[S-TT42] Applying optic fiber sensing to earth science

[STT42-P03] Lower crustal structure estimated from reflected S waves observed by an optic fiber sensing along Route 9 in Kyoto

*Masatoshi Miyazawa¹ (1.Disaster Prevention Research Institute, Kyoto University)

Keywords:DAS, seismic wavefield, crustal structure

Distributed acoustic sensing (DAS) technique is often used for measuring strain rate distributed along an optic fiber cable. The 2021 M2.8 earthquake and M3.2 earthquake in the crust were recorded by the DAS measurement using a 50 km cable along Route 9 in southern Kyoto, where the direct S-waves were followed by seismic waves reflected at lower crustal structures. The strain-rate wavefields of these earthquakes were simulated by implementing the lower crustal structures. The existence of a north-dipping reflector can explain the arrival time of reflected waves, while those amplitudes are faint if the planar reflector estimated by previous studies is assumed.