Borehole Fiber-Optic Cables for Monitoring Ocean Dynamics: Case Study from Australia

The interaction between ocean waves and the seafloor produces microseisms which propagate through the solid Earth and may be used to monitor distant storms, local wave climate, seafloor sediments, and bottom biomes. We show that onshore boreholes equipped with fiber-optic (FO) cables enable advanced analysis of microseisms, and thus provide a promising tool for oceanographic remote-sensing applications. Contrary to traditional surface seismometers, borehole FO cables allow distributed acoustic sensing (DAS), whereby seismic amplitude may be sampled continuously with depth, providing greater information and signal-processing advantages. DAS systems may easily be installed in boreholes, and given the sheer number of boreholes in near coastal areas around Australia, may provide an efficient, cost-effective, and real-time network for monitoring and studying ocean dynamics, coastal wave impacts, and climate change.