The Cajon Pass Hell Gate

[IdeomotorPrisoner]

https://www.livescience.com/planet-earth...tudy-finds




The Big One is still coming, at some point, probably waiting for the tribulation, but Southern California is fucked when it happens. 

A new study of 1000 years of earthquake data is showing two connected faults, The San Andreas and San Jacinto are at their highest point of stress in the entirety of the study.

Where they come together, it looks like this:



The red line in The Southern Mojave Segment of The San Andreas.

The orange line that it continues into is the North San Bernardino Segment of The San Andreas.

The orange line veering off from that is the end of The San Jacinto Fault.

The scary part is both major faults are at such maximum states of stress, the likelihood of one triggering the other is at it's highest point as well.

Its considered like a gate. And whether it opens to stress transfer relies entirely on how stressed each fault is. 

Though the two faults never intersect (coming within 1 km), there are smaller faults like The Glen Helen (also orange) which parallels both, and acts like a seismic bridge between the two dominant fault lines. 

You actually dont need any knowledge beyond that to understand how this all can end in worst case scenarios on multiple faults. 

The 30 year lull is going to REALLY end and hard. 

10 million are living on top of a bomb waiting to explode. And 13 million more in the shake zone.

Good luck LA Basin, Inland Empire, Antelope Valley, and Coachella Valley.

Freeways are going to collapse, but my fear is for the soft story dwellers. They are illegal to build today, but there are 4000 to 6000 unretrofitted ones still inhabited in extreme seismic hazard zones. MMI VIII shaking can take them down. So in the "big one" scenario ALL 6000 are a partial or full collapse risk..

Glad we only get MMI VI or VII intensity where I am. Thankful I am not in the infill liquefaction areas either. 

 Though Winter the earthquake has been coming for 40 fucking years now, it stays locked up building to stress levels never seen in modern history. 

It is at its most stressed point since The Mississippian City of Cahokia was at its peak population. Braveheart was still 150 year from existing. Paris had 3,000 to 10,000 inhabitants and was recovering from murderous Viking raids.

It's almost like a watch fault never slips... and this fault is trolling us like it did in Parkfield.

* fixed roman numerals.
* checked retrofitting stats and how many are left inhabited

[worldstarcountry]

Well this is disturbing. Could a Bore hill be drilled down and an explosive event trigger this release of stress??

[ArMaP]

Although I'm a fan of science, how can they really know the stress levels from 100 (or even 300) years ago?

I suppose they can make calculations based on the evidence from previous earthquakes, but 1000 years ago there wasn't any way of measuring earthquakes and, as far as I know, no records of earthquakes in North America.

PS: I live in an area where we are also hoping the next big one doesn't happen, the 1755 Lisbon earthquake was the last really big one we had, although the 1969 earthquake was big enough to destroy a few buildings.

[andy06shake]

Well this is disturbing. Could a Bore hill be drilled down and an explosive event trigger this release of stress??

The San Andreas fault line runs for hundreds of miles.

And it's about 6-9 miles deep.

I don't think our explosives would affect it much...

Never mind how we would get them down that deep.

[IdeomotorPrisoner]

Although I'm a fan of science, how can they really know the stress levels from 100 (or even 300) years ago?

I suppose they can make calculations based on the evidence from previous earthquakes, but 1000 years ago there wasn't any way of measuring earthquakes and, as far as I know, no records of earthquakes in North America.

PS: I live in an area where we are also hoping the next big one doesn't happen, the 1755 Lisbon earthquake was the last really big one we had, although the 1969 earthquake was big enough to destroy a few buildings.

Same old modern geological methods as always. Radio carbon dated sediment layers and tree rings all fed into a computer model.

The site looked at specifically is The Wightwood Paleoseismic Site about 8 miles from the "Hell Gate," in the San Gabriel Mountains. 

Over the last 1500 years there have been 14 "big ones" identified using these indirect approximation methods.  Like figuring out Cascadia's last major event was in 1700 by dating coastal ghost forests and sediments up the Columbia River.

In the San Gabriel mountains they dug trenches across the fault and looked for buried organic material trapped by ground displacement. Or if the earthquake shifts a trees angle, the tree will compensate by growing thicker rings on the compromised side, which can be dated. 

Just read about The Azores-Gibraltar Tranform Fault.  Also a mostly strike/slip boundary with thrust and reverse sections. Key difference seems to be the AGFZ runs 50 km offshore instead of on land.

[Randyvine]

[Image: https://denyignorance.com/uploader/image...f69a94.jpg]

I don't wanna crap on your thread. But I been watching here and there
and I get the impression that even the janitor at USGS is posting doom
porn these days. The money grab on you tube together with AI has
rendered the entire interlink undiscernible because apparently BS sells
better than truth. Then again the mentioned faults are sure to be a
complete catastrophe at some point. Anywhere from today going forward.
And it is going to suck really bad. Not if but when?

I take it you live in the area?

[IdeomotorPrisoner]

Well this is disturbing. Could a Bore hill be drilled down and an explosive event trigger this release of stress??

That's kinda like trying to stop a supervolcano by trying drain it with a nuked pressure valve. 

This is at critical levels with nothing to do but let it go when it wants to..

From the Coachella Valley to The Big Bend the fault runs more Westerly, then bends sharply North, like a plate boundary snag on the continents. 

And where this study was done is a mountain chain that was also snagged by this "big bend" and rotated 110° by the motion of the plates to run East-West instead. (Transverse Ranges).

Because the main fault follows a westward path through this area, the northwest-moving Pacific Plate collides directly into the westward-moving North American Plate. This "oblique convergence" (transpression) forces the crust to crumple upwards and outwards.  

So basically THE EXACT SAME forces that created the Transverse Ranges at the Big Bend are still all there trying to rip the land west of the fault around the Bend and North towards the bay area.

And this pass is the critical point south of the bend north itself where all these forces squeezing and pulling different directions meet.

[IdeomotorPrisoner]

I don't wanna crap on your thread. But I been watching here and there
and I get the impression that even the janitor at USGS is posting doom
porn these days. The money grab on you tube together with AI has
rendered the entire interlink undiscernible because apparently BS sells
better than truth. Then again the mentioned faults are sure to be a
complete catastrophe at some point. Anywhere from today going forward.
And it is going to suck really bad. Not if but when?

Isn't that how old school ATS was?

Doom porn all the way, but its really really overdue doom porn. 

... But  did you know The San Andreas has a little sister plate boundary called Walker Lane? Recent studies show 20-25% of the total movement has shifted (or always was shifted) to the East. 

This is now sometimes called the Sierra Nevada Microplate (or Great Valley Block) bouded by The San Andreas (west), Garlock Fault (south), Walker Lane (east), and Sierra Nevada-Cascade Boundary Zone (North).  Still under debate. 

While both San Andreas and Walker Lane accommodate overall plate motion, the models may not always add everything that factors.  Like The San Andreas only absorbing 75-80% of the overall motion. 

And the janitor can only do that they can look up Wikipedia and then understand it, or make a self-labeled map, which science says needs to be scrutinized.

[Randyvine]

Isn't that how old school ATS was?

Doom porn all the way, but its really really overdue doom porn. 

... But  did you know The San Andreas has a little sister plate boundary called Walker Lane? Recent studies show 20-25% of the total movement has shifted (or always was shifted) to the East. 

This is now sometimes called the Sierra Nevada Microplate (or Great Valley Block) bouded by The San Andreas (west), Garlock Fault (south), Walker Lane (east), and Sierra Nevada-Cascade Boundary Zone (North).  Still under debate. 

While both San Andreas and Walker Lane accommodate overall plate motion, the models may not always add everything that factors.  Like The San Andreas only absorbing 75-80% of the overall motion. 

And the janitor can only do that they can look up Wikipedia and then understand it..

It won't be just the quake that kills that's for sure. The aftermath will be
gas explosions and fires and rescues going on. And on top of that a mass
exodus going out the 15 fwy, holy crap like the 15 isn't bad enough already.

[IdeomotorPrisoner]

Its going to be a Northridge on a scale like Little Boy compared to the Tsar Bomb.

*If* (or when) both these faults go in rapid triggered successes the ground faulting, ultily displacement, overall infrastructure damage will be massive.  2 minutes of jello and liquefaction in the basin, ground shifted several feet in The IE.  

A 200 mile surface rupture is expected.  

So basically this, only through Inland Empire subdivisions: 




Its the Looming Greater Los Angeles Apocalypse. 

As for the 15?  

That pass through seemingly continuous mountains blocking a direct route route between San Bernardino and Barstow really was too good to be true.  

And been lucky its entire existence to not be really tested.