Hi All. Found an interesting sight that allows you to hear an earthquake. It also has a little test you can take after you hear two quakes.

The site has good description of the “P” and “S” wave.

The mechanical properties of the rocks that seismic waves travel through quickly organize the waves into two types. Compressional waves, also known as primary or P waves, travel fastest, at speeds between 1.5 and 8 kilometers per second in the Earth's crust. Shear waves, also known as secondary or S waves, travel more slowly, usually at 60% to 70% of the speed of P waves. Seismologists measure the time between the arrival of the “P” and “S” wave then multiply this time by 8Kms to get a rough idea as to the distance from the seismometer that recorded the quake. It requires at least 3 or more seismometers to locate the quake.

The “P” wave is the only seismic wave that will travel through a liquid such as water. Being as how the “P” is a compressional wave and being as how water doesn’t compress very good the “P” wave will slow up quite a bit. If you don’t think this is true try doing a belly flop off a high diving board into a swimming pool and see who gets the worse of it. You or the water.

The dynamic, transient seismic waves from any substantial earthquake will propagate all around and entirely through the Earth. Given a sensitive enough detector, it is possible to record the seismic waves from even minor events occurring anywhere in the world at any other location on the globe.

There is a zone known as the shadow zone where quakes aren’t recorded. The zone is around 103° to 140° from the epicenter of the quake. They also have a fancy name for the location on the opposite side of the earth from the quake. It’s called the “antipodal” which is a fancy name meaning something on the exact opposite side.

Of course we also have the “L” and “R” waves. These are surface waves and they are the ones most of us feel. They are also the ones that do the most damage. Without them a quake wouldn’t be as bad as it could be despite its size. Its got to have those “L” and “R” waves which of course every self respecting quake has. Happy Turkey Day…Don the old gobbler in creepy town

• Listen To Earthquakes