May 24, 2010
Earthquake Risk Calculated For US Northwest

Move over California. Oregon, Washington state, and British Columbia might have a far more devastating earthquake.

CORVALLIS, Ore. – The major earthquakes that devastated Chile earlier this year and which triggered the catastrophic Indonesian tsunami of 2004 are more than just a distinct possibility to strike the Pacific Northwest coast of the United States, scientists say.

There is more than a one-in-three chance that it will happen within the next 50 years.

New analyses by Oregon State University marine geologist Chris Goldfinger and his colleagues have provided fresh insights into the Northwest’s turbulent seismic history – where magnitude 8.2 (or higher) earthquakes have occurred 41 times during the past 10,000 years. Those earthquakes were thought to generally occur every 500 years, but as scientists delve more deeply into the offshore sediments and other evidence, they have discovered a great deal more complexity to the Cascadia Subduction Zone.

Lots of disasters are just waiting to happen. Earthquakes, large volcanic eruptions, asteroid strikes, and even another Carrington Event could cause massive disruptions. Earthquakes are the least of the 4 listed disasters in terms of potential for lives lost and disruption.

Watch out for a mega-quake.

Based on historical averages, Goldfinger says the southern end of the fault – from about Newport, Ore., to northern California – has a 37 percent chance of producing a major earthquake in the next 50 years. The odds that a mega-quake will hit the northern segment, from Seaside, Ore., to Vancouver Island in British Columbia, are more like 10 to 15 percent.

A magnitude 9 earthquake would tear highways to pieces. Imagine trying to bring in help afterward. Rail lines and highways would be impassable. My guess is the rail lines could be restored to working order much faster.

The OSU professor is convinced that the Pacific Northwest is at risk for an earthquake that could meet – or exceed – the power of seismic events that took place in Chile, as well as Haiti. If a magnitude-9 earthquake does strike Cascadia, he says, the ground could shake for several minutes. Highways could be torn to pieces, bridges may collapse, and buildings would be damaged or even crumble. If the epicenter is just offshore, coastal residents could have as little as 15 minutes of warning before a tsunami could strike.

Anyone who lives in the northwest made any special preparations for an earthquake? Ready to survive for weeks without electric power or city water?

Share |      Randall Parker, 2010 May 24 10:34 PM  Dangers Natural Geological

Black Death said at May 25, 2010 7:35 AM:

Mount Rainier could erupt at any time. From Wiki:

The most recent recorded volcanic eruption was between 1820 and 1854, but many eyewitnesses reported eruptive activity in 1858, 1870, 1879, 1882 and 1894 as well.[18] Although Rainier is an active volcano, as of 2010 there is no evidence of an imminent eruption.[19] However, an eruption could be devastating for all areas surrounding the volcano.[20] Mt. Rainer is currently listed as a Decade Volcano, or one of the 16 volcanoes with the greatest likelihood of causing great loss of life and property if eruptive activity resumes.[21] Despite the risk, there are currently no zoning restrictions in King County due to volcanic hazard.[22] If Mt. Rainier were to erupt as powerfully as Mount St. Helens did in its infamous May 18, 1980 eruption; the effect would be cumulatively greater, because of the far more massive amounts of glacial ice locked on the volcano compared to Mount St. Helens[17] and the more heavily populated areas surrounding Rainier.[23] Lahars from Rainier pose the most risk to life and property,[24] as many communities lie atop older lahar deposits. Not only is there much ice atop the volcano, the volcano is also slowly being weakened by hydrothermal activity. According to Geoff Clayton, a geologist with RH2, a repeat of the Osceola mudflow would destroy Enumclaw, Orting, Kent, Auburn, and most or all of Renton.[16] Such a mudflow might also reach down the Duwamish estuary and destroy parts of downtown Seattle, and cause tsunamis in Puget Sound and Lake Washington. According to USGS, about 150,000 people live on top of old lahar deposits of Rainier.[25] Rainier is also capable of producing pyroclastic flows as well as lava.[26]

Bill Thomas said at May 25, 2010 6:39 PM:
Anyone who lives in the northwest made any special preparations for an earthquake? Ready to survive for weeks without electric power or city water?
Yes. I have a solar setup that can handle recharging all my small electronics and batteries, as well as a few LED light bulbs, a mini-refrigerator. I also have a Berkey water filter that will purify any sort of fresh water, as well as a rainfall harvesting system. and several hundred gallons of water already stored. I also have food and other necessities - including things like toilet paper and a chemical toilet - to last considerably more than a few weeks or even a few months.

I live in San Francisco. You have to be aware of quakes if you live here, or so one might think, but astonishingly, I'd guess less than a handful of the locals are prepared to last beyond what is in their fridge and cupboards, and in their faucets and toilet tanks. If they even think of that.

biobob said at May 26, 2010 11:06 AM:

I am always amazed at the apparent certainty that these "scientists" employ for their WAGs.

Why not 37.6012 % or perhaps 34% because he is a pessimist ? LOL

rosignol said at May 26, 2010 11:16 AM:

Anyone who lives in the northwest made any special preparations for an earthquake? Ready to survive for weeks without electric power or city water?


I have never understood how the people down in Florida or the gulf coast can be 'caught unprepared' when a hurricane hits. They knew it was out there, even if they didn't know exactly where it would go.

On the west coast, someone who could reliably predict the location and magnitude of a quake 24 hours before it hit would be a multimillionaire.

Stephen said at May 26, 2010 11:27 AM:

The comparative rarity of rational individual event-preparation will mean you may be a "have." Does rational event-preparation, then, include preparations to deal with the unprepared "have-nots"? Should there be neighborhood planning?

Beryl said at May 26, 2010 12:03 PM:

Everybody needs to prepare for the dangers specific to where they live. Tornadoes in the Plains, hurricanes in the Gulf States, and seismic activity in the Midwest and West. I lived in Los Angeles during the 1972 quake and Portland, OR during the Mt. St. Helens eruption and saw how even areas outside the catastrophe area are disrupted.

I now live on an island in north Puget Sound at 32 meters elevation (no real tsunami risk.) I have about a month's worth of food and water in store, and agreements with several neighbors about how to deal with these kinds of emergencies. A few minor emergencies (heavy snowfall, water main problems, power outages) have provided us with "dry runs" of our emergency cooperation. I'm sure that on Der Tag, we will have neighbors who didn't want to participate in our preperations wanting to join, I am prepared to help them out.

A major seismic event could make even these preparations inadequate; but I think that we are more prepared than +90% of the Seattle area population. You can't prepare for every eventuality, you have to find the level of preparedness that makes sense to you and your neighborhood group.

MarkoNW said at May 26, 2010 12:16 PM:

Yep, ready here in Beaverton/Hillsboro. Have boxes of Mountain House #10 freeze dried food, water purification/filtration, shelter, etc.
My wife complains about it (esp. this week because we are moving), but knows that if we need it, we will really NEED it.

We are far enough from the coast that we don't worry about most tsunamis.

I saw Mt. St. Helens erupt from our back deck and have considered the risk for my entire adult life.

Claude Hopper said at May 26, 2010 12:44 PM:

I don't think Oregon is in the same earthquake league as Chile. In the last 110 years Chile has had 1 mag 9 EQ, 6 of mag between 8 and 9, 8 between 7 and 8 and 12 between 6 and 7. NW has had fewer and none so strong. If the NW has had 41 8+ EQs in 10,000 years (whistling Dixie here), proportionally Chile would have had 640. I can't say a major NW EQ will not happen tomorrow or next month, but since the subduction zone seems to be pushing a plastic media (note Mt St Helens ooze) it seems less likely than the OSU guy says.

Doug Collins said at May 26, 2010 12:47 PM:

A magnitude 9 Earhquake ???

Those are pretty rare.

NukemHill said at May 26, 2010 1:04 PM:

Your Carrington Event link is broken. You link back to this post (007200).

Tim McD said at May 26, 2010 1:29 PM:

Still broken, now you link to an index of all your archives, I am not going to go through all your old posts to find what you said about Carrington events!

Soviet of Washington said at May 26, 2010 1:40 PM:

Except for the new estimates of interval, most of this is older news.

You should add to the list that magnitude 7-8 quakes happen every 25-30 years from the faults around and under Puget Sound and Lake Washington (which are being compressed by the Cascadia Subduction Zone). These are as likely to create a significant disaster event in Pugetopolis as a mag 9 out on the continental margin, due to being much closer to the metro area and more frequent. Also, the Glacier Peak and Mt. Baker volcano's have significant lahar risks for the Skagit and Nooksack valleys.

MarkoNW, IIRC there's a pretty significant fault system that runs along Portland's West Hills as well. I would think a mag 7 under your feet wouldn't be out-of-the-question.

sestamibi said at May 26, 2010 3:06 PM:

Well, there goes my planned retirement move to Gold Beach, OR.

Check Carrington Event on Wikipedia.

Liz953 said at May 26, 2010 3:31 PM:

We have learned from Katrina and the current oil spill in the Gulf that during the first two weeks of any major disruption of human activity those who are experiencing it are the only ones who have control. This also applies in a terrorist event. Massive mobilization of shelter, food, water, tools, and medical help takes time, and people should not rely on "outside" or "government" help.
It behooves everyone - families and neighborhoods - to have a plan, and working together can consolidate costs and minimize loss of life (to the extent that is possible). Learn CPR and advanced first-aid. An alternative method of communication with the "outside" is critical. Cell phone batteries die, and assume cell networks will be crippled.
Finally, respectful treatment of the dead should be considered in the plan.

Rhoda R said at May 26, 2010 4:14 PM:

How can people living on the Gulf Coast not be prepared for a hurrican? Simple, they assume the gubbermt will step in and make everything just perfect.

Randall Parker said at May 26, 2010 4:49 PM:

The Carrington Event link is fixed.

Art Hyland said at May 26, 2010 6:15 PM:

Yes, and I've subscribed to Rush's "Bad Living Magazine" and am prepared as can possibly be. To be prepared for something like a 9.0 quake is to ruin your life. I'm ready at any moment with my digital camera. Yes, I know this was a serious question, but frankly, in this age of the Weather Channel turning into a permanent Storm Warning and Trajedy About Happen, I'm sick of the Global Warming Victimization of the Planet mode so many have adopted. I'm sure that when we're able to poke 10,000 mile camcorder cable into the center of the earth, we'll be totally freaked out at the predictions of doom. So let's stay calm, and be reasonable, and go with the statistics that say these things are fairly rare, so enjoy the long in-between periods for the joy they bring.

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