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Newly Discovered Fault Under L.A.
Randolpho writes "Whether you like the city or not, you can't say Los Angeles doesn't have a fault. It does, and it's one of earth-shattering proportions. Geologists have confirmed that LA was built right over a faultline, which they're calling the Puente Hills Blind Thrust System; it runs from northern Orange County through Los Angeles on up to Beverly Hills, and has a habbit of ripping earthquakes as large as 7.5 on the Richter Scale every 10 thousand years or so. And the last one was about 8 thousand years ago."
CNN has an article on this new fault that is slightly less confusing. You can find it here.
Impersonating Tycho from Penny Arcade since before there was a PA.
This is silly - if not FUD for grant money.
The LA basin is about 1 to 30 kilometers of rubble on top of a very active basement of solid rock which is riddled with active faults like a piece of dropped china is riddled with cracks. All of the rubble (alluvium) makes it hard to see active faults as they are buried deep.
Basically every big earthquake that LA has experienced (with the exception of the large one the San Andreas fault in the 1840's) has been on a previously unknown fault.
So, earthquakes happen, but our ability to tell exactly where they will be is near nil.
>The only thing of note is that this puts to rest the thought that blind thrust faults cannot exist
I don't think the existence of blind thrusts has ever been a question. Structural geologists have been quite aware of that type of structure for some time. Indeed, the question isn't even if blind thrusts are a seismic problem -- the Northridge earthquake in 1994 was on a blind thrust. The problem with blind thrusts is that there is no easy way to tell where they are, principally because (by definition) they don't "daylight" i.e. reach the surface. The cool thing about this study is that paleosiesmologists have documented a previoiusly-unknonwn blind thrust fault in an urban area (a major seismic hazard) using well data and geophysics. Not only that, but they mananged to place constraints on it's prior movement history and its recurrence interval. A nice piece of important work.
It could be worse: it could be Seattle (an earthquate caused by Juan de Fuca plate movement could cause a Tsunami AND erupt that little ol' volcano they have just outside the city).
Not to mention the potential strength of the next "Big One" in the Seattle/Vancouver area. 8 Million people, suddenly swimming...
The Cascadia Megathrust Event is due.
Fascism should more properly be called corporatism, since it is the merger of state and corporate power.