Fig. 1. Diagram of deep sea DAS system

Fig. 2. Structure and data processing frame of mini-DAS module

Fig. 3. Structure diagram of pressure chamber for abyss

Fig. 4. Picture of sea trial. (a) Topographic map of location of sea trail; (b) photos of experimental site

Fig. 5. DAS records during base station entry. (a) Waterfall of 60 s long recording on May 21, 2022; (b) data of single channel vibration of 57th channel; (c) spectrogram of single channel vibration of 57th channel data; (d) data and spectrogram of single channel from 16 to 36 s of 57th channel

Fig. 6. DAS records during base station landing. (a) Time series data of landing process; (b) time-frequency spectrogram of DAS data during base station landing; (c) comparison of normalized energy spectrum of DAS record of base station landing and stress variation curve during submersible's landing process

Fig. 7. DAS records of base station loads throwing. (a) Time series data of base station loads throwing; (b) time-frequency spectrum of base station loads throwing; (c) statistics of normalized energy of original signal without frequency segmentation; (d) statistics of normalized energy with frequency segmentation; (e) zoom in figure of time-frequency spectrum

Fig. 8. DAS records during base station moving. (a) Time series data and spectrogram of base station stilling; (b) time series data and spectrogram of rudder propellers' gesture adjustment; (c) time series data and spectrogram of base station moving; (d) power spectrum of moving process