California quake model looks for ‘mega-quake’ along Cascadia

January 11, 2013PORTLAND, Or. – New research is giving us some insight into when a major earthquake could strike the Northwest. The research was done in part by Stanford geophysics Professor Paul Segall. He has been tracking a series of very small tremors that rumble deep within the earth. The slow tremors happen roughly every summer along the Cascadia Subduction Zone, an undersea fault about 70 miles off the Oregon Coast. Over the last decade, data shows the tremors have been getting progressively bigger. Last summer, the Pacific Northwest experienced a notably large one. Experts believe those tremors are adding stress to the offshore fault. Using this data, Segall built a computer model which suggests it will be one of those tiny quakes that triggers a major magnitude 9 earthquake. “What we do see is that ultimately one of these tends to develop into a fast and potentially, damaging earthquake,” said Segall. Segall said that scientists don’t yet know how big those tremors need to get before they explode into a mega-thrust quake. And that means a major earthquake in the Pacific Northwest could still be hundreds of years away. But, he added, those tiny tremors are a good reminder that we always need to be prepared. Scientists discover the largest-known spiral galaxy. –King 5 
San Andreas stress rupture could shake entire state: For the first time, scientists and emergency planners are examining whether a super quake could affect both Northern and Southern California, rendering the entire state helpless in the aftermath of the “Big One.” Seismologists have warned Southern California that a major quake on the lower San Andreas Fault, the so-called Big One is inevitable. But that the population centers of both Southern and Northern California could be affected simultaneously by one quake on the San Andreas Fault has only recently been recognized as a possibility. The study by Professor Nadia Lapusta at the California Institute of Technology (Caltech) and Japanese collaborator Hiroyuki Noda focused on explaining the behavior of two devastating quakes in Asia: the 1999 magnitude 7.6 temblor in Taiwan, and the 2011 magnitude 9.0 quake off the eastern coast of Japan. In both cases, the quake spread across so-called “creeping“ fault segments long thought to be incapable of transmitting quakes, according to Caltech Staff Seismologist Kate Hutton, a Lapusta colleague. “The general idea until this paper was that they would stop a quake,” Hutton said. It was believed the slow, creeping movement prevents stress from building up  and keeps  such a segment stable, Hutton added. Lapusta and Noda developed a computer model to explain how under certain conditions “a rupture could just kind of barge right through,” Hutton said. “Now the question is how this would apply to California.” Such a creeping zone has been identified in a stretch of the San Andreas Fault in central California, just north of seismically active Parkfield. The Great San Francisco quake of 1906 occurred on the San Andreas north of the creeping zone. The 1857 Fort Tejon quake occurred to the south. No known quake has ever spanned across that creeping zone. Whether the model developed by Lapusta and Noda could apply there would depend on local geological variables not yet completely understood, Hutton said. –NBC LA
                                                 Countdown to a catastrophic mega-quake in the U.S.
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13 Responses to California quake model looks for ‘mega-quake’ along Cascadia

  1. thanks…i was hoping you would cover the VERY telling EQ patterns that are happening right on the san andreas right now and for days…starts smaller in so cal and gets larger and moves up towards eureka. it’s been cycling like that for days, as i said. they are getting slightly bigger as well.

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  2. Therese Denbeck says:

    I’m curious about a dream that I had once where a hand came out of oval shaped clearing in the clouds and picked what looked like a stick that you see used as a stake for tomatoes. The only area that is resonat to the shape and colors which seem to be what I believe is considered the locked area (ref. USGS California map there is an area which is yellow in the same shape as in my dream adjacent Taft and below Parkfield) close enough for me I guess.

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  3. Marshallrn says:

    The video points out that this event would be bad but the US can rebuild itself. Yet they don’t say what the individual can do to help avoid making the situation worse, or what would happen if there were more events going on nation wide. Compounding events can tax nations resources and make it much worse for all.

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  4. Irene C says:

    This report doesn’t surprise me. As they say, It’s not a matter of it, but when. On another note, the tremors travelling from west to east is continuing. There was a 2.7 in Illinois. Not much on it’s own, but the pattern has drawn my attention.

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  5. WilliamHill says:

    This is all well and good and I do believe the BIG ONE is coming, but who is watching all the quakes in east TN, east KY, and West Virginia? They are giving California a run of the most daily quakes.Your thoughts?

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    • Irene C says:

      William, I’m glad someone else is noticing this. the quakes are moving west to east. It’s becoming unnerving, like something is coming our way. Everyone looks towards the West coast, as they should, but so many ignore the Midwest and the East coast.

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    • Louise Page says:

      Sometimes (and this only my amateur observation/feeling) I think that when the focus of attention is directed to one area predominantly, another can come up as the surprise event in a different area. The east needs to be observed quietly, along with the happenings in the west.
      There seems to be a ‘line’ (of sorts) which one can mentally draw from the east coast, through the lower states of the U.S., through to the west coast (and up, obviously, to the border with Canada – even up into the Gulf of Alaska).
      I tend to feel that there is a geological/faults ‘relationship’ associating all of these states (generally speaking).
      The Earth is definitely ‘talking’ in many areas on the planet, but I feel it is worth observing and keeping in mind the activity in the eastern states.
      Just a thought……

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  6. Irene C says:

    Just because I thought this was important: ACTIVE SUNSPOT: One of the biggest sunspots of the current solar cycle is now turning toward Earth. Named AR1654, the active region is crackling with medium-sized (M-class) flares and could be poised to break the recent spell of calm space weather around our planet. spaceweather.com

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  7. sarahandcoryb@yahoo.com says:

    The earthquake in Illinois scares me. When they start to pop up in new states and close to the New Madrid faultline it’s scary because its so new. Maybe no place will be safe if this continues. Lets hope not. Love your site. Been a follower for a few years now. All the information is somewhat calming. Better to know then be blind. Thank you Alvin.

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  8. Philip Janes says:

    I have been analyzing the timeline of Cascadia quakes of magnitude 8+ and 9+ over the last 6000 years.

    http://www.oregongeology.org/sub/quarpub/CascadiaWinter2010.pdf

    I have made graphs of the average time remaining to the next one (y years), given that x number of years have passed since the previous one. What I am finding is that, if you only look at 9+ quakes, the time since the last one doesn’t seem to matter much. But if you look at time since the last 8+ quake, the average time remaining to the next 8+ and the next 9+ can be quite short.

    It has been 313 years since the last 8+, which was also a 9+. My graphs suggest roughly a 50% chance of a 9+ in the next 50 years. I’m sure professional geologists are capable of doing a better analysis than I can, but I’m not sure they are sharing their most worrisome forecasts with the public.

    I live one mile from the Washington coast, near Westport, so I have taken some precautions. My back yard is about 40 feet above mean sea level, the same height as the official gathering point a block away. I keep emergency supplies on top of the hill, and I have an extension ladder already tied to a tall tree as a last resort. I expect to be on my own out here in the boonies for up to a month; rescuers will be overwhelmed in the cities, where most of the casualties will be located. My tree may not be high enough to save me, but there will be no possibility of reaching any better refuge when the time comes. Roads and bridges will be impassible, and there are no public vertical evacuation shelters along this part of the coast. No structure on this part of the coast can withstand a large tsunami. There is one small area near the coast which is 60 feet above sea level, and that may not be high enough.

    Much of the commercial and industrial areas, here, already flood when large waves coincide with a high tide. After the great quake, the land will be about 6 feet lower. Having lost perhaps 95% of the tax base, cities like Westport will be abandoned for many decades.

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  9. NiNzrez says:

    just giving a heads up that, at the end of the 1st part of the cali quake model write up, you added the title for the post below it, at the end of the section
    “But, he added, those tiny tremors are a good reminder that we always need to be prepared. (this part–> )Scientists discover the largest-known spiral galaxy. –King 5

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  10. J Martin says:

    Philip Janes said It has been 313 years since the last 8+, which was also a 9+

    That was during the Maunder Minimum, 1645 to 1715. We are now entering a new minimum, the Landscheidt Minimum, which was predicted by Theodor Landscheidt back in the 1980s.

    It is known that quakes and volcanic activity increase during periods of solar minima. If Landscheidt is correct when he suggested that this minimum could turn out to be as deep or deeper than the Maunder Minimum then the USA may see some quake action, we are already seeing a ramping up of volcanic activity elsewhere in the World.

    Just waiting for Katla.

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