S-net (Seafloor observation network for earthquakes and tsunamis along the Japan trench) is a real-time earthquake and tsunami monitoring network composed of 150 seafloor observatories deployed along the Japan Trench. We have investigated noise sources that affected seismic signals from S-net and make it difficult for the system to automatically detect earthquakes reliably. One of them is fin whale vocalization. Since the coverage area of the S-net overlaps with part of the habitat range of fin whales, numerous fin whale vocalizations have been recorded along with seismic data. Nakamura and Iwase (2020) developed a method to automatically identify and count fin whale vocalizations from continuous seismic records and applied it to S-net data from 150 seafloor observatories collected. Aggregating fin whale vocalizations by observation point revealed aspects of their annual behavior around the Japan trench. In this study, we analyzed seismic data from the S-net to visualize and examine the spatio-temporal distribution of fin whale vocalizations. Based on the constructed spatio-temporal distribution map, we will report on their recent year-round behavior around the Japan trench.
Mochizuki et al. (Wed,) studied this question.