Just speculating. Wouldn’t an earthquake under shallow water produce less of a tsunami due to the fact it wouldn’t have to move as much water?
That is a logical thing to ask.
Being unfamiliar with the dynamics of earthquakes, tsunamis, etc., I have no idea but you ask a very good question.
Don’t know the answer but i’ve been up and down the caribbean and those islands are many and close. The potential for tsunami damage could be across many islands.
Just days ago I made a similar comment to my husband. I'll be watching the thread to see if someone has an answer (if I don't find it online first). Great minds & all...right?!
In my mind, the tsunami magnitude is a function of the relative displacement. At some location the elevation along both sides of the line change. The water displaced is a function the new elevation of the sea floor.
If the sea floor rises 10 feet, there will be more water displaced than if it only rises 5 feet.
If it occurs all on land, no displaced water, no tsunami.
If it was a thrust fault (one side moves vertical - pushing up) it would depend on how far it moved and how big an area of the ocean it moved under. Big up ward movement over a Big area Big wave!
Yes. A lot more is involved. I was just in the 6.5 earthquake( live close to Ferndale in California) and that one was from a fault in the ocean in fairly deep water. The movement however was horizontal plate movement and the major push of the tsunami even if vertical would have been out to sea more than toward shore.
No earthquake over 6.0 is humorous but it amazes me that folks still think waves can be generated into surfing waves by earthquake. The other myths were if 25 miles away then at the speed of sound a tsunami would still give folks time to vacate the area. Not so. The tsunami would be almost simultaneous Here's a little site I love:
regarding mythbusting tsunamis
Tsunamis propagate by up and down movement like a regular wave, not by horizontal pressure. Of course, the situation is not 100% clear cut because up and down movement causes changes in pressure as water builds up under the wave. Tsunamis travel fast because of their long wavelength. In shallow water, a wave's speed is given by c^2=gxd
where c = the speed of the wave (or phase velocity) in meters/sec, g = the gravitational acceleration (9.8066 meters/s2 ) and d = wave depth in meters. This means that as the depth doubles, the speed of the wave is quadrupled. In deep water, a wave's speed is described by linear wave theory, which assumes that transport of water is small enough to be ignored. The speed is given by c=gt/2pi or
t=0.641c
and
l=1.56t^2
where c = the speed of the wave (or phase velocity) in meters/second, g = the gravitational acceleration (9.8066 meters/second2), l = wavelength in meters, and t = time between crests (the wave period) in seconds. This equation means that at a constant depth, the speed is proportional to the wave period. A tsunami traveling at 450 miles per hour would have a wave period of 129 seconds and a wavelength of 16 miles. The waves will sharpen up somewhat and lose their sinusoidal shape as they approach the shore. The wavelength will also decrease because the waves are moving more slowly. However, the time between crests remains the same. The distance between wave peaks is always much longer than a regular wave.
Tsunami speed in ocean is not the speed of sound but: This myth is probably the reason some people think a tsunami is a compression wave. In fact, the speed of sound in salt water is about 1500 meters/second, or 3355 miles per hour. This is about 4.4 times faster than the speed of sound in air at sea level, which is about 742 miles per hour at 0 degrees C. (For the sake of comparison, the speed of sound in steel is 17 times faster than in air, or 13,332 miles per hour. At 30,000 feet, the speed of sound in air drops to 676 miles per hour.)
A tsunami traveling at 600 miles per hour is only going about 1/5 the speed of sound in water.