[16p-M_278-1~6] Visualization of social infrastructure and disaster prevention using distributed acoustic sensors (DAS)

2:10 PM - 2:40 PM JST(5:10 AM - 5:40 AM UTC)

[16p-M_278-3] Quantitative comparison of active and passive surface wave data obtained from distributed acoustic sensing (DAS) and three-component velocity sensors

〇Koichi Hayashi¹, Hayato Nonaka², Hubbard Peter³, Yasuhiro Yokota⁴, Kensuke Date⁴, Kazuhiko Masumoto¹, Taka'aki Taira³, Kenichi Soga³ (1.DPRI Kyoto Univ., 2.KATRI Kajima Co., 3.UC Berkeley, 4.KATRIs Kajima Co.)

Keywords:

Surface wave method,Microtremors array measurements,S-wave velocity

We carried out comparative data acquisition of active and passive surface wave methods using three-component velocity meters (geophone) and distributed acoustic sensing (DAS). Several different fiber optic sensor cables were deployed at several different depths in a trench of 100 m length. Three component geophones were deployed on the ground surface along the trench with 2 m spacing. Active seismic data obtained from geophones was converted to strain time histories and quantitatively compared with DAS data. The strain time history obtained from DAS agreed very well with those obtained from the 2 Hz geophones. We compared dispersion curves of active and passive surface wave data obtained from geophones and DAS. Dispersion curves obtained from DAS are reasonably consistent with those obtained from the radial component of geophones. Processing results of passive measurements demonstrated that a low sensitivity cable used for telecommunication, and a cable on the ground surface loosely covered with soil, provided consistent dispersion curves with geophones. The results imply that DAS can be applied to various types of geotechnical monitoring.