West Coast US - Quakes

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El and Bill

New member
During the past few weeks, the western side of the Pacific has suffered two major earthquakes - Christchurch and Japan. What can Brats living along the eastern margin of the Pacific learn from these quakes?

First: There are high odds that over the next 30 years the west cost of the continental US will suffer a massive earthquake similar to either of these quakes of this past week.

Second: The geology of the two quakes is different, but almost identical to our west coast.

1. Christchurch, New Zealand, was smashed by a large sideways slippage of a massive fault along a plate boundary largely inland, paralleling the coast. Several hundred people died and a third of the city was destroyed.

Southern California has a geologic situation almost identical - a large sideways slipping massive fault zone (the San Andreas) largely inland paralleling the coast.

Southern California has had, and will have, a massive earthquake similar to the Christchurch quake. No tsunami (probably), huge shaking destroying buildings and infrastructure. Extent of damage will depend on depth of quake (many on San Andreas are shallow, and hence more dangerous) and distance of epicenter from urban areas.

2. Sendai, Japan was destroyed and thousands killed by a head-on collision of two tectonic plates, with the heavier Pacific sea floor plate shoving beneath the Eurasian plate. The volcanoes of Japan are lighter density magma, melted from the subducting (sliding under) plate, punching up through the crust.

Oregon and Washington lie near the border of two tectonic plates (Juan de Fuca plate to the west and North American plate to east). These plates are in head-on collision, with the heavier Juan de Fuca plate (made up of heavy sea floor rock) shoving under the westerly moving continental (light density) North American plate. The volcanoes of the Cascades are lighter density magma, melted from the subducting Juan de Fuca plate, punching up through the continental crust.

Oregon and Washington have had massive earthquakes (last one the magnitude of the Japan quake (Richter 8.9) was January 26, 1700 (estimated R8.8-9.2) (dated by the tsunami it sent across the Pacific causing damage in Japan). Future large quakes along this zone would likely cause large tsunamis that would roll ashore within minutes of the quake. The site below illustrates the Oregon/Washington plate tectonic framework:

http://upload.wikimedia.org/wikipedia/c ... uction.jpg

Christchurch had a warning - a large earthquake the year before, less than a hundred miles west - and a statistical warning indicating frequency of quakes to be high.

Southern California has a similar statistical warning and a proximity of active fault zones to urban areas.

Sendai Japan had a few weeks of large (R6) earthquakes 40 miles offshore along the subducting edge of the Pacific plate before the big one - and a statistical warning.

Oregon/Washington has a statistical warning of probability and recently (last few months) a series of small (R4-5) offshore central Oregon.

In the event of a future large quake off the OR/WA coast, there would be only minutes of warning before a tsunami arrived compared with the several hours warning OR/WA residents had after the Japan quake.
 
From SCIENCE NEWS:

"All that you have to do is look at the footage from Japan and realize that is exactly what could happen here," said Patrick Corcoran, an Oregon State University education and outreach specialist who has been working with coastal communities for several years on earthquake and tsunami preparation.

"We may have 15 to 30 minutes between the time an earthquake hits and a tsunami arrives, so Oregonians shouldn't be lulled into a false sense of security," Corcoran pointed out. "What happened in Japan, in Chile, in Banda Aceh -- it will happen here. And it will be our turn to be in the bad place."

Corcoran works in Seaside on the northern Oregon coast where he said people were both "compliant and a bit confused" about the tsunami warnings. A few people went to emergency shelters, he said, and some 40 cars were parked at one evacuation site.

He said everyone living on the West Coast needs to expect the possibility of this type of event happening in our lifetime -- and to think specifically about what to do when an earthquake hits. The warning, he said, will be the earthquake itself.

"You need to drop and cover during the quake itself, and then immediately head to higher ground," Corcoran said. "Everyone needs to know specifically where to go -- whether you are at home, at work, out shopping or at your favorite bar. The general rule is to get to at least 50 feet elevation -- and 100 feet if you can.

"Families need to have plans -- for the parents and the kids -- and have those conversations today," he emphasized. "If the kids are at school and the parents are miles away, you have to trust that they will know what to do, or be told by their teachers to do the right thing, because you don't want parents crossing the inundation zone trying to reach their children. You have to have the discipline to stay put if you are safe -- and that discipline begins with being confident that all your family members know what to do in an emergency."

Scientists say there is more than a one-in-three chance that a major subduction zone earthquake will hit the Pacific Northwest in the next 50 years.
New analyses by OSU 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.

The damage from such a quake could be catastrophic. Corcoran said Northwest residents need to understand that massive, widespread damage will make personal attention by emergency managers unlikely.

"People need to take personal responsibility for preparing themselves and their families for this inevitable event," Corcoran said. "Prepared people not only help themselves, they can help their neighbors, too."

Robert Yeats, a professor emeritus of geology at OSU, agrees that Oregon is in better shape now than in 2005, when one of the last major tsunami warnings took place.

"Then you had a bunch of people running down to the beach to take pictures, acting like idiots," Yeats said. "It was sort of a fiasco. Oregon coastal communities seem to be better prepared now, even though there's still work to do. Our building codes for new structures are much better than they used to be.

"Right now, Oregon is probably a leader in tsunami preparedness on the West Coast -- although that still doesn't compare to the level of work they've done in Japan," Yeats added.

More information on tsunami preparedness is available through Oregon Sea Grant -- a marine education and outreach program based at OSU.

http://blogs.oregonstate.edu/breakingwaves/
 
In WA we are somewhat lucky in that much of our coast has fairly rapid increases in elevation close to the water. Hence we don't have much in the way of large towns on the W coast of WA that are not a good bit above sea level. However, Ocean Shores, Long Beach, Westport and Aberdeen have fairly large populations at low elevation close to the shore. This is in stark contrast to the area of Japan worst hit by the tsunami - they have large swaths of fairly shallow areas near the coast that were highly populated. Regardless, though WA would see some major damage and loss of life if a similar tsunami were to arrive on our coasts. It's a good idea for those who are visiting the coast to familiarize themselves with the tsunami evacuation routes. Those of us who are only out on the coast a few times a year might not know the best route to high ground from a marina or hotel.
 
I suspect with 30 foot waves that there would be some waterfront areas at risk in PNW--especially around the marina areas.

What warning systems are in place for WA, Org and Calif. Coast? Newport beach, Marina Del Ray etc would be at risk, as well as parts of Long Beach from a large Tsunami. The Calif. Delta could also be at risk--but wonder about any attenuation of the rise by the narrowing at Golden Gate? Would there be amplification up the bays--we had some of this during our large waves in the Gulf Coast during some of the major hurricanes.

There were studies with sensors in quake prediction--are there any developments in that area?
 
Does anyone know of a simulation program showing what a tsunami would do to the Puget sound and Victoria island? of all the cities in the area I think Victoria would be the worse hit. also what effect would the islands and turns in the sound do to the tsunami?? I would love to see a simulation of that.
 
There must be some statisticians out there. What does a 1 in 3 chance over the next 50 years break down to for a 1 month period?
 
Lived in Oregon between 1987 and 2005 in the Willamette Valley. We made frequent trips to the coast and became familiar with the entire coastal area. Of course all the beaches are owned by the state in Oregon so residential development has largely been confined to mostly the high ground. Yet, some how just out of Lincoln City on a spit have been built many homes. And while they are on stilts, they are a bulls eye for a tsunami. It appears that people with money can have their way, regardless how foolish it may be. Something like building a home on the flood plain. All the coastal marinas in Oregon are sitting ducks. It is just a matter of time.

John
 
Since both of my workplace clinics are at sea level, we rehearse complete clinic evacuation up a steep hill in a few minutes. The fault is supposedly 8 miles off shore. I have given our staff the Costco solar rechargeable flashlights to be kept near bedside. Hard sole shoes and helmet are also recommended. Many of the tribal community members have become CERT trained and several have ham license. Satellite radio and survival supplies are cached much higher as per USGS.

If you work or visit the coast: Mark the Tsunami exits on your GPS, if you are there on a regular basis, suggest you drive the Tsunami route to the end point so you are familiar w the terrain. I often mentally rehearse the what if it happens when I am in this spot routine.

My two favorite EDC "every day carry" devices for increasing survival odds:
Fenix LD01 Led light AAA - max 80 lumens 1 hr or 8 lumens 10 hrs. -waterproof to military standards, nearly same size as AAA battery

Tool Logic Knife, whistle, LED light, Magnesium fire starter

Bill I appreciate your information: USGS tells us the Aberdeen Tokeland area will first sink about 6 or more feet, as part of the subduction process. Then the Tsunami will arrive minutes later - your comments would be appreciated.

Also please comment about the wrap around effect of a coastal Tsunami on South Puget Sound. I am aware of the Bremerton Seattle I90 fault - that poses other significant risk.

Thanks
Jim
 
Does anyone wonder about the advisability of more nuclear plants especially in earthquake zones? The new technology is said to be safe but it ticks me off that congress has put tax payers on the hook for any disaster. IMHO the companies should accept liability just like in capitalist economies.Seems like large corporations and government are becoming one and the same.
 
Simplicity":kym8hjbv said:
Does anyone wonder about the advisability of more nuclear plants especially in earthquake zones? The new technology is said to be safe but it ticks me off that congress has put tax payers on the hook for any disaster. IMHO the companies should accept liability just like in capitalist economies.Seems like large corporations and government are becoming one and the same.
Click to expand...

We'll see what the end result of this is. If, as is anticipated, there is a meltdown or partial meltdown with very little release of radiation, then the current worries will add little to the argument about whether or not nuclear power is safe. Also, we have to consider safety in relative terms - e.g. compared to the number who die from say, coal mining and the environmental effects thereof. I know of no source of power that is 100% safe.
 
Simplicity I might point out that San Onofre Nucular station was not paid for by any tax dollars. I believe that is also true of Diablo Canyon reactor. These and a number of others were built by private companies (S. Cal. Edison and P G & E) What is the risk? It is really unknown until it occurs. However, in Calif. at least, the private utilities tried to avoid very high population centers, and needed the cooling water from the ocean. Cooling water is essential for the current group of nuculear power plants. Maybe not in the future?

I might point out, that I spent the first few years of my life living on the grounds of Edison Company steam generating plants. The horror played out every few years when a boiler exploded, killing empolyees. My father was an operator at those plants and was at risk. Even today people are killed in the coal miles and in petrolium rigs. How many people have been killed by nuculear power plants in the US? Or even injured or developed cancer? I agree that this accident has set back nuculear power. But there are problems with every type of power generation--and no simple solution for our needs. With electric cars, this only increases the demand for electric power. No easy solution.
 
One of the problems of nuclear reactors is that fire and homeowners insurance does not cover any damage caused by radiation, or nuclear contamination in any way. So if the nuclear reactor goes off, only the fed government will pay for damage, and perhaps they won't. The only exception is for fire resulting from nuclear radiation or meltdown, and then only for the resulting fire damage.

So the private companies get the profits, and we, the people, take the risks, both to our health, and to our property.
 
So the private companies get the profits, and we, the people, take the risks, both to our health, and to our property.
Click to expand...

Just who is the "Private company"? Edison International (78%) San Diego Gas and Power (20%), and City of Riverside (less than 2%--mandated by deregulation--no real buy in). All employ thousands of people in S. Calif. who are the "Company". Diablo Canyon is owned by PG & E. There are also the investors--thousands of us who openly own stock in these companies and many thousands more who own these companies thru pension plans, 401's etc. (including state plans). So the company is you the average citizen, but you don't know it.

Yes the Chairman of the BOD of Edison makes a good salary, plus options--but so does any other executive (and some far more) which run companies of this size and complexity. More important is the many workers who run from pick and shovel on up to lineman and folks who do the engineering etc. These are fianced by public bonds and stocks upon which interest has to be paid. The company has to spend millions to comply with various government regulations and permitting. Also many millions for maintance, upgrades and new generation/transmission facilities. The company pays huge amounts of taxes and their contribution to the economy is immense, way beyond the dependable supply of power to your home.

The company has risks of law suits--such as against PG&E for the gas explosions in Daly City. (You would be surprised at the number of suits which are filed about right of way, radiation etc each year against these companies--all costs of doing business). The company cannot make out I O U's or print money--it has to compete in the real world.

Your house is most likely not insured for earth quakes (or if it is, it is very costly). The cost of nuculear power at San Onofre is less than 20% of petroleum products, 30% of the cost of Coal, 50% of the cost of Natural Gas, and adds minimal to polution of the air and environment in S. Calif--something all of the other forms (except hyrdo power) contribute to significantly, despite all efforts.
 
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