Today’s Earthquake Fact
Human beings can detect sounds in the frequency range 20-20,000 Hertz. If a P-wave refracts out of the rock surface into the air, and has a frequency in the audible range, it will be heard as a rumble. Most earthquake waves have a frequency of less than 20 Hz, so the waves themselves are usually not heard. Most of the rumbling noise heard during an earthquake are from buildings (and their contents) moving.
Today in Earthquake History
February 11, 1999
M 6, Afghanistan – Seventy people killed, 500 injured, at least 14,000 homeless and 7,000 houses destroyed in Lowgar and Vardak Provinces. Several people injured at… Read More