[ShepherdsDog]

$1:

Just my own estimation but I don't think the damage in the Tsawassen area or near the Van airport will be so bad.

Delta(including the Tswassen), huge swathes of Richmond(including the airport) and Langley will experience serious flooding and soil liquefication. What good will the ferry terminal be if everything around it is a huge salt water marsh and ocean? Point Roberts will be an island.

[Hyack]

BartSimpson BartSimpson:

Just my own estimation but I don't think the damage in the Tsawassen area or near the Van airport will be so bad.

That whole area is built on nothing more than hundreds of thousands of years of Fraser River silt. Everything south of UBC/Point Grey down to Point Roberts will simply cease to exist, it will simply slip into the muck and mire caused by the total liquefaction of the "ground". Whatever isn't swallowed will be inundated when the tsunami hits, and it won't take very much of a tsunami as the whole area is already behind dykes.

[Jabberwalker]

Hyack Hyack:

BartSimpson BartSimpson:

Just my own estimation but I don't think the damage in the Tsawassen area or near the Van airport will be so bad.

That whole area is built on nothing more than hundreds of thousands of years of Fraser River silt. Everything south of UBC/Point Grey down to Point Roberts will simply cease to exist, it will simply slip into the muck and mire caused by the total liquefaction of the "ground". Whatever isn't swallowed will be inundated when the tsunami hits, and it won't take very much of a tsunami as the whole area is already behind dykes.

I have family members who have studied this specific geology. I also used to sail with a woman who was dong her PhD at the time on soil liquefaction. If you put a long, seismic-acoustic wave through the stuff, the teeny, suspended plates that make up the clay silts tend to align themselves vertically and anything built/floating on top sinks into the goo. You don't need a tsunami, just the right frequency of shake.
That big, wet low-to-sea-level lying Fraser delta makes the situation there much worse that what they will experience in say, San Francisco or L.A.

[BartSimpson]

Hyack Hyack:

BartSimpson BartSimpson:

Just my own estimation but I don't think the damage in the Tsawassen area or near the Van airport will be so bad.

That whole area is built on nothing more than hundreds of thousands of years of Fraser River silt. Everything south of UBC/Point Grey down to Point Roberts will simply cease to exist, it will simply slip into the muck and mire caused by the total liquefaction of the "ground". Whatever isn't swallowed will be inundated when the tsunami hits, and it won't take very much of a tsunami as the whole area is already behind dykes.

A quake induced tsunami off of the BC coast would be dramatically diminished and its effects considerably dispersed by the time it reached Tsawassen.

A study from 2005 estimates that a 7m wave at the mouth of Puget Sound would be reduced to 1m or less by the time it made Lion's Bay.

http://www.lionsbay.ca/f/TsunamiProbabi ... udy-05.pdf

Even if it hits at peak high tide it's just going to temporarily swamp some low lying areas at worst. At best it'll knock some boats around at their moorings and we might lose a few of the guys who fish on the jetties and breaks.

Of course, it wouldn't hurt to raise the levees in the area to mitigate potential damage.

[BartSimpson]

Jabberwalker Jabberwalker:

That big, wet low-to-sea-level lying Fraser delta makes the situation there much worse that what they will experience in say, San Francisco or L.A.

Liquefaction is typically a localized impact and not a generalized impact. In San Francisco it was the Marina District in 1989 that suffered the most while other parts of the city were virtually unscathed.

In Los Angeles it's the parts of the region that are built on alluvial soils that would suffer the most.



A funny thing in Los Angeles is that as ground water dries up in certain areas it actually makes the area safer in a quake because the ground is less likely to liquefy.

Orange County, where they have a huge program to recharge ground water aquifers is arguably endangering their county by potentially amplifying damage from a quake.

In the Fraser Delta the same dynamics apply. There will be some places where water will blast out of the ground in a local quake and there will be adjacent areas where the quake will be barely noticed.

In the recent Napa quake here in California we saw the same effect where people in parts of Sacramento observed up to 45 seconds of shaking while other people in town observed none at all. The whole area is underlaid with varying types of alluvial soils and varying amounts of groundwater. It's very similar to the Delta area.

But overall there was no noticeable damage.

If a 9.2 were to hit off of BC then that 7m wave would wreak havoc out on the west coast of the island. But it's going to diminish to around 1m when it gets to the ferry terminal. I don't think it'll cause that much damage.

But liquefaction in the area and amplified shaking might cause localized and severe damage to older buildings and roads in certain places. This will be the bigger source of damage than a tsunami in the Van area.

[Jabberwalker]

Vancouver is soaking wet. California most definitely is not.

[BartSimpson]

Jabberwalker Jabberwalker:

Vancouver is soaking wet. California most definitely is not.

Vancouver has plenty more surface water, sure, but in an earthquake it's the groundwater and soil profile that matters the most.

And the Fraser Delta is going to be in a very bad way in the course of both a localized quake and in the course of dealing with the shockwaves from a major quake off of the BC coast. Like I said, I expect the Tsawassen area to get more damage from shaking than from a tsunami.

[Freakinoldguy]

I guess since we're gonna have a <2meter wave I'll have to change my plans about opening a beachfront resort after the big one.

1:

images.jpg [ 17.34 KiB | Viewed 382 times ]

Now the shaking might be something else so, I guess Cocktails, shaken not stirred will be the specialty.

0:

shake.jpg [ 13.34 KiB | Viewed 430 times ]

[Jabberwalker]

Does anybody remember a Calypso song abut the "Big One" back in the 1960's?

chorus:

"Where can you go
when there's no San Diego?

Better get ready to tie up your boat in Idaho".

[PublicAnimalNo9]

BartSimpson BartSimpson:

Hyack Hyack:

BartSimpson BartSimpson:

Just my own estimation but I don't think the damage in the Tsawassen area or near the Van airport will be so bad.

That whole area is built on nothing more than hundreds of thousands of years of Fraser River silt. Everything south of UBC/Point Grey down to Point Roberts will simply cease to exist, it will simply slip into the muck and mire caused by the total liquefaction of the "ground". Whatever isn't swallowed will be inundated when the tsunami hits, and it won't take very much of a tsunami as the whole area is already behind dykes.

A quake induced tsunami off of the BC coast would be dramatically diminished and its effects considerably dispersed by the time it reached Tsawassen.

A study from 2005 estimates that a 7m wave at the mouth of Puget Sound would be reduced to 1m or less by the time it made Lion's Bay.

http://www.lionsbay.ca/f/TsunamiProbabi ... udy-05.pdf

Even if it hits at peak high tide it's just going to temporarily swamp some low lying areas at worst. At best it'll knock some boats around at their moorings and we might lose a few of the guys who fish on the jetties and breaks.

Of course, it wouldn't hurt to raise the levees in the area to mitigate potential damage.

The real flooding fear for the coastal areas after an earthquake isn't so much a following tsunami. The coast of BC and the American Northwest are under a LOT of pressure from the subduction of the Pacific Plate. When that pressure is finally released, much of that area will drop by about 10 ft leaving it permanently under water.

[BartSimpson]

PublicAnimalNo9 PublicAnimalNo9:

The real flooding fear for the coastal areas after an earthquake isn't so much a following tsunami. The coast of BC and the American Northwest are under a LOT of pressure from the subduction of the Pacific Plate. When that pressure is finally released, much of that area will drop by about 10 ft leaving it permanently under water.

It's going to be the local geography that comes into play when we're looking at potential subsidence. In the 1946 BC quake some areas did, indeed, report three meters of subsidence but other areas reported lateral movement and a few others (like in Victoria) reported minimal but observable rise over mean sea level.

Victoria is in the primary upthrust region of the Cascadia fault zone with Vancouver sitting in the subsidence zone and West Vancouver (and the rest of BC) sitting in the secondary upthrust zone.

With all that in mind, Point Roberts may well end up being an island at the end of all of this, regardless of any tsunami activity.

[Thanos]

Freakinoldguy Freakinoldguy:

I guess since we're gonna have a <2meter wave I'll have to change my plans about opening a beachfront resort after the big one.

1:

images.jpg

Now the shaking might be something else so, I guess Cocktails, shaken not stirred will be the specialty.

0:

shake.jpg

Those hipsters and yuppies that drove all the non-rich out of Tofino will certainly be in for a big surprise one day.

[BartSimpson]

Nope, the clever ones will twist things around so living in an earthquake hazard area becomes fashionable.

[Freakinoldguy]

BartSimpson BartSimpson:

Nope, the clever ones will twist things around so living in an earthquake hazard area becomes fashionable.

Cool.

I'd like to be hip at least once before I die.

[bootlegga]

ShepherdsDog ShepherdsDog:

$1:

but haven't even bothered with Travolta's terrible looking film of the same name

DON'T!! DON'T!!

After watching the trailer, I could see it was a POS - reviews after it opened proved me right.

I've come close to borrowing it from the library a time or two, but reason always prevails!

ShepherdsDog ShepherdsDog:

$1:

That means dumbing it down for the masses so that it has a chance of being profitable.

Looks like GDT has done this. He finally caved with in and is going to make At The Mountains of Madness as a PG movie rather than stay true to the story and risk an R rating......all about studio execs wanting to milk more cash from it.

http://blogs.houstonpress.com/artattack ... rrible.php

Sad but true...