themilum:

You may be smart, but on this one I suspect you are incorrect. Waves of mechanical energy move more quickly through denser material as a general rule.

Sound travels faster underwater than it does through the air, by a considerable margin:

"Therefore, the speed of sound is about four times faster in water than in air." http://hypertextbook.com/facts/2000/NickyDu.shtml

From the same source "The speed of sound in a medium can be determined by the equation...

v = (B/ñ)1/2 (this 1/2 is in the original text an exponent, meaning that the velocity of sound is the square root of the ratio B/ñ)

Where...

v is the speed of sound,
B is the bulk modulus of elasticity, and
ñ (rho) is the density.

The bulk modulus of elasticity, also known as the compressibility, is the relationship between pressure and volume. It is a measure of how much an increase in pressure would decrease the volume."

It's my understanding that the nature of a seismic wave is sound, that is a longitudinal mechanical wave of energy. The Earth rings "like a bell" when there is seismic activity.

Whether the waves of sound move more slowly through the iron core of the earth is basically a matter of the elasticity or lack thereof of the iron core. Take as an example a ball made of rubber. If you hit it (make a sound) on one side, the elasticity is such that it deadens the sound (which is the same thing as saying that the speed of sound in the medium rubber is slowed to zero.) Not the same when you strike the side of an iron ball. My guess is that the bulk modulus of the iron core of the earth is really high, because it is already compressed greatly. Any sound hitting it is going to go right through (and very quickly) because the iron cannot further compress.


TEd


TEd