Extraction of <i>P</i> Wave From Ambient Seafloor Noise Observed by Distributed Acoustic Sensing
Takashi Tonegawa, Eiichiro Araki, Hiroyuki Matsumoto, Toshinori Kimura, Koichiro Obana, Gou Fujie, Ryuta Arai, Kazuya Shiraishi, Masaru Nakano, Yasuyuki Nakamura, Takashi Yokobiki, Shuichi Kodaira
Abstract
Abstract Seismic wave extractions have been performed using ambient noise records observed by distributed acoustic sensing (DAS) technology. Extractions of microseisms can be investigated at a local scale using such DAS records observed in the ocean. Here, we show P and Scholte wave extractions from ambient seafloor noise observed by DAS along a submarine cable deployed off Cape Muroto in the Nankai subduction zone, Japan. The P waves can be observed at a frequency band of 0.1–0.3 Hz and up to a distance of 8 km. The distance at which the P waves can be observed is controlled by the P incident angle and the DAS sensitivity to the observable apparent velocity. Effective extractions of P and Scholte waves, corresponding to large intensity of wave‐wave interaction at the sea surface, are performed, indicating that the waves are originated from pressure field at the sea surface.