A Preliminary Evaluation of Broadband Stations in Nigeria

Abstract

Preliminary evaluation of the performance of the Broadband Seismic Stations in Nigeria has been carried out. The aim is to test the recording capability, data quality for research and estimate the signal to noise ratios of the stations. The methodology involves the noise analysis for the Kaduna station located on basement complex in the northern part of Nigeria, and Nsukka station on the sedimentary basin in the South, using the Pascal Quick Look Extended (PQLX) package. In the first instance, data used in the research were continuously recorded during 2010 for 1-year period. Power spectral densities were computed from one-hour long data segments from both stations. Secondly, possible sources of noise to the stations as well as their signal to noise ratios (SNR) were estimated. Results from the first and second approaches were compared with the global noise models of Peterson’s. Thirdly, data from both stations were tested for research reliability using noise correlation and receiver functions techniques. The results showed high noise levels at both stations; low SNR at Nsukka and high SNR at Kaduna. Findings also showed that sources of noise to the stations are both natural and anthropogenic in nature. Results from noise correlations and receiver functions indicated that the correlations are antisymmetric indicating that the noise sources are non-uniform. The seasonal variations of the noise were also observed on the monthly correlations. The receiver functions computed from Nsukka station did not provide a sufficient number of receiver functions. There was no clear Moho conversion at Kaduna station and the results of H-K stack were poor. Findings from this study are expected to serve as references towards illuminating operational impediment associated with broadband stations in Nigeria and useful measures have been provided in this paper to improve data quality for healthy research.