A plan of continuous monitoring of seismic signature at the top of the subducting Philippine Sea Plate using the ACROSS active monitoring method

Kasahara, Junzo; Tsuruga, Kayoko; Hasada, Yoko; Yamaoka, Koshun; Kunitomo, Takahiro; Watanabe, Toshiki; Fujii, Naoyuki

Recently, a very strong reflected PP phase from the subducting plate boundary was found beneath the aseismic forearc slope of the Japan Trench. Similar strong PP reflection phase was observed near the plate boundary of the subducting Philippine Sea Plate and the Eurasian Plate, in the western part of Shizuoka Prefecture. These strong PP reflections are interpreted as reflections from the non-asperity region along the plate boundary caused by the presence of low-Vp material. Using continuous transmission of seismic waves from the ACROSS source located and /or the new ACROSS source under planning and the high sensitivity seismometers along the NS traverse line, we can delineate the temporal variation of seismic wave properties of the anomalously reflected PP phase along the boundary of subducting Philippine Sea Plate.