VLF can apparently penetrate about 30m of sea water worldwide [1] when transmitted from one base station into the atmosphere. Not sure about ELF though. [1]: h

VLF can apparently penetrate about 30m of sea water worldwide [1] when transmitted from one base station into the atmosphere. Not sure about ELF though. [1]: https://en.wikipedia.org/wiki/VLF_transmitter_DHO38 https://en.wikipedia.org/wiki/VLF_transmitter_DHO38