Seismic structure monitoring beneath the seafloor using ocean waves

Feasibility of monitoring seismic velocity structure using seismic noise observed in the seafloor is demonstrated through two different types of waves, infragravity wave in 0.005 - 0.02 Hz and microseisms in 0.1 - 3 Hz. The examples of seismic velocity measurement using these waves are shown by observation data obtained by seafloor observatories deployed in the Nankai Trough south of Japan seafloor.