(March 17, 2011 at 4:29 pm)Chuck Wrote: Did the quake cause any downward displacement and permanent drowning of the coastal region behind the headwall like there was on the coast of Oregon as a result of the 1700 Cascadia quake? Since the Cascadia trench appears to be substantially closer to coast then the one off Japan, a rupture on the Cascadia trench will give much shorter warning time between quake and Tsunami. Is there any study on what sort of Tsunami would result from shelf and coastal topography off Oregon?
It is probably too early to tell. Likely, all that will come out once the quake is studied in detail and the results published. Kerry Sieh, of Caltech, published a paper in January of 2004 that warned of an impending earthquake along the Sumatran trench in the vicinity where the Boxer day earthquake occurred. His evidence included pre-quake uplift along the coast resulting in exposure of coral reefs and the islands offshore that was a result of flexure/bulging of the plate boundary prior to rupture. I don't know if any of that was seen before this Japanese event, but since that megathrust zone is further offshore, it is unlikely that such uplift was seen onshore. If it had, it would likely have raised alarm bells in Japanese academia. I guess we'll have to wait until some papers are published before we will know for sure.
As for the Cascadia subduction zone, I've known about it for a long time (ever since Brian Atwood first published his paper), but I am no expert on that area. I would do a search for some of his papers and see what he thinks. He's with the U.S.G.S. I do know that there have been tsunami studies of the Cascadia subduction zone, though I couldn't quote from any of them since I've not read them. What I do know is that any megathrust temblor of similar magnitude in the Cascadia zone would be devastating to the Pacific Northwest, and possibly further afield.
It is an interesting question whether such bulging would occur in the Cascadia, since the fault is of shallow dip. But having such a shallow dip angle also means that a much broader region could be affected by the quake itself. This does not bode well for Seattle and vicinity.
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"I think that in the discussion of natural problems we ought to begin not with the scriptures, but with experiments, demonstrations, and observations".
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"In short, Meyer has shown that his first disastrous book was not a fluke: he is capable of going into any field in which he has no training or research experience and botching it just as badly as he did molecular biology. As I've written before, if you are a complete amateur and don't understand a subject, don't demonstrate the Dunning-Kruger effect by writing a book about it and proving your ignorance to everyone else! "
- Dr. Donald Prothero
-- Samuel "Mark Twain" Clemens
"I think that in the discussion of natural problems we ought to begin not with the scriptures, but with experiments, demonstrations, and observations".
- Galileo Galilei (1564-1642)
"In short, Meyer has shown that his first disastrous book was not a fluke: he is capable of going into any field in which he has no training or research experience and botching it just as badly as he did molecular biology. As I've written before, if you are a complete amateur and don't understand a subject, don't demonstrate the Dunning-Kruger effect by writing a book about it and proving your ignorance to everyone else! "
- Dr. Donald Prothero
