bobhenstra wrote:So, where is the strength in EQ shock waves of less than one hertz? How does a frequency of less than one hertz "signal?" earthquakes in distance areas as the map above supposedly shows? It would seem to me that if the supposition is true that frequencies of a percentage of less than one would have to have a big increase in power to effect areas of the distance shown on the map, and I don't see how that is possible!
I guess that I'm have trouble understanding how an EQ frequency of .50 hertz, or a sub hertz frequency, is more powerful than frequencies at 1 or above (one) hertz! Radio frequencies are not applicable here. As I understand it earthquake S and P waves are shock waves. On a seismograph when S and P waves flat line, there are no more waves, so how do weakened "sub hertz" waves trigger earthquakes at the distances claimed in the map above?
The frequency is different from the amplitude of the wave. The amplitude is the height or magnitude of the wave. Both frequency and amplitude have an effect on the "power" or energy in the wave, and a higher frequency (changing or moving faster) means more energy.
Earthquakes are usually so slow that the frequency doesn't make a big different in the power, so they mostly measure amplitude.
I think what it was saying above is not that lower frequency quakes have more power, but that they carry further through the earth, ie the waves are not dampened as much by stable material as high frequency waves would be.