Mechanism is via conversion of neutrinos into charged particles which are then detected via Cherenkov radiation which is produced when a charged particle moves with speeds larger then the speed of light in the medium. (That is only possible because it is less than the speed of light in vacuum which cannot be exceeded.)
https://en.wikipedia.org/wiki/IceCube_Neutrino_Observatory
Mechanism is via conversion of neutrinos into charged particles which are then detected via Cherenkov radiation which is produced when a charged particle moves with speeds larger then the speed of light in the medium. (That is only possible because it is less than the speed of light in vacuum which cannot be exceeded.)
This was also discussed recently if you are interested: https://news.ycombinator.com/item?id=49655286
https://en.wikipedia.org/wiki/Cherenkov_radiation