Being a nerd, I tend to pore over Wiki in all places. The other day I looked up Moloka’i (the island to the right of the sunsets here in West Maui) after reading about this event in the copy of Maui Revealed someone left here:

The northern half suffered a catastrophic collapse about 1.5 million years ago and now lies as a debris field scattered northward across the Pacific Ocean bottom,[5] while what remains on the island are the highest sea cliffs in the world.

Tonight at Leilani’s (the downstairs restaurant; underwhelming food, but cheap, then followed by dessert at the Haagen Dazs I was going on about a couple years ago) I looked up the Hawaiian Islands so I could see where exactly they all are in relation to one another (I tend to think of Lanai and Molokai being stuck off to the Northern side of the archipelago, but if you follow the line Molokai draws it runs straight into Oahu) and one link led to another and I found the article on the Hilina Slump:

The Hilina Slump is a 4,760 cubic mile (20,000 kilometre¬≥) chunk of the big island of Hawaii on the south flank of the Kilauea volcano. Between 1990 and 1993, Global Positioning System measurements showed a southward displacement of the south flank of Kilauea up to approximately 10 centimeters per year… If the entire Hilina Slump did slide into the ocean at once, it could cause an earthquake in excess of a 9 in magnitude and a megatsunami. Previous megatsunamis in Hawaii 110,000 years ago caused by similar geological phenomena created waves 1,600 feet (487 m) tall. Were such a megatsunami to occur again, it would threaten the entire Pacific Rim.

Oh, good!