Tuesday, May 05, 2009

Hawaii: More volcanoes and giant tsunamis loom ("How the Earth Was Made": History Channel)

On Tuesday, May 5, 2009 The History Channel presented another ominous entry in its “How the Earth Was Made” series with emphasis on volcanos. This time, the treat was “Hawaii”. Here is the latest link.

The Big Island may lie over a hot spot that goes all the way to the center of the Earth, Jules Verne style (even more so than Yellowstone). The show covered the Great Crack, or Hilina Slump. A coastal underwater volcano called Loihi will become the next island and one day reside over the tube, exposed to “mantle plumes” from deep within the earth.

The high cliffs (Molokai) rising to 1700 feet above the water are the tallest seaside cliffs in the world. All of this gives evidence of the likelihood of landslides some day, that could send one of the largest tsunamis possible, over 1000 feet high, past Oahu to the West Coast of the US and possibly Japan, depending on circumstances. The risk could be comparable to or perhaps greater than that posed by the Canary Island volcanoes for the Atlantic as recently discussed here. The cliffs show that such a tsunami has occurred in the past.

The Hawaiian islands are part of a “straight line” underwater ridge, caused by meeting plates, extending for 3000 miles to the west. Portions of the islands have appeared and disappeared suddenly. Wikipedia shows the extended archipelago with a diagram and NASA photograph.

I visited Hawaii in 1980, and rented cars on the Big Island (the rental contract did not allow us to drive up Mauna Loa, which required a 4-wheel drive), and Maui. I did drive up Haleakala crater, at 10000 feet, where in August the temperature was in the 50s in mid morning. On the same trip, with a triangle fare on the now defunct Braniff, I also visited Anchorage, and flew of Mount St. Helens, still steaming, on the way to San Francisco afterward. I also remember that in Hilo there occurred one of the only two bar fights I have ever witnessed (the other was in Soho London in 1982).

I visited Kilauea on the 1980 trip. It was not erupting, but was steaming in many areas, and one could walk in limited areas near visible hot spots.

Attribution link for Kilauea commons picture, here.

Attribution link for Maui Haleakala crater, pretty much what I saw, here.

(For a write up on "Volcanic Winter", the Mega Disater episode that followed, see this blog on June 10, 2008).

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