SEGJ Technical Conference

Seismic Interferometry Analysis on microtremors records observed by a linear array with broadband seismometers in Fukushima Prefecture Part 2

Abstract The purpose of this study is to conducted a broadband linear array observation with 10 sites in Fukushima Prefecture in order to estimate deep crustal structures down to the plate boundary based on the seismic interferometry analysis. Cross-correlation functions calculated from 8 months observed vertical records of microtrmors showed wave-propagation characteristics. SN ratios and group velocities were estimated as a function of periods by applying multiple filter analysis to stacked cross-correlation functions. From a comparison between group velocities in the positive direction and those in the negative direction, the threshold values of the SN ratio must be 10. From a comparison between the observed average group velocities and calculated ones by Nishida's Vs model, observed group velocities were smaller than calculated ones.