukawa-ura Bay. In those photos the flooding went as far as 4 kilometers inland.
actually has more to do with the energy still left as it hits the nominal shore but for all intents and purposes, the above post is correct.
when we were reading up on tidal waves in high school and college, the books always gave ideal examples wherein at mid-ocean, the tsunami would propagate outwards with a wave height of only 10 inches but at the speed of sound. as it approaches land, its speed decreases but its height (amplitude) rears to monstrous height. it should reach more than 300 feet when it hits shore but that’s a very ideal case wherein its speed drops to zero right at the shore and the wave breaks. so a 300-1000 foot ideal tsunami is supposed to weak havoc only in the near-shore.
but in the case of banda aceh and japan, the wave still had sufficient energy at the shore so that it didn’t have to rear to a great height and break. what happened is the wave frequency just compressed without an increase in ampitude, and not much reduction in speed. in short, it’s not just a one-pulse wave hitting land but a solid wall of water.
japan also got lower in the tsunami area because of the earthquake. when the tsunami came the land wasn’t as high as it used to be.
there are previous dry land areas that now flood at high tide.
Actually the tsunami when it hit some parts of the shore was recorded at about 38 METRES high, which is 125 feet.
My husband was involved in search and rescue. He said they went into a five storey building that had smashed windows and sand on the top floor ceilings. He also said that in some areas the devastation went back six or seven kilometers (usually along river courses.)