Posted on 03/16/2022 8:28:58 PM PDT by BenLurkin
The San Andreas Fault has three sections. The southern section runs from the Salton Sea to Parkfield, California, and has the capacity for large quakes. In 1857, for example, the magnitude-7.9 Fort Tejon quake shifted the ground at the fault a whopping 29.5 feet (9 meters). The northern section of the fault runs from the town of Hollister, through the Bay Area up to Cape Mendocino, California. This section of the fault is most famous for the great 1906 San Francisco earthquake, which had an estimated magnitude of 7.9.
The researchers analyzed a sediment core from the central San Andreas that was drilled as part of the San Andreas Fault Observatory at Depth (SAFOD) project. Deep in the core, about 1.9 miles down (3,192 to 3,196 meters), the researchers found a spot where the biomarkers showed signs of heating.
Next, the researchers analyzed the quake-deformed section of rock with a method called potassium-argon dating. This method takes advantage of the fact that a naturally radioactive variation of potassium, potassium-40, slowly decays into argon gas. When something happens to heat the rock, this gas is released, resetting the "potassium-argon clock" to zero. By looking at the accumulation of argon, the researchers could determine how long it had been since the rocks were heated.
Part of the ongoing work done by Coffey's collaborators involves improving the potassium-argon method for earthquake dating to narrow down that time span. However, the magnitude of the heating indicates that the central San Andreas can indeed undergo a lot of shaking — it's likely that the earthquakes recorded in this section of the fault ranged from magnitudes in the mid-6s to low-7s, Coffey said.
(Excerpt) Read more at livescience.com ...
Not my fault, I didn’t do it.
I remember that movie.
The theme song by duran duran was good too.
https://m.youtube.com/watch?v=Fp4CR2HcHLQ
I just watched that movie last Nite.. San Andreas!
I guess that’s the thrust of your argument.
Just business as usual along the fault as in the past. If your buildings are not designed for the fault they will fall down. Not trying to be funny but that is reality.
“charlie the geologist and pharmacist.”
Anything that can move everything up, down and sideways 29.5ft is going to topple every building.
Compressed form, yes.
Hope nothing slipped by.
for later
Wonder if they shear sheep out there.
California tumbles into the sea,
that’ll be the day I do back to Annandale.
I am sure that in 1857 the earthquake monitoring devices were state of the art. So that seven point something is more than just a guess.
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