The Big One

[catsmate]

Nope, not the San Andreas but the Cascadia subduction zone.
Starting here there is a six part series of articles on the effects of a major earthquake and tsunami along the US west coast.

Earthquakes along the fault have happened forty one times in the last ten thousand years, based on data from core samples from the seabed. That's an average interval of 243 years. The last major slip was in 1700, 316 years ago...
Of course the fact that such an earthquake is statistically "overdue" isn't a predictor of an imminent geological event. But it is interesting.
In a 2009 study geologists predicted probability in the region of 10-14% probability that the Cascadia Subduction Zone would produce an event of magnitude 9.0 or higher in the next 50 years while a other studies, concentrating on the southern portion, suggested that the probability could be as high as 35% for smaller earthquakes, of magnitude around 8.0.

If the entire CSZ were to give way the resulting earthquake would be enormously powerful, in the region of magnitude 8.7 to 9.3, and one of the most powerful in recent centuries. If only the southern portion of the zone were to gives way the magnitude of the resulting quake would be in the 8.0 to 8.6 region.


If anyone's interested in a realistic version of a major San Andreas quake I suggest you look at the ShakeOut Scenario, a USGS led study and model of such a quake.

 

[Trebuchet]

Thank you SO much for reminding me where I'm living.....

Fortunately if it holds off for about 40 years I won't be here to care.

 

[Shalamar]

Thank you SO much for reminding me where I'm living.....

Fortunately if it holds off for about 40 years I won't be here to care.

Yup. I'm out here as well.

If it happens, well, I'll likely be dead.

 

[Newtons Bit]

Yup. I'm out here as well.

If it happens, well, I'll likely be dead.

You'll probably be fine. This article seriously smacks of alarmism.

Unless you live or work in an old unreinforced masonry building. Then you're boned.

 

[Shalamar]

You'll probably be fine. This article seriously smacks of alarmism.

Unless you live or work in an old unreinforced masonry building. Then you're boned.

Actually, I work at one of the major hospital chains. So I'd be set for medical help!

 

[Crossbow]

We have to make sure that Lex Luthor does not find out about this information.

 

[deadrose]

Having spent most of my life in earthquake-prone zones, I'm okay with my chances. I'd rather live here than the Gulf Coast (hurricanes) or Tornado Alley. Guess it's the devil I know.

But in old masonry buildings I tend to look for the nearest open ground or sturdy table

 

[RussDill]

There are similar overdue concerns in socal:

http://www.latimes.com/local/lanow/la-me-ln-san-andreas-fault-earthquake-20160504-story.html

The general reminder on both stories is that earthquakes aren't like many other disasters. There is never a question of if a fault will rupture, only when.

 

[cullennz]

Over due can mean it could happen in about 400 years

 

[dudalb]

Having spent most of my life in earthquake-prone zones, I'm okay with my chances. I'd rather live here than the Gulf Coast (hurricanes) or Tornado Alley. Guess it's the devil I know.

But in old masonry buildings I tend to look for the nearest open ground or sturdy table

As a native Californian, I agree. Just look at the number of killer earthquakes as opposed to killer Tornados or Hurricans. I will take my chances with Earthquakes any day of the week.

And a good part of Tornedo Country in the Midwest is also sitting on top of a fault zone that has been inactive for a long time;of the worst recorded earthquakes in history..The New Madrid Quakes in 1811 and 1812.They changed the course of the Mississippi ,for heaven's sake. So you have double jeopardy.
And the Midwest states do not have a lot of the Earthquake safety laws that California does. A big quake will hit there some day, and it will be pretty bad.

 

[dudalb]

We have to make sure that Lex Luthor does not find out about this information.

Or Max Zorin (Christopher Walken) in "A View To A Kill".

 

[bytewizard]

I live a few miles from the San Andreas fault, lived through the 89 quake with major structural damage but no personal injuries. Rebuild and be ready for another because it will happen, hopefully not for many years. I don't feel like rebuilding again.

 

[cullennz]

Pretty hard not to be near a fault line here

 

[Solitaire]

And a good part of Tornedo Country in the Midwest is also sitting on top of a fault zone that has been inactive for a long time;of the worst recorded earthquakes in history..The New Madrid Quakes in 1811 and 1812.They changed the course of the Mississippi ,for heaven's sake. So you have double jeopardy.
And the Midwest states do not have a lot of the Earthquake safety laws that California does. A big quake will hit there some day, and it will be pretty bad.

Yes, this one worries me the most because it's only 1000 km away through
a lot of old very conductive rock. They get an 8.0 then I get a 7.0 later on.
The rock in California is broken up and and not that conductive.

 

[catsmate]

You'll probably be fine. This article seriously smacks of alarmism.

In what way? Given that it's based on the projections from FEMA and OSSPAC, and on the best seismic data available, from people like Chris Goldfinger, I'd like to see your detailed criticisms.

For example, Kenneth Murphy (FEMA’s Region X division director)
"Our operating assumption is that everything west of Interstate 5 will be toast".

Unless you live or work in an old unreinforced masonry building. Then you're boned.

Oregon has extremely poor seismic preparation, mainly down to the recentness of the discovery of the implications of the CSZ.
In fact it was only in 1974 that the state of Oregon instituted any seismic code. The vast majority of buildings in the region were constructed before then. For example Ian Madin (Oregon Department of Geology and Mineral Industries) estimates that 75% of all structures in the state are not designed to withstand a major Cascadia quake. Accross the region more than one million buildings will collapse or be compromised in the earthquake.
3,000 of those are schools.

Also liable to collapse are around half of all highway bridges, fifteen of the seventeen bridges that span Portland rivers, 65% of railways and airports, 35% of fire stations, 55% of police stations and 60% of all hospitals.

Then there's the fascinating phenomena of liquefiable land, where seemingly solid ground starts behaving like a liquid. Not good for anything on top of it.
In Portland such liquefiable land carries the pipelines carrying 90% of of the state’s liquid and gaseous fuel, along with electrical substations and natural gas terminals. Remember about 90% of the fatalities in San Francisco in 1906 were due to fires.
Fifteen per cent of Seattle (housing 35,000 people) is also built on such ground.

It's only since 1995 that Oregon has restricted construction in the inundation zone, but this only applies to new construction of schools, hospitals, fire and police; those already there can stay. Plus other new construction is allowed, be it energy facilities, hotels, retirement homes or anything else.

 

[cullennz]

In what way? Given that it's based on the projections from FEMA and OSSPAC, and on the best seismic data available, from people like Chris Goldfinger, I'd like to see your detailed criticisms.

For example, Kenneth Murphy (FEMA’s Region X division director)
"Our operating assumption is that everything west of Interstate 5 will be toast".


Oregon has extremely poor seismic preparation, mainly down to the recentness of the discovery of the implications of the CSZ.
In fact it was only in 1974 that the state of Oregon instituted any seismic code. The vast majority of buildings in the region were constructed before then. For example Ian Madin (Oregon Department of Geology and Mineral Industries) estimates that 75% of all structures in the state are not designed to withstand a major Cascadia quake. Accross the region more than one million buildings will collapse or be compromised in the earthquake.
3,000 of those are schools.

Also liable to collapse are around half of all highway bridges, fifteen of the seventeen bridges that span Portland rivers, 65% of railways and airports, 35% of fire stations, 55% of police stations and 60% of all hospitals.

Then there's the fascinating phenomena of liquefiable land, where seemingly solid ground starts behaving like a liquid. Not good for anything on top of it.
In Portland such liquefiable land carries the pipelines carrying 90% of of the state’s liquid and gaseous fuel, along with electrical substations and natural gas terminals. Remember about 90% of the fatalities in San Francisco in 1906 were due to fires.
Fifteen per cent of Seattle (housing 35,000 people) is also built on such ground.

It's only since 1995 that Oregon has restricted construction in the inundation zone, but this only applies to new construction of schools, hospitals, fire and police; those already there can stay. Plus other new construction is allowed, be it energy facilities, hotels, retirement homes or anything else.

Liquefication basically stuffed half of Christchurch

 

[Trebuchet]

We are currently living in a 1974 mobile home overlooking Discovery Bay and the Strait of Juan De Fuca. We'll be able to see the tsunami coming. The "house" is sitting on stacks of cinder blocks and not even tied to the ground. But if the big one holds off for a year we should have the new house built. Fortunately we're about 300 feet above the sea.

 

[RussDill]

We are currently living in a 1974 mobile home overlooking Discovery Bay and the Strait of Juan De Fuca. We'll be able to see the tsunami coming. The "house" is sitting on stacks of cinder blocks and not even tied to the ground. But if the big one holds off for a year we should have the new house built. Fortunately we're about 300 feet above the sea.

I wonder how many feet above the sea these trees were before the land they were on dropped during a cascadia quake.

 

[catsmate]

We are currently living in a 1974 mobile home overlooking Discovery Bay and the Strait of Juan De Fuca. We'll be able to see the tsunami coming. The "house" is sitting on stacks of cinder blocks and not even tied to the ground. But if the big one holds off for a year we should have the new house built. Fortunately we're about 300 feet above the sea.

You might not be afterwards...
If the Big One hits there's projected to be a significant (10-30m) landslip.
You might be able to see the plume from Oregon's "Critical Energy Infrastructure Hub" burning from there.

Here's an article on how to survive.

 

[Trebuchet]

You might not be afterwards...
If the Big One hits there's projected to be a significant (10-30m) landslip.
You might be able to see the plume from Oregon's "Critical Energy Infrastructure Hub" burning from there.

Here's an article on how to survive.

Yup. We might survive the tsunami, but not the other effects. Which is why I'm banking on it holding off for forty years, when I'll most likely be gone.