Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Multifault earthquake threat for Seattle region revealed by mass tree mortality

science.org

Post reply on HN
Print view View original

101–110 of 149 posts

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

#101

Post by interloxia »

djmips wrote: post #97
btilly wrote: post #51

Earlier quoted context omitted.

Let's see. The Cascadia quake is 100x as big. I'm at 1/3 the distance from the San Andreas fault. Guess who gets the larger earthquake? Add to that the fact that I grew up in Victoria. All of Vancouver Island is a subduction zone during a Cascadia earthquake. Sadly, that means that a good chunk of what I knew growing up winds up under water. Seattle may fare better, but my home town does not.

Can you back that up with some references? Very curious, I've never heard any claims that Victoria will end up under water in a big Cascadia earthquake.

An Ask an Earth-Scientist answer by Dr. Gerard Fryerm suggests a few meters is possible.

>"Will part of Vancouver Island "break off and sink," or "split in two at Alberni Inlet?" No. In a big earthquake the seafloor offshore from Vancouver Island will be uplifted and the area along the coast will sink, but at worst that sinking will only be a few meters. If you live very close to the beach and close to sea level then there is a possibility that your house will be flooded, but no big piece of the island is going to break off and disappear. It is possible that there will be submarine landslides along the steepest slopes offshore, but each of those is likely only be small in extent.

http://www.soest.hawaii.edu/GG/ASK/vancouver.html

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

#102

Post by TheOtherHobbes »

mnky9800n wrote: post #93
DoreenMichele wrote: post #82

Earlier quoted context omitted.

I can't readily find a source, but there was another one some weeks back of around 4.0. I can't decide if these are good news making a big quake less likely or foreshadowing of a big quake coming.

There is little evidence that earthquakes come as precursors to larger earthquakes. Most papers reporting such things have selection bias since they are written after the big earthquake occurred.

It's more the other way around. A large earthquake is often followed by a swarm of aftershocks, some of which can cause significant damage.

The media failed to report that the recent quake in Morocco was followed by tens of smaller quakes over the next few weeks, all in a small-ish area that had been quake-free. (In recent memory, at least.)

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

#104

Post by 23B1 »

cossatot wrote: post #78

I wasn't involved in this study, but I wrote the study that estimated the magnitude of this earthquake[0]. In case anyone is interested, usually the magnitudes of 'paleoearthquakes' (historic/prehistoric earthquakes discovered by finding evidence of old ground deformation) are estimated by relating the measured offset of the earth's surface or a rock/dirt layer across the fault line to the earthquake magnitude throug…

Thank you for this fascinating comment.

Out of curiosity, do you have any insight as to the Portland, OR area? We always seem to get glossed over in discussions about the PNW and the West Coast in general.

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

#105

Post by 23B1 »

elliotec wrote: post #95
meowkit wrote: post #63

Earlier quoted context omitted.

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…

This all sounds reasonable but also anecdote. I'm curious if there are any analyses, studies, or anything other than PNWers' HN comments backing claims like these.

I doubt it. It's an exercise in predicting the future, with so many variables, over such a long timeline, that any model will just unwind.

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

#106

Post by ghaff »

oceanplexian wrote: post #68
ksenzee wrote: 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.

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.

You do get flooding and at least residual hurricanes in New England. e.g. [1] Depends where your house is of course. Some properties are probably pretty well-situated; others much less so.

Just about a month ago the city next door to me in MA got a freak foot of rain which caused some serious flooding. I had to pump water out of my basement for the first time in years.

Very few places are immune to at least local natural disasters of various types and some of those, like the Vegas area have their own long-term issues.

[1] https://www.weather.gov/media/btv/events/1927Flood.pdf

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

#107

Post by pbhjpbhj »

isoprophlex wrote: post #94

To date these Puget Sound samples with a second, independent method, we analyzed individual tree-ring sequences for a jump in annual radiocarbon concentrations associated with an extreme solar proton event (30, 31). This rapid, large magnitude (~10‰) radiocarbon excursion between the years 774 and 775 CE is recorded globally in tree cellulose and can therefore be used as an exact geochronological anchor point (30, 32…

Can we do the reverse process, find solar proton events from dendrochronology data?

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

#108

Post by rapind »

seanmcdirmid wrote: post #64
rapind wrote: post #52

Earlier quoted context omitted.

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.

Yes and a lot of these suburbs are built upon the mudslides from previous (recent) eruptions (few million people). Last I heard it was a 1 in 7 chance in my lifetime. It's incredibly stupid and dangerous. Mudslides can travel up to 50 mph or more, and it doesn't even need to be an eruption that kicks it off.

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

#109

Post by MiguelVieira »

pbhjpbhj wrote: post #107
isoprophlex wrote: post #94

To date these Puget Sound samples with a second, independent method, we analyzed individual tree-ring sequences for a jump in annual radiocarbon concentrations associated with an extreme solar proton event (30, 31). This rapid, large magnitude (~10‰) radiocarbon excursion between the years 774 and 775 CE is recorded globally in tree cellulose and can therefore be used as an exact geochronological anchor point (30, 32…

Can we do the reverse process, find solar proton events from dendrochronology data?

Yes

https://www.reuters.com/science/huge-ancient-solar-storm-rev...

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

#110

Post by 83 »

mateo- wrote: post #54
tony_cannistra wrote: post #23

A particularly crazy thing I learned from some friends who I know who work in this field is that they use underwater hydraulic chainsaws (!) to sample some of these trees. https://www.stanleyinfrastructure.com/products/underwater-ch... The field work in general seems very wet for this kind of research. (my partner did lots of it for her graduate work)

that 3rd pic could be a black metal album cover

"Deep Cuts"
Post reply on HN