I have taught in my High School Physics classes that the speed of a
mechanical wave is determined by the medium. This, presumably, is why
loud sounds do not overtake soft sounds and makes our communication with
each other manageable when speaking. Pebbles or rocks dropped into a
pond create circular wave fronts but I have never seen one of the
circles pass up another. I imagine it could if one wave interacts with
the bottom of the pond (larger amplitude) differently from another.
But, if the depth is far greater than the amplitude of the wave, should
they all travel at the same speed?
If the medium changes, as in higher air pressure, then the speed of
sound waves changes.
And yet the subject of tsunami waves causes me some confusion. I
realize that the speed of a water wave depends on the depth of the water
as different depths represent different media. Surface ocean waves,
over deep sections of the ocean, do not interact with the bottom of the
ocean and so, ignoring wind and other factors that might influence
speed, their speed is determined by the medium somehow. Now, suppose
that the ocean were uniformly "very deep", perhaps 1000's of km, would
this mean that even a large tsunami wave would travel at the same speed
as a normal surface wave?
A secondary question concerns the speed of a wave in its dependence on
wavelength. Some references indicate a longer wavelength means a
greater speed. What is the mechanism that explains this? Also, suppose
a single pulse is created, then there is no wavelength so what does the
speed depend on now. Is it possible to produce a single pulse?
If anyone can illuminate my probable misconceptions, I welcome the
correct explanations.