Port Angeles council told of casualties, destruction of a massive quake

A M9+ in the Cascadian Seismic Zone is a practical certitude. The only real question is when.

I figured with all of the doom porn going around lately, I may as well trot some* out too:

“This is the first time in 10 years — and I’ve been working on this 10 years — that I have come out in front of a bunch of people and said what we think the casualty levels are going to be,” Buck told the City Council, department heads and about 40 audience members during a two-hour briefing on emergency preparedness.

“And the National Guard supports the numbers.”

The six-week casualty projections for Clallam County break down as follows:

• 800 to 3,000 dead from the earthquake — structural and debris strikes.

• 1,000 to 5,000 dead from the 30- to 40-foot tsunami that would inundate low-lying areas.

• 2,700 to 5,500 dead from entrapment and isolation.

• 200 to 4,000 dead among the fragile population and those with special needs like supplemental oxygen.

• 1,400 to 6,500 dead from a lack of food or water or from exposure to the elements.

That's between 6,100 and 24,000 people.

In one county.

Exactly when the earthquake strikes — and experts say it is not a matter of if, but when — will go a long way to determine the final death toll, Buck added.

The last major earthquake on the 800-mile long Cascadia subduction zone off the Northwest coast occurred on Jan. 26, 1700, scientists say.

Geologists believe there is a 10 percent chance that another 9.0 earthquake will happen in the next 50 years, Orr said.

“If we have an event, it could affect 7 million people,” Orr said of the regional impacts of a megathrust earthquake.

We know it will happen, the evidence is there of it having happened before.

More than once.

The shaking will be incredibly ruinous.

A large section of Port Angeles — the entire area east of C Street and north of Eighth Street — is expected to experience moderate soil liquefaction in the earthquake, according to Buck’s slides.

The downtown core, which was built on fill, will experience severe liquefaction and the tsunami, Buck said.

“You can expect anything that’s built there to collapse, either through foundation failure, piling failures or just flat liquefaction,” Buck told the council.

"Severe liquefaction and the tsunami."

As we saw in Japan, it's not just the shaking of the earth and resultant seismic energy release. There is also the tsunami that accompanies the megathrust earthquake.

“Seventy minutes later, the tsunami — and we think it will be in the 30- to 40-foot range — will come in and it will destroy anything that’s not already destroyed.”

Peninsula Daily News


Some recently published papers:

We present a 3-D model of upper mantle seismic discontinuity structure below Cascadia using a receiver function Kirchhoff migration method. A careful analysis of the primary and multiple reverberated phases allows imaging of the Juan de Fuca plate dipping below the North American continent.

Cascadia subduction slab heterogeneity revealed by three-dimensional receiver function Kirchhoff migration

This article presents a seismic performance evaluation framework for reinforced concrete (RC) buildings, comprising shear walls and gravity frames. The evaluation is undertaken within a performance-based earthquake engineering framework by considering regional seismicity and site-specific ground motion selection.

Energy-Based Seismic Risk Evaluation of Tall Reinforced Concrete Building in Vancouver, BC, Canada, under Mw9 Megathrust Subduction Earthquakes and Aftershocks

The outer coast of Washington State is exposed to significant seismic and tsunami hazard. A Cascadia Subduction Zone (CSZ) event is expected to cause high earthquake intensities and tsunami inundation resulting in considerable infrastructure loss, inundation of developed land, and degraded functioning of coastal communities. One area of particular concern is Pacific County, located in southwest Washington, where over 85% of the population is expected to experience severe shaking intensities. This paper establishes the pre-disaster passenger and freight transportation patterns and the damaged post disaster road network in Pacific County.

THE EFFECT OF TSUNAMI DAMAGE ON PASSENGER AND FORESTRY TRANSPORTATION IN PACIFIC COUNTY WASHINGTON

Related ATS threads:

Quake Watch 2017

A Serious Discussion On The Cascadia Subduction Zone and Latest Studies

*No actual doom porn was used in the making of this thread.

WHERE will HOLLYWOOD GO!
the rest I 'm not related to are on their own...

originally posted by: cavtrooper7
WHERE will HOLLYWOOD GO!
the rest I 'm not related to are on their own...

Port Angeles is in Washington dude...

Hollywood will still be the same asinine place it is...unfortunately.

a reply to: jadedANDcynical

Important thread

My folks moved to Oregon a number of years ago. My Dad took the helm at the power company in central Oregon, and when he asked them about their response and preparedness for a Juan de fuca super slip, they looked at him like he was a nutter.

The company went as far as to interview native american locals. A group they interviewed near the coast said that many natives drowned from the 1700 tsunami, while inside cliff side dwellings that were quite high up.

Needless to say, that company now has many protocol set in place in the event of this disaster, and as you say, when, not if.


A 9.0+ could also trigger one or more volcanoes in the Cascade region. It is probably going to happen before 2100, and it is likely going to be very, very catastrophic.

I pray for everyone during that time.

a reply to: CreationBro

The company went as far as to interview native american locals. A group they interviewed near the coast said that many natives drowned from the 1700 tsunami, while inside cliff side dwellings that were quite high up.

Wow, I had never heard this; thank you for sharing that!

Here's something similar due to the same event:

Recent investigations at the mouth of Seaside Creek in Mendocino County revealed over six centuries of marine inundation events interspersed with cultural use. The well-stratified sequence at CA-MEN-1818/H reflects resource collection visits that began around A.D. 1400 and were interrupted by a noteworthy depositional event possibly linked to a tsunami emanating from the A.D. 1700 Cascadia temblor. Use by Native Americans during the operation of the Mendocino Reservation and intensive occupation by a family of mixed Wiyot and settler descent after A.D. 1900 also were affected by other tidal surges.

Tsunamis, Sea Level Rise, and Cultural Adaptation at Seaside in Northern California

J&C, we all know it's coming sooner or later.

Maybe these statistics will get people on the west coast to wake up to the reality of the situation.

But you and I both know, it will go ignored, and they will carry on in blissful ignorance.

Thank you for sharing this info, I know I will never relocate there.

Safe here in the hills of Kentucky.

Oh yes, when this big one arrives…

a reply to: jadedANDcynical

It'S a frightening reality many coastal areas face here, namely mores the several built up from the water that were filled in by saw dust...Aberdeen and Seattle.

Port Angeles has old underground streets that were built up to the current elevation. So does Seattle. Port Angeles, closer to incoming tsunami waters,of course is where the explained mass causalities will happen in that lower downtown section.

Even if you are on a higher elevation location there's still the risk of liquification.

a reply to: BestinShow

I got ALL exited too...

I'm really glad they released this information to the public.

It allows everyone to plan realistically.

When the quake happens, all aid and rescue will be focused on Puget Sound.

Portland, Ore. might get some aid, but the focus will be on the most densely populated area of the PNW.

Survivors will need to over prepare and expect no help for a long time.

I once read a book that went into detail about the danger in California and the development of the land which magnified the risk. Even though I grew up in California, right on the Whittier fault, I found it so depressing I threw it away before finishing it.

This WILL happen. Now that I am out and no longer used to living with that sword of Democles over my head, I could never move back.

On the other hand, I live now in a place where it isn't expected, houses are made of stone, the nearby nuclear plant is not made to withstand anything over a 4.0 I believe.... if we were to have an earthquake here (even one considered minor to Californians) there would devestation.

Life is risky in general.

Well, it looks like Washington not only has to worry about the possible subduction earthquake off of the coast it also has to worry about top plate earthquakes:

The study examined the Lake Creek-Boundary Creek and Sadie Creek faults along the north flank of the Olympic Mountains, and concludes that there were three to five large, surface-rupturing earthquakes along the faults within the last 13,000 years.

When it says large, it means M6-M7 size events.

...one occurring around 2900 years ago and one occurring 1300 years ago, were likely of magnitude 7 and magnitude 6 to 7, respectively.

A surface rupture of M6-M7 magnitude would cause a lot of damage due to the shallowness of the quake.

As we saw in Mexico with the recent M8.1 followed by the shallower M7.1, if the Cascadian M9+ manifests, it is highly likely that an answering M6+ event will occur in the region mentioned above.

Study Confirms Large Earthquakes along Olympic Mountain Faults

originally posted by: SeekingDepth
Oh yes, when this big one arrives…

My house is right in front of the little yellow dot where it all starts.
Does anyone want to give me money so I can move?

a reply to: SeaWorthy


Id love to give you some but it looks like you ars seaworthy

The reality is that in some of those communities no amount of disaster planning will see them through. It's just the nature of where they place themselves.

I'm of the opinion that the tsunami could be much higher than 30-40 feet, change that to meters and it might be closer. There was an article I used to be able to find about about a 1700's earthquake in which the water from the tsunami made it to the stairs of a church that was 300 ft. above sea level, I believe it was somewhere in what later became California.

a reply to: BestinShow

Oh good grief! I'm going through there next month on my way to Neah Bay...waaaaaaaaay back-whenever I actually graduated from high school there...there had been a small AF Radar station located there, and as was with my dad's luck and the AF's sense of humor, we always managed to get plum "remote" assignments...aaaaannd Neah Bay was it! I've described it to my sons many times over the years and always wanted to take them on a "grand tour". Heck, WHO couldn't resist the allure of a small village with yards chocked full of rusty, old wrecked cars?! After showing them around, I'll be able to look them in the eye and ask how dare they EVER have complained about their high school! For the first, and probably LAST time Mom will have the ABSOLUTE LAST WORD!

My question...since I really don't quite understand all the nuances of quakes, you reckon it'll be safe for us up there?! I mean from any possible random quakes, not the natives? I actually remember feeling the Great Alaskan earthquake when it happened back in...uh, oh well...a while back ago. That's the truth too. Since there wasn't much to do up there we spent spare time, of which there was A LOT, out beach combing and was always afraid of what might wash up on shore. Noting more than and errant mattress and a bunch of garbage ever found its way to the beaches. One time though, my mom found something with USS Arizona inscribed on it...she left it and it was gone when she went to try and find it a few days later.

It's probably a silly arse question, but what the heck...I might be surprised! Thanks!

a reply to: jadedANDcynical

A m9+ will be felt all over the U.S. and around the world. Not to mention it could cause a volcanic eruption at Mt Rainier, and just hope it doesn't cause Yellowstone caldera to blow.

The good news is that real estate in WA may finally be affordable again after the big one hits, because whoever doesn't die will be scared off.

I realized the day after I posted here that I was going a bit off subject, thinking about earthquakes in general along the western coast, and wasn't really commenting on the specific area of the topic. I apologize.