Analysis of seismic noise of broadband seismological stations installed along the Western Ghats

Abstract

The Western Ghats (WG) is one of the great escarpments that extend ~1500 km parallel to the west coast of India in the direction of NNW-SSE. We deployed a network of seven broadband seismological stations along the WG to decipher its evolution. In the present study, we investigate the characteristics of different kinds of noises at the stations by utilizing the power spectral density (PSD) measurements. Further, the results are compared with the global standard noise models to assess the data quality. The PSD results reveal that the short period (0.1–1 s) cultural noise is more prominent at stations AGMB, SDPR and MGLI when compared to the other stations, especially during day hours of Indian Standard Time (IST) zone since these sites were in the proximity of roads. The seasonal variations are observed especially in the microseismic period range and noise levels are more prominent in the months of July to August since the western part of India experiences peak monsoon during this period. These variations are observed especially at PCH and KNUR stations as their locations were near the coastline. Furthermore, the results indicate that the noise levels are more prominent in vertical components than that of horizontal components in the microseismic period range whereas it is reversed in the short and long period ranges. Later, the results indicate that the noise levels at all the localities of stations are within the global standard noise models, which suggests that our installation of broadband seismological stations has been successful at all seven locations and has good data quality.