Settle down in your bunker and get ready for yet another way for civilization as we know it to be wiped out! Tsunamis are most often the result of Past Volcanic Action that produces earthquakes. But when you start looking around for the really bad actors, Wiki the term “Sturzstrom” which are long run out earth slides.
These are not your average run of the mill earth slides, the tumble to the bottom of the hill and stop kind. No, these monster can “run” 20 times the height of the top of the “land” mass from which they spring or fall or whatever …
The interesting thing about the Struzstrom is that water is not needed for the flow. The mass, be it on dry land or down the side of the seamount underwater, flows on an incompressible layer of fines which acts as a lubricious bearing surface and just keeps the mass moving happily along.
While I can’t find a reference for it, I think the term “Sturzstrom” comes from the Swiss, the German part of the Swiss of course, who lost a village in the Alps, from just such a slide.
What is also interesting is when the USGS (Geological Survey) did a mapping study of the seafloor around the Hawaiian island chain they found that when they found a “sliding face” the run-out ratio was 20 to 1; i.e. a face who’s faced was a mile high, there was evidence of a 20 mile run out of previously fallen face, underwater.
These “slud” (blame that word on Dizzy Dean) faces are call debris aprons after they slide. And they are EVERYWHERE around the Hawaiian islands. Imagine how much energy was displaced into the water by those slides.
Finally, not only are we still in danger from the Hawaiian islands, the entire Eastern seaboard of the US is threatened by the Canary Islands, who are Past Volcanic Action face is aimed roughly at North Carolina. The possibility of a “megatsunami” or Minami is much greater than you think from such an event.
It has happened in the past and it will happen in the future. Imagine a 150 ft. wall hitting Myrtle Beach, just about the time for the Master’s, which is coming up in April. I think that Tiger’s jacket will be more than the funny shade of green. Wiki “megatsunami” for more info on this…