Abstract

Preliminary noise analysis has been carried out on the Z-components of the Nigerian National Network of Seismographic Stations (NNNSS) using data collected from the five operational stations (Toro, Kaduna, Nsukka, Awka and Ife) in 2012. The results of the analysis from noise spectra using SEISAN software clearly showed that the noise levels at the respective stations are high and the average noise levels are above the high noise model of Peterson curves. The possible sources of noise are cultural, actual earth vibrations and instrumentation. The study is intended to quantify the amount of noise present in the existing NNNSS and compare with Peterson noise curves, and understand the noise characteristics in order to adopt better practices in the day-to-day seismic stations’ operations in Nigeria.

Key words: National network of seismographic stations (NNNSS), noise, spectral analysis, signal to noise ratio.