Factors influencing microtremor data collected using nested-triangular array configurations

Abstract

The availability of microtremor data is potentially affected by various external factors. By combining field data and artificial interference, this work aims to determine the correlation between these factors and the dispersion curve of fundamental-mode Rayleigh waves extracted from microtremors. The first step was to obtain real, high-quality microtremor records using a triangular ten-station array of 48-m radius. Secondly, a series of artificial or semi-artificial interferences of varying type, duration, amplitude, etc., were generated and combined with the real records to imitate actual interferences. Thirdly, all the dispersion curves of the fundamental-mode Rayleigh waves of these modified microtremor records were estimated using the extended spatial autocorrelation method (ESAC). Finally, by comparing the experimental dispersion curves with the original curve, in terms of overlap ratio, we obtained useful conclusions that can be directly applied to microtremor data collection and analysis.