# Tsunami waves vs. 60 foot cliff **URL:** \ **Category:** Factual Questions\ **Created:** [August 18, 2013, 5:11pm UTC](https://boards.straightdope.com/t/tsunami-waves-vs-60-foot-cliff/666572 "2013-08-18T17:11:33Z")\ **Posts on this page:** 11\ **Page:** 2
**Author:** ![snowthx](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/snowthx/32/10660_2.png) [@snowthx](https://boards.straightdope.com/u/snowthx)\ **Post date:** [August 19, 2013, 9:30pm UTC](https://boards.straightdope.com/t/tsunami-waves-vs-60-foot-cliff/666572/21 "2013-08-19T21:30:53Z")
I dont know if this is relevant to the OP, but I recall seeing some news footage from the 2011 Japan tsunami when it hit Oregon and NorCal - they were showing a small beach with a cliff behind it getting inundated in a matter of minutes. Of course, the cliff was OK since we had the footage (the camera was on top of the cliff). It seemed like the water rose and fell like a bathtub against the cliff - it was not a wall of water crashing against it - wave face against cliff face. That would be spectacular to witness, but likely more destructive. The beach was wrecked, but the cliff and cliff-top were OK. I think the orientation of the beach and cliff and local bottom conditions, and tides, all play a factor, so no telling if the same thing applies for the OP. Granted, the footage showed what looked like about a 10 foot sudden rise in the ocean, not 60 feet. I think also the footage of the destructive waves we are familiar with rolling across the Japan countryside came in across nearly level coastal plain - they did not roll over a 60 foot cliff before heading inland. Now, if a 60+ foot rise in the ocean were to happen suddenly, I could see it breaching the cliff top, and then you would have a problem. Probably many problems. ---
**Author:** ![Mangosteen](https://avatars.discourse-cdn.com/v4/letter/m/6a8cbe/32.png) [@Mangosteen](https://boards.straightdope.com/u/Mangosteen)\ **Post date:** [August 19, 2013, 10:26pm UTC](https://boards.straightdope.com/t/tsunami-waves-vs-60-foot-cliff/666572/22 "2013-08-19T22:26:03Z")
> [@md2000](#): > > I agree, sounds amazing - but having lived in the middle of grand wilderness before, it’s not for everyone. Enjoy it if it’s your taste, but there’s a reason many people move to the big city. > > * * * Not really wilderness. The homesite is 7 miles north of Hilo, the second largest city in Hawaii, pop. 45,000+. We’re less than a mile off the main north-south highway. The lack of infrastructure is because only a few years back the entire area was sugar cane fields. ---
**Author:** ![Mangosteen](https://avatars.discourse-cdn.com/v4/letter/m/6a8cbe/32.png) [@Mangosteen](https://boards.straightdope.com/u/Mangosteen)\ **Post date:** [August 19, 2013, 10:56pm UTC](https://boards.straightdope.com/t/tsunami-waves-vs-60-foot-cliff/666572/23 "2013-08-19T22:56:47Z")
> [@Gagundathar](#): > > Hey, **Mangosteen** , old buddy, old pal. We’ve always been real close, right? So, I was just wondering… if me and the missus were to uh… ‘drop by’ sometime for an extended visit… then that would be OK, right? You got lots of food, doncha? > > 😉 > > Seriously, your place sounds pretty amazing. I don’t suppose you have any pictures of the property or anything that you’d be comfortable sharing with us, do you? I’m fairly confident that I am not the only person here who is impressed with your setup there. Don’t have any recent photos, but here’s one just after we had the land cleared a couple of years ago. [http://img.photobucket.com/albums/v61/GarySiegel/Pepeekeo%20August%202011/Pepeekaoproperty30.jpg](http://smg.photobucket.com/user/GarySiegel/media/Pepeekeo%20August%202011/Pepeekaoproperty30.jpg.html) Shot of banana plants on the low side of the property next to stream. [http://img.photobucket.com/albums/v61/GarySiegel/Pepeekeo%20August%202011/DSC00341.jpg](http://smg.photobucket.com/user/GarySiegel/media/Pepeekeo%20August%202011/DSC00341.jpg.html) I’ll try to get some more photos when the house is completed. ---
**Author:** ![pudytat72](https://avatars.discourse-cdn.com/v4/letter/p/ce7236/32.png) [@pudytat72](https://boards.straightdope.com/u/pudytat72)\ **Post date:** [August 20, 2013, 4:24pm UTC](https://boards.straightdope.com/t/tsunami-waves-vs-60-foot-cliff/666572/24 "2013-08-20T16:24:23Z")
December 26, 2004: A catastrophic earthquake off the west coast of Sumatra, Indonesia (with a magnitude of between 9.1 and 9.3) generated tsunami waves of up to 100 feet that swept across the Indian Ocean, killing nearly 230,000 people in 14countries. 100 foot tsunami wave–\>60 foot cliff= problem ---
**Author:** ![Whiteknight](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whiteknight/32/4962_2.png) [@Whiteknight](https://boards.straightdope.com/u/Whiteknight)\ **Post date:** [August 20, 2013, 6:31pm UTC](https://boards.straightdope.com/t/tsunami-waves-vs-60-foot-cliff/666572/25 "2013-08-20T18:31:42Z")
> [@pudytat72](#): > > December 26, 2004: A catastrophic earthquake off the west coast of Sumatra, Indonesia (with a magnitude of between 9.1 and 9.3) generated tsunami waves of up to 100 feet that swept across the Indian Ocean, killing nearly 230,000 people in 14countries. > > 100 foot tsunami wave–\>60 foot cliff= problem The height of a wave at landfall is highly dependent on the coastal bathymetry. A tsunami wave traveling across the deep-water ocean might only be a few inches tall with a very long period. If you had a hypothetical, very long 60’ cliff that went straight down another 2000’ underwater the wave would arrive at just the same height it was crossing the ocean. It’s only when it gets into shallow water that a wave “feels the bottom” and builds in height. ---
**Author:** ![KneadToKnow](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kneadtoknow/32/3999_2.png) [@KneadToKnow](https://boards.straightdope.com/u/KneadToKnow)\ **Post date:** [August 20, 2013, 6:45pm UTC](https://boards.straightdope.com/t/tsunami-waves-vs-60-foot-cliff/666572/26 "2013-08-20T18:45:45Z")
_Tsharknami_, coming soon from SyFy. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [August 20, 2013, 6:52pm UTC](https://boards.straightdope.com/t/tsunami-waves-vs-60-foot-cliff/666572/27 "2013-08-20T18:52:10Z")
> [@Whiteknight](#): > > The height of a wave at landfall is highly dependent on the coastal bathymetry. A tsunami wave traveling across the deep-water ocean might only be a few inches tall with a very long period. If you had a hypothetical, very long 60’ cliff that went straight down another 2000’ underwater the wave would arrive at just the same height it was crossing the ocean. > > It’s only when it gets into shallow water that a wave “feels the bottom” and builds in height. [Like so.](http://en.wikipedia.org/wiki/File:Propagation_du_tsunami_en_profondeur_variable.gif) ---
**Author:** ![user\_hostile](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/user_hostile/32/474_2.png) [@user\_hostile](https://boards.straightdope.com/u/user_hostile)\ **Post date:** [August 20, 2013, 7:03pm UTC](https://boards.straightdope.com/t/tsunami-waves-vs-60-foot-cliff/666572/28 "2013-08-20T19:03:38Z")
> [@KneadToKnow](#): > > _Tsharknami_, coming soon from SyFy. In Japan, the channel is called _TsyFy_. ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [August 20, 2013, 7:35pm UTC](https://boards.straightdope.com/t/tsunami-waves-vs-60-foot-cliff/666572/29 "2013-08-20T19:35:52Z")
> [@pudytat72](#): > > December 26, 2004: A catastrophic earthquake off the west coast of Sumatra, Indonesia (with a magnitude of between 9.1 and 9.3) generated tsunami waves of up to 100 feet that swept across the Indian Ocean, killing nearly 230,000 people in 14countries. > > 100 foot tsunami wave–\>60 foot cliff= problem But by the time it reached Ceylon and south India, it was only 10 to 12 feet deep. Even in Aceh the flooding did not appear to reach those on the second floor of concrete buildings. By the Maldives(?) the rise was a few feet, which meant however it went through almost everything. What I was sking - don’t most of these quakes happen in the Pacific Rim,thouands of miles from Hawaii itself? Therefore the location would have to have extremely optimal contours to aggravate the tsunami height, and would still need to be an exceptionally huge quake. The news reports I google say the Japan tsunami was 7 feet when it hit Hawaii, 6 feet in some areas of California. > **[Archive blogs](https://www.latimes.com/archives/blogs/)** > > Los Angeles Times blogs that were published between 2006 and 2013. ---
**Author:** ![snowthx](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/snowthx/32/10660_2.png) [@snowthx](https://boards.straightdope.com/u/snowthx)\ **Post date:** [August 20, 2013, 9:00pm UTC](https://boards.straightdope.com/t/tsunami-waves-vs-60-foot-cliff/666572/30 "2013-08-20T21:00:11Z")
> [@md2000](#): > > What I was sking - don’t most of these quakes happen in the Pacific Rim,thouands of miles from Hawaii itself? Therefore the location would have to have extremely optimal contours to aggravate the tsunami height, and would still need to be an exceptionally huge quake. One such quake, the [1960 Valdivia earthquake](http://en.wikipedia.org/wiki/1960_Valdivia_earthquake) in Chile, sent waves across the Pacific, striking Hilo and killing 61 people. The waves were 35 ft in Japan and the Phillippines. ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [August 20, 2013, 10:00pm UTC](https://boards.straightdope.com/t/tsunami-waves-vs-60-foot-cliff/666572/31 "2013-08-20T22:00:41Z")
The waves at Hilo bay from the 1960 Chile quake were said to be 35 feet (vs. 17 feet elsewhere on the islands). I assume there’s some surf-and-focus effects there? I was wrong, apparently there are local quakes too… > **[Hawaiian Volcano Observatory](https://volcanoes.usgs.gov/observatories/hvo/about_earthquakes.html)** > > USGS: Volcano Hazards Program - Hawaiian Volcano Observatory USGS: Volcano Hazards Program Hawaiian Volcano Observatory Halape recorded 14m waves. And this: > [@](#): > > The most destructive waves ever to hit Hawai`i arrived on April Fool's Day. Triggered by a 7.1 level earthquake in the Aleutian Islands off Alaska, a tsunami broke over the north and east shores of the Islands, hitting the town of Hilo especially hard. Maximum wave run-ups of 55 feet were recorded in Pololu valley on Hawai`i island. [Previous page](https://boards.straightdope.com/t/tsunami-waves-vs-60-foot-cliff/666572.md?page=1)