The nature article (of course) comes with the warnings that landslides will increase because of global warming. No evidence was provided, just a blanket statement.You can get a massive Tsunami from just a landslide.
Huge landslide triggered rare Greenland mega-tsunami - Nature
Scientists hope studying last month’s deadly event will improve modelling of rockslides that could become more frequent with climate change.www.nature.com
An offshore earthquake of the right type can generate a huge one.
2004 Indian Ocean earthquake and tsunami - Wikipedia
en.m.wikipedia.org