Unlike earthquake generated tsunamis, landslip ones get enormously high and can be even more destructive.
They’ve even happened in modern times and a couple of rare survivors of a half kilometre high wall of water describe the bizarre event here.
Pictured below, you can see the wreckage of what was half of the Hawaiian island of Molokai under the sea. That's a landslide.
RadioLIVE's Graeme Hill speaks with Alaskan geoscientist Bretwood Higman.
Bretwood discusses his warning that with current glacier retreat we should expect more of these shocking events.
Also, New Zealand geoscientist Dr Sam McColl of Massey University describes some truly bizarre landslip events in relatively recent history.
He also takes a look at how you can spot what happened on a map, and the prospects for such things to occur in the near future.
Listen to the full interview above.
Weekend Variety Wireless with Graeme Hill, 8pm - midnight Saturdays and Sundays, on RadioLIVE and streaming live to the Rova app on Android and iPhone.