The spectrum of Earth strain from 10⁻⁸to 10²Hz

We have measured the power spectrum of the earth strain fluctuations over 10 decades in frequency from 10−8 to 102 Hz using data from three strain observatories. Although the strain meters were widely separated and of different design, they produced records whose power spectra are in close agreement with each other. We find that the composite power spectrum shows an approximate inverse square dependence on frequency over the entire band investigated.