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Wed May 11, 2016, 02:09 PM

 

San Andreas fault is about to crack – here's what will happen when it does

http://www.upi.com/Top_News/Opinion/2016/05/11/San-Andreas-fault-is-about-to-crack-heres-what-will-happen-when-it-does/6741462974519/

The director of the Southern California Earthquake Center, Thomas Jordan, made an announcement recently that would have sent a chill down the spine of every Californian: that the San Andreas fault appears to be in a critical state and as such, could generate a large earthquake imminently.

Of course, the reiteration of the seismic hazard to Californians will be nothing surprising, but what is new is the warning that the southern portion of the fault "looks like it's locked, loaded and ready to go."

Why is this eminent seismologist making these alarming statements? Well, the fact is that there has not been a major release of stresses in the southern portion of the San Andreas fault system since 1857. In simple terms, the San Andreas is one of many fault systems roughly marking the border between the Pacific and North American tectonic plates. Both plates are moving in an approximately northerly direction, but the Pacific plate is moving faster than its North American counterpart, meaning that stresses between the plates are constantly building up.

In 1906, some of these stresses were catastrophically released in the San Francisco Bay area in a 7.8 magnitude event and again, in northern California, during the 6.9 magnitude 1989 Loma Prieta earthquake. Events of these magnitudes, however, have not occurred along the San Andreas fault in the south of the state – the 1994 Northridge event was associated with a nearby, but separate, fault system – leading to the suggestion that one is imminent and, given the amount of stress that might actually have accumulated, when it arrives it will be the "Big One."

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Arrow 21 replies Author Time Post
Reply San Andreas fault is about to crack – here's what will happen when it does (Original post)
KamaAina May 2016 OP
MattP May 2016 #1
thereismore May 2016 #2
KamaAina May 2016 #3
Protalker May 2016 #4
KamaAina May 2016 #5
Protalker May 2016 #9
shanti May 2016 #10
Lordquinton May 2016 #6
Galileo126 May 2016 #7
hvn_nbr_2 May 2016 #8
Retrograde May 2016 #12
LeftyMom May 2016 #11
yuiyoshida May 2016 #13
KamaAina May 2016 #14
yuiyoshida May 2016 #15
KamaAina May 2016 #16
yuiyoshida May 2016 #17
Brother Buzz May 2016 #18
hunter May 2016 #19
Brother Buzz May 2016 #20
DesertRat Jun 2016 #21

Response to KamaAina (Original post)

Wed May 11, 2016, 02:20 PM

1. I remember in 81 my school would have earthquake drills

And everybody would say the big one is going to hit any day now. The building next door to me fell down during the Landers quake.

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Response to KamaAina (Original post)

Wed May 11, 2016, 02:33 PM

2. I wonder, if it's so loaded and ready to go, why it didn't unload after the 1989 earthquake.

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Response to thereismore (Reply #2)

Wed May 11, 2016, 02:43 PM

3. That was on the northern section of the fault.

 

The concern is for the southern section, which hasn't gone off since 1857 and runs right, and I mean right above San Bernardino.

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Response to KamaAina (Original post)

Wed May 11, 2016, 02:46 PM

4. Paradise aka San Diego

I love to visit my friends 23rd floor overlooking the Bay. All life involves risk. Live for today.

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Response to Protalker (Reply #4)

Wed May 11, 2016, 02:54 PM

5. San Diego is pretty far from the San Andreas

 

Don't know if there are any local faults down there like L.A. and the East Bay have, though. The main hazard in SD seems to be wildfire.

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Response to KamaAina (Reply #5)

Wed May 11, 2016, 08:58 PM

9. Thanks for relatively good news.

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Response to KamaAina (Reply #5)

Thu May 12, 2016, 07:06 PM

10. temecula

in southern riverside county, has the lake elsinore fault line, and is fairy close to sandy eggo.

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Response to KamaAina (Original post)

Wed May 11, 2016, 03:49 PM

6. In a geological scale

Immediately means anywhere between now and 1000 years (or more).

Just like any Californian, have the earthquake kit prepared and up to date.

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Response to KamaAina (Original post)

Wed May 11, 2016, 03:51 PM

7. It has been pretty quiet in the High Desert

and I live just 1.5 miles from the fault. All we've been getting is 1-2 mag range microquakes.

A couple of 5.0's would help some... or not?

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Response to Galileo126 (Reply #7)

Wed May 11, 2016, 04:22 PM

8. I don't think 5.0's would do anything to help

Since the scale is logarithmic, it would take 10X 5.0 quakes to release the stress of one 6.0, and 100X 5.0's to release the stress of one 7.0.

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Response to hvn_nbr_2 (Reply #8)

Fri May 13, 2016, 08:29 PM

12. Probably not, but they would make people more aware that the faults are there

Some months before Loma Prieta we had a number of smaller quakes. Very little damage, but as a result I did bolt the bookcases to the wall, and made sure nothing breakable was near the bed. It's just been too quiet in the Bay Area, and with the new influx of residents who've never experienced a big enough quake and don't know what precautions they can take to reduce damage I'm afraid that when we do get a largish one it will be worse due to lack of preparation.

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Response to KamaAina (Original post)

Fri May 13, 2016, 06:58 PM

11. Every now and then it's nice to live in The Town Where Nothing Ever Happens*

*except an attempted Presidential assassination, an SLA bank robbery, the occasional serial murder, more than our fair share of hostage situations, innumerable catastrophic floods, and that Cake cover of War Pigs. But no earthquakes.

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Response to KamaAina (Original post)

Mon May 16, 2016, 03:30 PM

13. The thing is part of the fault goes out into the pacific

That mean's a tsunami, maybe similar to what Japan faced.

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Response to yuiyoshida (Reply #13)

Mon May 16, 2016, 03:47 PM

14. I believe that's the northern section

 

The 1906 quake's epicenter was actually just off SF.

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Response to KamaAina (Reply #14)

Mon May 16, 2016, 04:29 PM

15. look again...

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Response to yuiyoshida (Reply #15)

Mon May 16, 2016, 04:45 PM

16. The one offshore appears to be the northern San Gregorio.

 

https://en.wikipedia.org/wiki/San_Gregorio_Fault

The San Gregorio Fault is an active fault located off the coast of Northern California. The southern end of the fault is in southern Monterey Bay, and the northern end is about 20 km northwest of San Francisco, near Bolinas Bay, where the San Gregorio intersects the San Andreas Fault. Most of the San Gregorio fault trace is located offshore beneath the waters of Monterey Bay, Half Moon Bay, and the Pacific Ocean, though it cuts across land near Point Año Nuevo and Pillar Point. The San Gregorio Fault is part of a system of coastal faults which run roughly parallel to the San Andreas.

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Response to KamaAina (Reply #16)

Mon May 16, 2016, 04:56 PM

17. There are three listed off shore from the city

1.) Northern San Gregorio
2.) San Andreas Santa Cruz
3.) San Andreas Northern Golden Gate

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Response to yuiyoshida (Reply #13)

Mon May 16, 2016, 08:11 PM

18. The San Andreas is a strike-slip fault and generally doesn't create much of a tsunami

It's those underwater upthrusting faults that will get you

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Response to Brother Buzz (Reply #18)

Mon May 16, 2016, 11:06 PM

19. Except that the terrain is steep and subject to landslides.

Land sliding under the ocean can make big waves.

Such landslides can be spontaneous or initiated by earthquakes.

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Response to hunter (Reply #19)

Mon May 16, 2016, 11:24 PM

20. True

The Storegga slide, the granddaddy of all slides, comes to mind

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Response to KamaAina (Original post)

Wed Jun 1, 2016, 11:42 AM

21. That is truly terrifying

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