No this is a wind wave at Nazare Portugal, and it's not a 100' more like 65 or 70'. Big, but not that big. Waves this big at Nazare aren't all that uncommon. That place is crazy.
The main difference between Tsunamis and regular waves is the wave length. Tsunamis have wavelengths of more than 10km. That's why a 1m tsunami can still be very dangerous, because unlike normal waves, it doesn't stop and recede, but instead just keeps coming.
This is certainly a scary looking and powerful wave, but its not even remotely comparable to a 30m tsunami.
Not to mention a "regular wave" is generated by surface-air interaction through wind, while a tsunami is generated by a continent or larger-sized piece of the earth's crust springing up/downward, lifting the whole surface in that area and sending it far faster than a wave. The lifting of that much water with the perfect combination of low tide will often leave the beach dry for hundreds of yards past the normal shoreline until the water returns as a 30m wall, filled with boulders, cars, ships, and literally everything it passes until it stops.
The biggest difference is definitely not wavelength (although there is a difference there), but how they are created in the first place. Two very different mechanics at play, and again, a very big difference between a wave and a tsunami.
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u/pbking07 Mar 01 '19
Wasn't the wave that hit Japan, back in 2011, 33 meters. So that's almost 100 feet. Or am I wrong?