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Comment Re:Preparation (Score 1) 457

Since the frequency of earthquakes there is relatively low they use lower requirements for building strength.

I am absolutely certain you are mis-remembering, or the popsci distorted the engineering in their efforts to make it interesting for public consumption. I attend a lot of disaster conferences. I sat in on a policy session at the rock mechanics conference in Vancouver in the fall of 2007? 2008? where at least 100 global experts gathered specifically to discuss earthquake building codes in subduction zones (including the PNW and Japan). Low-frequency, low-intensity earthquake zones have lax codes, yes, but low-frequency high-intensity zones currently have very, very strong codes that at this point are only revised upwards to be more strong. (The iconic image of the Japanese low-rises toppling over prompted a set of revisions for building on sediment.)

...topple almost every building within a hundred miles of the epicenter.

Again, not a chance that's an accurate geotechnical assessment of any urban center in Canada or the United States. In part this is because our assessments have more to do with the hypocenter (the actual location of rupture) than the epicenter (the surface projection of the hypocenter). In California, the two are often close-enough to being the same, but in subduction zones the depth of the hypocenter has a huge impact on the type of shaking that will be felt. As I've explained in other comments in this thread, the PNW can get shallower magnitude 7 earthquakes that will cause a devastating amount of surface shaking in a very small area, or deeper magnitude 9 earthquakes that will cause less severe surface shaking over a very wide area. It is geologically not possible to have severe surface shaking over a large region*.

* This is true globally, unless you have local superficial geology that intensifies shaking. Mexico City is located in a sediment-filled basin that amplifies ANY surface waves that go anywhere nearby.

Comment Re:Well, as long as we're talking catastrophe (Score 2, Informative) 457

The Yellowstone Caldera is not related to the subduction melt. Mount Saint Helens, Mount Rainier, and the rest of that volcanic chain are related, but plates shifting about in an earthquake doesn't increase or decrease rates of melting.

A bit off topic, but a fun bit of trivia: oceanic plates produce non-violent volcanoes (like Hawaii), continental plates produce highly violent volcanoes (like Yellowstone, although most are very very very small), and ocean melt passing through continental plate produce intermediate volcanoes (like Mount Saint Helens) which are technically less violent than purely andesitic volcanoes, but have larger volumes of magma so are the most destructive. (For the chemistry nerds, it has to do with percent-silica & trapped gas).

Comment Re:And... (Score 2, Informative) 457

A few factual corrections, although I agree with the tone.

The earthquake building code for the United States is the same throughout the country, but it zones the country by expected earthquake risk. California is in a high-risk zone, but so are several other locations in the country. BC, California, and Japan all have fairly comparable building codes. So yes, California's code is very, very good. But it's not, technically speaking, "the best."

Next, California has relatively small translational earthquakes caused by the plates rubbing past each other. This leads to intensely focused, fairly shallow earthquakes, similar to that experienced by Haiti. It's common for one city to be hit hard (LA during the Northridge Quake, SF in '89...) and the surrounding region to be pretty much unaffected.

The Pacific North West and Chile have subduction earthquakes, also called megaquakes because of their incredible magnitudes. These earthquakes are caused by one plate subducting under another, and lead to deep earthquakes with less-intense shaking felt over a larger area. They are also commonly associated with tsunami-generation because of underwater vertical displacement (Sumatra was another subduction quake).

Geologically, the regions you're comparing have very different causes for earthquakes, very different types of shaking felt at the surface, and different impacts on the rest of the rest of the world.

Comment Re:And... (Score 1) 457

Lots of big differences, from geology to building code to economic resilience. If you're curious, I bet it'll be a hot topic in all the big geo/policy conferences this year (AGU December 2011 in SF will probably have a whole session on it)

1. Geology: Haiti was a shallow, translation earthquake. This means that the surface shaking was intense & prolonged over a focused area (just the city). Chile was a deep, subduction earthquake. This means the shaking was spread over a larger surface area (half the country).
2. Awareness: Haiti's fault was only identified in the past few years. Chile's known it's in earthquake country forever.
3. Building code: Haiti did not have an earthquake building code. Chile's earliest earthquake-safe building practices pre-date the foundation of the country. ...and then continue on into the development, economic resiliency, and so on.

Pretty much the only thing the two events had in common was, "the ground shook," and "it happened in the same year." Nothing else is comparable.

Comment Re:Preparation (Score 1) 457

One of the awesome things about earthquakes is that although we aren't so good at predicting exactly when they'll happen, we are very, very good at predicting where (where stress has built up, usually at the ends of the most recent rupture zone) and what type of shaking will occur.

Earthquake codes are designed to match the intensity and style of shaking not just for earthquakes with local epicenters, but what sorts of shaking they'll experience from elsewhere. The United States and Canadian codes were both revised repeatedly long after the threat of PNW mega-quakes were established. The building codes are very, very good (Japan's are also amazing), and quite well-enforced. Sure, we might have a few undetected defectors, like the high rise in Chile, but pretty much every public building in the entirety of BC that needed to be retrofit has been already.

The parent article is not new news. Not even slightly new news. Not even remotely new news. This news is so old, my parents met, got married, had a few kids, then I was born, grew up, went to a bunch of schools, and became a certified disaster expert since it first became well-known to the disaster-community (& it became well-known to the non-expert residents still before I was born). The only reason it's making the popmedia rounds now is because Haiti and Chile raised awareness of the potential devastation of earthquakes.

Comment Re:Preparation (Score 1) 457

Please see "At risk: earthquakes and tsunamis on the West Coast". You can also see the USGS site on earthquake preparation, including seeing shakemaps for your region given hypothetical megaquakes.

No, your buildings and bridges in Portland would not be destroyed, unless they're in violation of the earthquake code that went active in the 80s (with retrofits required by the 00s).

Yes, you should be prepared to survive on your own for 72 hrs, particularly with respect to food, water, and medications.

Comment Re:And... (Score 5, Informative) 457

The problem is: at 8+ magintude, all plans go to crap...

Actually, no. Vancouver is located near a triple-plate junction, and is susceptible to deep magnitude 9 subduction quakes with minimal surface shaking (akin to Chile), or shallower magnitude 7s with a lot of surface shaking. Locally, a magnitude 7 is a lot more problematic, although a magnitude 9 would put everyone else on the rim on tsunami-watch.

Richmond and the unconsolidated saturated sediments they live on below sea water behind a dyke is pretty much out of luck in prolonged shaking, as the liquefaction means they'll discover they built on oatmeal. The only way to earthquake-proof that is to keep Richmond entirely agricultural.

But for the city proper, it's pretty much set. Vancouver is built on glacier-compressed sediment, and once you've had 2km of ice squishing everything flat, as far as earthquakes are concerned, it's pretty much bedrock. The engineered fill around False Creek/Granville Island/the downtown docks are likely to have more problems (honestly, I'm concerned about those nice, huge cranes toppling under a bit of liquefaction, exactly like waterfront in Haiti), but as far as "places with people" go, the biggest danger should be the shower of broken glass in the city core. Even personal preparedness is fairly high: approximately 2,000 students per year pass the intro to disasters course at UBC; I don't have the numbers but I'd guess at least a few hundred take the equivalent course at SFU.

Vancouver Island protects the mainland from tsunami; the only real tsunami-danger east of the island is locally in the fjords if the earthquake triggers a landslide (likely things will fail; not so likely anything big enough will go in any one place to really cause a threatening seche). As for the west coast of the island, this past year's Chile-warning was a good practice run. The last-mile notification is still bumpy, but getting better.

Victoria (on the south tip of Vancouver Island) worries me more -- the current subduction has buckled the island up by approximately 15m, which is an awful lot to deal with if it all slips at once. This is made more complicated by the large proportion of the elderly (Victoria is a major retirement destination in Canada), who have lowered resiliency in emergencies.

Comment Re:Martian Water (Score 4, Interesting) 97

I share your exasperation with the lack of popsci understanding of Mars' variable temperatures & pressures.

When I used to run planetarium shows for kids, I used to explain the temperature gradient by telling them, "If you stood on Mars, you'd wear sandals and a parka, since your feet would be as warm as a summer day but by the time you reached your head it'd be colder than winter in Antarctica!" which, although on the "tiny lies of oversimplification" side, is true-ish and a vivid enough image that they remembered months later.

Comment Terminiology & Reccommended Reading (Score 3, Informative) 97

I love that "above some critical threshold" is listed like a mysterious or complex thing. It's the angle of repose, the angle that a material naturally sits at when you let it fall from a height and pile up. It might be, if things are very complicated, the angle of repose + cohesion, but then you're back at water-based theories again since water is the easiest way to remove cohesion and trigger failure.

I also really like that the experimenters managed to recreate a sand flow in their lab. Of course they did. The field of prior research involving laboratory sand flows is immense, especially if you start including the ones with tiny glass beads of carefully varied diameters instead of sand. The only problem is thioxtropy -- landslides are renowned for having material that exhibit viscosity inversely proportional to velocity -- which is not easily replicable in small-scale lab settings.

I'm not sure if this is a, "Physicists discover what geologists already knew" moment, or a "Journalists are puzzled by the mundane mysteries of science," or what, exactly, but if you want to learn more about landslides on Mars, check out geotechnical journals starting with Lucchitta 1978 (Bulletin of the Geological Society of America, v89, pg 1601) and work your way forward. As the lunar and Martian landslides discredited an entire set of excess mobility theories, they're very well described and discussed.

Comment Re:Email Ad Agencies - They May Be Intrigued. (Score 1) 351

As far as detecting tsunamis from space, while not what the article poster is suggesting, would be a better use of orbiting lasers - detection of small rise in sea-level over a large area would, presumably, be a phenomena easily spotted from space.

...although more sensible than the article's idea, this one also won't work. The ocean isn't anywhere close to smooth -- follow the links on the difficulties of calibrating satellites from this 2007 article for an intro, then look up info on calculating the geoid -- and tsunamis are very, very small in open ocean.

But that's alright, since the science on predicting where the waves will go and when they'll arrive is incredibly good. The science on how big they'll be when they get there... now, that's an interesting problem worthy of more research & innovation!

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