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Multifault earthquake threat for Seattle region revealed by mass tree mortality

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Re: Multifault earthquake threat for Seattle region revealed by mass tree mortality

#61
post #22

Earlier quoted context omitted.

> Funny, cause I live in the SF Bay Area, where the earthquakes are frequent, but they can never reach the magnitude of what's possible by the Cascadia Subduction Zone. What makes you think a big one ("The Big One") isn't going to hit the Bay Area?

From what I’ve read the faults in the Bay Area can’t really generate above an 8.0, whereas the cascadia zone can produce much larger events (remember a 9.0 is 10x the intensity of 8.0). It has to do with the size and type of the faults.

> remember a 9.0 is 10x the intensity of 8.0

10x the ground movement amplitude — 32x the total energy release, though!

Re: Multifault earthquake threat for Seattle region revealed by mass tree mortality

#62

Cascadia Subduction Zone[1] is why I never considered living in Seattle/Portland once I found out about it. Funny, cause I live in the SF Bay Area, where the earthquakes are frequent, but they can never reach the magnitude of what's possible by the Cascadia Subduction Zone. [1] https://en.wikipedia.org/wiki/Cascadia_subduction_zone

My mom was a Red Cross nurse who worked in the relief effort after the 1964 Good Friday earthquake and tsunami that devastated Anchorage and areas as far south as Crescent City, California. It was magnitude 9.2, the second largest in recorded history. The photos she brought back were quite something. I may still have them somewhere, but in the meantime there are plenty online. LIFE.com has a remarkable collection: ht…

My mom was a schoolgirl in anchorage during the earthquake. We have a picture of my grandma and her trailer being 20 feet down from the rest of the ground. Haven’t digitized it yet.

Re: Multifault earthquake threat for Seattle region revealed by mass tree mortality

#63
post #30

Earlier quoted context omitted.

On the other hand, Seattle is one of the best places in the world to ride out climate change, which is 100% happening, and happening already. It’s all a numbers game.

Do you have a source for this? What is "best" in this context?

This is not something with a "source" or a real academic answer. There are too many variables and long tail events.

Survival in some of the worst case climate change scenarios involves moving away from the equator where crop failure and extreme heat will occur.

It involves having good access to water, and ideally farmland as wars over resources and refugee migration accelerate.

Martial law of some kind would become a normalized thing in population centers as basic resources and commodities become more expensive. Seattle has a large military presence.

Seattle is positioned geographical well for these things. Being farther north alone is a huge benefit. The mountains of the west due to their proximity to the Pacific enable much more temperate climates than other port cities.

Re: Multifault earthquake threat for Seattle region revealed by mass tree mortality

#64
post #52

Earlier quoted context omitted.

I don't think they're saying that. But from what I recall reading, the big one that hits Seattle will exceed the big one that hits the Bay. Seattle's big ones are higher magnitude but less frequent. Iirc it's also likely the 9.0 that hits Seattle won't be in most of our lifetimes. The last really big one was before Europeans arrived.

Rainier will erupt first and the mudslide will wipe out all those houses built on the last mudslide.

Rainier erupting would devastate slot of small communities between it and Tacoma. Like Helen’s blowing it’s glacial too (liquifying into a muddy huge river) but worse since the area around is more populated.

Re: Multifault earthquake threat for Seattle region revealed by mass tree mortality

#65
post #57
post #41

Earlier quoted context omitted.

I'm no expert on the region but aren't people in California forever whining about heat waves and water shortages?

Man, I moved from Seattle to the Bay Area and in the intervening 20 years it sure seems like summers in the PNW have gotten hotter than they are down here.

Longtime Bay Area resident here - I haven't looked at the data, but it seems like this area seems to be getting colder over the past ten years. If so, it's an illustration that we're facing not global warming but climate change.

Re: Multifault earthquake threat for Seattle region revealed by mass tree mortality

#66

Earlier quoted context omitted.

Do you have a source for this? What is "best" in this context?

I don’t have sources readily available but I have looked at several climate change projection models for the US in the past to answer similar questions. There are a handful of locales in the US where the local climate doesn’t change much under most models and parameters. They behave almost like fixed points in a mathematical sense. Some of these fixed points are not anywhere you’d likely want to live, so that might n…

[deleted]

Re: Multifault earthquake threat for Seattle region revealed by mass tree mortality

#67

Earlier quoted context omitted.

According to https://www.sfchronicle.com/projects/2023/bay-area-earthquak... vs https://www.newyorker.com/magazine/2015/07/20/the-really-big... you're looking at two orders of magnitude difference in terms of the estimate of people affected. I'm not sure what led to the difference but that's striking.

That New Yorker article goes viral every few years - it's a well written piece and spins a great yarn, but there's some significant hyperbole and it's sources don't quite back up the claims. Yes, a 9.x will be devastating. No, everything west of i-5 will not be toast.

Good thing I'm 10 miles east from that road of doom, I'm sure I'll be safe ;-).

Re: Multifault earthquake threat for Seattle region revealed by mass tree mortality

#68
post #30

Cascadia Subduction Zone[1] is why I never considered living in Seattle/Portland once I found out about it. Funny, cause I live in the SF Bay Area, where the earthquakes are frequent, but they can never reach the magnitude of what's possible by the Cascadia Subduction Zone. [1] https://en.wikipedia.org/wiki/Cascadia_subduction_zone

On the other hand, Seattle is one of the best places in the world to ride out climate change, which is 100% happening, and happening already. It’s all a numbers game.

People were saying that about Vermont, then last summer they had massive flooding that put cities under several feet of water.

I knew a lot of, frankly over-confident people who moved to New England because the news told them it was good for Climate Change. I think the “experts” know a lot less about Climate Change impacts to weather than they want to admit.

Re: Multifault earthquake threat for Seattle region revealed by mass tree mortality

#69
post #65
post #57

Earlier quoted context omitted.

Man, I moved from Seattle to the Bay Area and in the intervening 20 years it sure seems like summers in the PNW have gotten hotter than they are down here.

Longtime Bay Area resident here - I haven't looked at the data, but it seems like this area seems to be getting colder over the past ten years. If so, it's an illustration that we're facing not global warming but climate change.

No, you're looking at just a few years of data on a certain region.

When the global average temperature rises some places will get cooler from time to time, there are multiple underdamped systems at play.

Re: Multifault earthquake threat for Seattle region revealed by mass tree mortality

#70
post #39
post #33

Earlier quoted context omitted.

The next logical question is what set you off to work your way through his lectures? Was whatever caused that, inspired by this? I don't think it matters or anything but it is an interesting question into virality and where ideas come from.

Well, that's a long a twisty route... I was originally watching videos from a guy who goes hiking further north in BC. From there, I searched for similar videos in WA. From there I saw a couple of videos about the modern history (1800's to today) and settlement of Seattle and the sound. From there I saw one of Nick Z's geology videos which I really liked and have been watching them since.

Thanks for the Nick Z rec. Start the video linked upthread and already loving it. I recently went on a earth formation / geology binge on YT over the last few weeks and this is right up my interests.
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