Statistical study of anthropogenic seismic noise with IVK-7 computer system

An installation was set up at the Ashkhabad Central Seismic Station to record anthropogenic seismic noise, using a type IVK-7 computer system to accumulate and analyze the data. Noise at 15 and 30 Hz is processed; digital information obtained in real time is sent to the memory of the SN-3 computer included in the system. A strip chart recorder makes a continuous recording of the noise level at these two frequencies. The statistical characteristics, including distribution density, mean square values of random processes, autocorrelation function and spectral density were analyzed. The possibility is discussed of using the anthropogenic seismic noise from a large city to evaluate the stress state of nearby seismic focal zones. The most informative parameter is the frequency structure of high frequency seismic noise. Long term, continuous observations of the distribution of energy in the seismic noise spectrum may be informative for prediction purposes.