Everyone talks about tsunamis caused by earthquakes and volcanic activity but none talk about tsunamis caused when large sections of islands suddenly breakoff and slide into the sea.
This activity produces an oceanic energy pulse equal to the volume of land that slides into the ocean.
Underwater mapping of the north coast of Hawaii shows several deep sea debris fields off the north coast. These debris fields are immediately off shore the near vertical cliffs of the north shore.
A few years ago there was a TV drama in Miami about a 30 foot tidal wave hitting caused by a big slide off the side of an island in the Azores. CSI Miami?