reply to post by zworld
In case some readers might think you're exaggerating I'd like to back up at least some of what you're saying. It's a matter of scientific record
that the megathrust event of Jan 26, 1700, off the coast of the PNW generated a tsunami that definitely reached 30 metres in some places. (For anyone
who's not used to metric, that's pushing close to 100 feet.) It's also generally accepted by the scientists who studied this event that a future
megathrust along the same subduction zone could involve a fracture 600 kilometres long or more. (Around 400 miles.)
If there are demands for evidence and links, then I can proivide them. Or others on the thread can who've got the same data I have. But I assure all
readers that the CSZ (Cascadia Subduction Zone) is a real beast.
It is also known that there have been several events in this region in the past, at varying intervals. I recall figures with a low interval in the
region of about 200-odd years and up to around 1,000 years. I'd have to check my references for more precise details. However a few years here or
there don't really matter because the point is -- as zworld says -- these things let go when they let go. If anyone hears or reads that the CSZ is
"overdue" then I'd point out that a subduction zone is not a bus or a baby. It's not running to some preset timetable and so terms like
"overdue" are misleading and unscientific. The only thing we know is that it has already been 311 years since the last big one there, and there have
been previous events at shorter intervals than that.
Here's the simple truth: the CSZ could let go with a massive, megathrust event at any time. It could happen right now, or tomorrow, or next month. Or
it could be in a year, ten years, or even a couple of centuries. But it is almost certain that one day, it is going to let go and when it does, all
previous seismic events experienced within the USA since its founding will pale into insignificance in comparison. Not even the huge Alaska quake in
the 1960s comes close, as that was a far more localized event in terms of movement than this megathrust event is going to be.
I am not saying this to scaremonger. If you tell your kids to look both ways before crossing the street so they don't get run down by a car, is that
scaremongering? No, it's giving them the plain truth to help them stay alive. Stating the facts is not scaremongering. And even if you live in a
quiet area, you still tell them to check the road, right? Sure, they could look both ways many times and never see a car close by, but does that mean
they should stop looking? No, because Murphy's Law says the one time you don't look, that's when the car will come barrelling down the road.
Not seeing it won't help you if it hits you.
This is the same. There are many, many people who sincerely believe the "big one" is going the be an event on the San Andreas fault system
somewhere. But a megathrust on the CSZ could release more
than 1,000 times energy than the Loma Prieta quake of 1989. We're talking about mag
9-plus versus the Loma Prieta's mag 6.9 or 7.0 (depending on sources). One thousand times more energy. In land regions near the megathrust, there
will be violent shaking that can last for several minutes, non-stop: and it will be shaking 100 times stronger than Loma Prieta did.
The San Andreas is not
the "big one". It's bad, yes, but the real
big one lies offshore, and that's the worry, because while it
might be centered offshore, the plate moves under the land, right down from Washington, through Orgeon, and into northern California. It might even
extend further south. We don't know. No-one knows for sure. But living some miles in from the coast is no assurance that you won't feel the
The Cascadia Subduction Zone is the sleeping giant. It's there. It's not going away. With good fortune, it may not do more than hiccup a little in
our entire lifetimes or even in our grandchildren's lifetimes. But for anyone who lives in that part of the world, you have to bear in mind that
sooner or later, it will wake up. It doesn't mean you live in constant fear of it. You just need to acknowledge its existence and accept that it can
do far worse than even the Japan quake did.
And yes, if you live near the coast, you need to know how to get to high ground in a hurry, at any time of the day or night.
That's not fearmongering. That's using the good sense the good Lord gave you.
I hope we never see the day the CSZ lets go. I really do. I don't even live there but by the Lord it's not something I ever want to witness even via
Forgive me if I've said too much.