Measurements of shipping, fin whales, earthquakes and other soundscape components at the Lofoten-Vesterålen Observatory, Norway (2018-2019)

Underwater soundscapes are complex as they are the combination of several components with overlapping acoustic frequencies and different timescales, from individual durations to seasonality and long-term trends. Sounds below 100 Hz are of particular interest to compare human impacts (e.g. shipping and geophysical exploration) with natural processes (e.g. earthquakes and weather) and animal vocalisations (e.g. whales), but understanding is often limited to specific signals on their own, not their combination . We have processed over two years (2018 and 2019) of measurements from the Lofoten-Vesterålen cabled ocean observatory, located 15 km offshore northern Norway, at a depth of 255 m. Earlier analyses (Garibbo et al., 2020, Garibbo et al., 2021) identified the different contributions of weather, shipping and earthquakes in data collected in 2018, using deep learning to automatically detect common 20 Hz fin whale calls. The results of the deep learning approach are compared to a new, improved shipping detector, based on traditional spectral analyses, showing the complementarity of each approach. By extending these analyses using data from 2019, we can quantify the standard soundscape components based on origins, frequency ranges and seasonality, and assess their variability over time. Some sources (e.g. earthquakes) can be thousands of kilometres from the observatory, showing low-frequency soundscapes include information over large regions of the ocean. This paper summarises the main findings of this work including a description of the analysis methods used and the resulting components of the soundscapes. These extensive results provide a useful baseline for further studies of other low-frequency environments around the world.