Not every tsunami has an earthquake origin.
When I was listening to the news early this morning, 12-23-18, I heard the announcer mention tsunami and I immediately thought they were maybe doing a retrospective on the 2004 Boxing Day tsunami — but, it wasn't a retrospective, see Tsunami hits without warning in Indonesia.
There was no earthquake shaking as a warning, only the wave coming ashore that immediately began impacting people and property. There is this note from the story, “Actually, the tsunami was not really big, only 1 meter (3.3 feet),” said Prasetya, who has studied Krakatoa. “The problem is people always tend to build everything close to the shoreline.”
One death is too many, and the fact that this one did not kill over 200,000 people is little comfort to those who lost loved ones.