Friday, February 8, 2008

We have a Winner!

That didn't take long, Ron

Many of the details of Mt. Shasta's complex history are summarized nicely by Bill Hirt at The small hills and ponds are part of the hummocky topography produced by a giant debris avalanche that broke loose from the north flank of Mt. Shasta Version 1.0 or 2.0 (Note that the modern Mt. Shasta is something like version 5.0; Sargents Ridge, Misery Hill, and Shastina are all earlier volcanoes that preceded the young summit called Hotlum Cone). The topography, seen from the air in Picture of the Day - The Airliner Chronicles Part 11, was an enigma to geologists until 1980 when the debris avalanche thundered off of Mt. St. Helens, producing a similar topography in the Toutle River Valley. The Shasta avalanche was much larger, traveling some 55 kilometers, making it one of the biggest ever documented.

Here is one more photo showing Shasta (the two summits are Shastina and Hotlum Cone), and a portion of the debris field along Interstate 5. Good job, Ron!

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