Studies of Long-Period Seismic Noise Generated by Atmospheric Pressure Changes

Abstract : Potential contribution of atmospheric pressure sources other than the wind to the seismic noise spectrum in the 20-100 second period range was studied. Results indicate that during calm intervals in the winter months, pressure related earth motion makes a substantial contribution to the observed earth noise spectrum. This contribution becomes detectable at periods on the order of 25 seconds and becomes the principal source of ambient earth motion at periods greater than 50-60 seconds. The evidence to date strongly suggests that the pressure related earth motion is derived principally from naturally occurring atmospheric infrasonic waves.