COMPARISON OF GROUND MOTION MONITORING PERFORMANCE BY DAS TEST OBSERVATION USING MULTIPLE TYPES OF OPTICAL FIBERS AND INTERROGATORS [Translated Paper]

Abstract

In this study, five types of optical fiber cables were buried at a test site to carry out Distributed Acoustic Sensing (DAS) measurements. Three types of interrogators were independently tested with these buried cables, while multiple geophones were deployed at equal intervals for comparative analysis. Strain rate records, calculated by dividing the difference between adjacent geophones by the installation interval, confirmed that records of hammer-induced excitations were successfully obtained. Moreover, microtremor observation records were effective in estimating the phase velocity in the frequency band of approximately 2 Hz or higher. Seismic interferometry analysis of the DAS records and combination of DAS and microtremor records revealed that the dispersion curves are consistent with the Rayleigh wave phase velocity estimated by the microtremor survey.