Friday, August 31, 2007

Opaque Nuclear Plant for Alberta

Don't the facts in this article just reek? An unnamed major customer?? A tiny company nobody has heard of?? If Transparency International ranked this, I think Nigeria would be happy. At least nobody knows anything about the major structural geology there, and the impact of removing megatons of tar sands. The only seismic monitoring in Alta is of the oil kind. :)

More 'scary' global warming positive feedback

Everybody acknowledges that carbon dioxide only takes the tiniest sliver of infra-red radiation, and that there is sufficient amounts now in the atmosphere to make that spectral band completely opaque. In order to make carbon dioxide more relevant, they must invoke 'positive feedback'.

That means the earth is horribly unstable, in terms of CO-2. In other words, a little rise carbon triggers other massive effects. For example, the frozen methane in ocean sediments bursts out. Or ice sheet melting changes the ocean currents. Or there are significant changes in the upper atmosphere.

The latest speculation says that isostatic rebound (crust rising) will trigger massive volcanoes, which will further increase global warming. Of course, if the earth were really that unstable, we might not even be here.

I once listened to a famous professor give a talk on the carbon-water cycle in the past billion years, or so. Atmospheric water is a zillion times more powerful than carbon, but nobody says much on this, other than to invoke more instability (carbon increases water, etc). Anyway, these levels have gone up and down like a toilet seat, over geologic time. Mankind is a mere pimple on a flea, on this timescale. (I think this will be a good boring story!)

I'm not saying anything against all this stuff, since I would probably get a letterbomb or something, but I do find it interesting....

Cradle-to-Grave hits Canada's Uranium

Cottage season is winding up. I'm trying to get in some last-minute staining, but mostly I've got the chainsaw running for firewood. All the dock fishies have fled to deeper water.

Saw this article. Seems there's a push to follow the European model, and have the producers of uranium take back the spent fuel. This seems sensible, but Canada will have to do a better job with nuclear waste, than trying to dig it into the Grenville Front!

You can't really put back the spent fuel in the exact same place you dug it up. Saskatchewan has the most horrible uranium pits, with big tailings dams. Ontario mines extract to the last ounce, which causes horrendous rockbursts. By my studies (hidden in earlier posts), the only place for stable underground disposal is under Southern Ontario, between the mega-thrust faults. Try getting that through politics!

Of course, we could charge a 'disposal tax' for our uranium, and put it into a giant fund, controlled by bureaucrats. Then we know, for sure, that everything will be taken care of....

Sunday, August 26, 2007

Fault mechanisms boring story - II

If you recall, I left you asleep at the point of wonder why we have earthquakes at all in Eastern North America (ENA). Really, if the continent is one big massive piece of tombstone granite, then any stress-relieving earthquake should just carve a 'stress-hole' like boring a mine.

Once this giant Tim Hortons donut gets formed, the remaining rock arches around it, and leaves a perfectly stable structure, with an extinct fault in the middle. This doesn't happen on the plate margins, with all those plates sliding past each other, like those sliding number puzzles we had as kids. For the equivalent, we would need mountain ranges or visible fault sliding to keep the similar ENA earthquake hotspots going for a few million years.

Take a typical fault zone trying to grow up in ENA. It starts with a fractured weak spot, perhaps reactivated by the modern stress field. Eventually (perhaps), the shear stress builds up along a fracture, and the bath-tub feet let go! The fractured rock behaves exactly the same as in California or Peru.

But that's it! Our poor little earthquake has shot its load. The feet have lost their stress, and the surrounding rock has clamped up on our poor little fellow. He can't grow up...

That is, if our earthquake follows conventional thinking for ENA earthquakes. But no, our earthquake fault zone is smarter than that, it is following Harold's original thinking, which doesn't get into the university cartel, because they all got tenure!

Once our earthquake has caused its bump (like a Utah coalmine!), it looks around and sees what it has done, which is to freshly fracture a lot more rock. Its seismic effort hasn't gone into mountain building, or plate sliding, it's gone into fracture surface energy! The academics never thought of that!

But this isn't enough for Quakey (like that name?), in its battle against the implacable rock. Luckily, he's (she's?) under a big hunk of water, and water slowly flows into the new fractures. Now things are cooking! The water does all sorts of wonderful things. First, the water pressure reduces the normal stress on the faults and makes them more likely to slide again. Second, the water hydrofractures and extends existing tension cracks. Finally, the fresh water is corrosive and starts chewing at the adhesion points.

Quakey has become a growing entity, like the Blob that ate New York. So, under Hamilton, New Madrid, countless other ENA locations, we have growing things, which although not actually alive, can give a darn good account of themselves!

As Quakey grows, he can tap into more stress from the surrounding rock, just like we were excavating a new Utah coal mine (or an underground nuclear waste thingie!). He gives many signs of his growth, lots of little earthquakes, just like his bigger plate margin brothers. All the bathtub feet are working, and eventually there is a large, scale-limited earthquake. The process begins again for a bigger earthquake!

Quakey may start as a simple thrust fault along a pre-existing fracture, but soon suffers growing pains. The old fracture provides the water, but a simple thrust fault isn't enough to suck out all the stress from the surround rock. In order to avoid another stress lockup, he must start developing shear wings, which produce strike-slip earthquakes. When he eventually grows into a monster, he resembles the New Madrid fault system.

All the time, these zones are sending the signals to prove Harold is right, and the others are wrong, but the scientists and politicians are too cheap to provide the detailed seismic monitoring that is required. Only the Southern Ontario Seismic Network probably has sufficient horsepower and density, but the Hamilton zone is just a baby!

Everyday, these zones try to show themselves. They send typical 'fluid injection' earthquakes, they mix thrust and strike-slip mechanisms, and they only show up under bodies of water. But without monitoring, the world goes on arguing with Harold....

Montreal crumbles

Well, it's getting to the end of the summer. The water at the cottage has gone back to ice-cold, and the fish have disappeared from the dock. I'm just chainsawing wood for the fire.

Going to Montreal next week. I keep looking up at the decayed bridges, and now I'll have to look for cracks on the road. You wouldn't know that the city is under the sword of high seismic hazard. I really hate to imagine what would happen in an earthquake.

Friday, August 24, 2007

Quakes are like housing prices

Somebody has actually plotted general earthquake activity near Los Angeles, and has concluded that they are currently in a 'lull'. This article.

The only problem is that lulls can be shattered. Or perhaps, they have proven the obvious, that random events cluster, and that 20-20 hindsight doesn't get you anywhere. I suppose one could think the lull will last another 1000 years, and also that housing prices will rise forever.

Ah, such are the dreams of the happy people...

Thursday, August 23, 2007

Pigeons destroying US bridges!

No, it's not the fact they haven't hiked their gas tax in 30 years, it's the pigeons!

Right now they are thinking of better ways to deal with those dasterdly birds. That reminds me that there is the most beautiful Pereguine Falcon nest at Young's Point, Ontario. They built a platform on top of the highest power pole, and there are cute little birdies! Betcha they take care of the pesty pigeons!

Wednesday, August 22, 2007

OPG's Gregory Smith Suddenly Retires

The sleepy media hasn't got hold of this yet, but this is BIG news! Internally, he was known as "The Gregory". He was our Napoleon and General Patton. I was terrified of him, but I thought he was the only one that could lead for the new nuclear plant. He certainly was a darling of the press!

So, welcome to the club, Gregory Smith. With you gone, there is nothing standing in the way of the political technocrats wanting to appear to do something, and spending the big bucks, without actually taking the risk of building something. No new nuclear plants in my lifetime, I'm afraid.

Tuesday, August 21, 2007

Fault stress boring story

We've seen that some very simple physical concepts lead to big earthquakes: dynamic friction, and fractal self-similarity. Finally, we have to deal with the fact that those darn earthquakes keep happening at the same spots, over and over again.

When you slip in the bathtub, you go head-over-heels and dent your posterior. It's over and done with. You don't get up and do it again! We can say that all the energy has been dissipated, the stresses relieved, and this particular mechanism (of laughter for others!) is dead.

But, along all the great faults in the world, those feet just keep slipping, and along the same lines. We have continuing fault mechanics. Most people just take this for granted without looking into the actual beauty of it.

An earthquake always starts with stressed rock. This activates the shear stress on the feet, that is resisted by static friction. People sometimes think that those feet act on their own and cause the big ruckus, but they don't. The entire mass of rock surrounding the feet can be thought of as a giant spring, compressed and fixed at distant points.

If we just cut all the rock around the fault with a giant rigid cookie cutter, then we have an isolated system. Somebody tickles the feet, and they let go. Big earthquake that knocks down stone houses! But something has happened to our system: it's out of gas, and can't generate another fun earthquake. The fault is locked up and extinct, and the people can build more stone houses with impunity.

Nobody really thinks of this on the plate margins, because the plates move, and soon our system is charged up again. If the feet have moved many times in the past million years, they have buffed up a nice bathtub, and the action always happens at the same spots. It's rare that things move to a new bathtub (it's happening in California!).

And now for something completely different! In Ontario (which nobody cares about!) we have mostly rigid rock, which acts as the giant stiff cookie-cutter frames of our previous thought experiment. One would think if we had an earthquake, all the stress would be relieved, and it would never happen again at the same spot. In fact, this is the religion amongst all our emergency measures organizations! :)

The harsh fact is that our earthquakes happen at the same spots again and again, and have done so for millions of years. Many scientists have been baffled by the lack of giant mountain ranges at these locations, since all that seismic energy has to be going into building something! If you look at all seismic hotspots of Eastern North America (ENA), you will see the same boring thing: flat lowlands with lots of water. If you go down to the New Madrid location (hottest of hot spots!), you have to place your head on the ground to see what they call a 'ridge'.

Good night, and we'll continue with ENA mechanisms another time (maybe it'll be on TV! ha, ha!).

Geology on TV

For those who like to watch high-def tv, there is a new geology series coming out on CBC. It starts with Ontario and Georgian Bay, and the billion-year goings-on of that area. Nick Eyles was the main consultant, and I hope this glacial-guy boned up on Precambrian geology!

I won't watch it, because if they miss my mega-thrusts right under nuclear plants, I'll just die! I read the summary, and it looks like they are going after all the cutesy geology for the camera, and missing the boring (but important!) stuff.

Monday, August 20, 2007

Earthquakes move faster than thought

This article is one of many on this interesting topic. I was interested, since I'm quite up on my x-men, and I know that thought-waves travel faster than light! To have earthquakes zipping around the world at that speed, is quite a scary thing!

Of course, the headline writers belong to a different union than the authors, plus, everybody steals from the original article. It turns out to be a rather mundane study, that shows fault propagation faster than a slow S-wave.

This is just basic physics. As mentioned in the boring stories, when a fault is all primed to go, it just takes a little slip to shear the adhesion points, and change the state to dynamic friction. Most faults are not like your feet in the bathtub, in that they are very rough, so it takes a good hunk of displacement to fly. This is generally called the critical displacement (d-c). (Imagine a subscript!).

When all the little feet are primed, ready to slip, we can see that a fault rupture activates seismic waves which supply the critical displacement. If the fault is rough, and the value of d-c is high, then only an S-wave has enough oomph to knock it into action. The fault rupture moves along at a pokey 2 km/s. The faster P-waves just go flying by.

If, however, we have a smooth bathtub-fault, then d-c becomes vanishingly small. This is what I think happens with those fabulously destructive blind thrust earthquakes. Then, the leading P-wave has enough displacement to trigger the slip. When this happens, the leading wave becomes a giant fist, ready to smash any little stone building (or nuclear power plant) in its way. I think our favourite Japanese n-plant got hit with this.

Anyway, the study claims to have measured this on a strike-slip fault, which is rare, but much easier to measure, since you've got seismometers along the length. It will never be easily measured on the thrust faults.

Thursday, August 16, 2007

My fault: boring story part 2

Earthquakes remain boring to us, who live in a fool's paradise. Those, who have recently been whacked, have other worries.

We saw how the crystal grains are little feet on the bathtub, but how does this work up to Peruvian scale? Think of a giant pile of sand, housed in one of those roadside giant boob-huts (is this just an Ontario inside joke?). You are hanging on the rafters, watching a stream of sand fall on the pile. As you watch, you see a pattern of little slides and shifts, and sometimes a bigger slide. The sand is at its angle of repose.

Now, you lower yourself upside down, using your spidey web, with the sand stream reducing as you get closer. As you focus your spidey-vision on the sand, you still see the same pattern of many little slides, and larger ones. In fact, by just looking at the pattern, you can't tell how far away you are, from the sand.

You get closer and closer to the sand. At this time, you switch on the incredible shrinking ray, so you get tinier. Still, the pattern remains the same. Finally, when the sand grains start to look like giant boulders, the pattern breaks, but each boulder is following some simple laws of physics.

In fact, we like to model little blocks because it's fun! And it has some lessons for us, mainly that a tiny movement in one place can trigger a larger movement quite far away.

But back to the pile of sand. We see that the pattern of sand failures is self-similar on all scales, but with a big BUT! That is, the self-similarity only holds between two size scales: that of the whole sand pile, and the size of the individual sand grain.

The concept of two limiting scales really screws up a lot of earthquake people, but I suppose they'll figure it out one day. :) We aren't too sure what the largest scale is (somewhere around a few thousand km), but we do know it varies for each earthquake mechanism. What I find amazing is how small the scale can get. We find that rock bursts in mines behave almost exactly the same as earthquakes, and that rock in a testing machine also shows classical earthquake behaviour to the grain scale. So, I'm fairly confident to state that power law (self similarity) holds from the micro to the mega earthquakes.

So if the entire side of Peru is one big foot in the bathtub, it is composed of smaller feet, which are in turn compose of even smaller feet, down to the tiniest grain. At various times, each foot slips on the bathtub. If you are carefully monitoring the feet with seismometers, you see lots of little slips setting up for a bigger foot. In fact, very roughly, you need about 10 little feet to completely slip, for a foot ten times bigger.

After millions of slips, the biggest one decides to go. It is your biggest foot that does most of the damage, and uplifts the mountains. Those little guys are just a necessary side-show. Is the M8 earthquake in Peru the biggest foot? Most likely not, since that area is know for M9's.

In Ontario, what is our biggest foot? It's probably the dimension of the Hamilton Fault zone, which might be around M6.5. When will that foot drop? The next boring story will concentrate on the need for a continuous operating mechanism to keep the feet slipping.

Harold nearly killed by truck tire!

It actually zipped across the median 100 m behind me, but combined with the tire that zoomed 100 m in front of me, a while ago, this makes an average right through my windshield! Of course, in both incidents there were people who got within a metre, but if they don't want to whine, then it's nothing to do with me!

It's now my opinion that we are once again approaching power law, on truck tires in Ontario. The trucks are getting seedier and seedier. If you can figure out a way to plot the degree of near-miss against frequency, you would get a straight line (log plot). Probably, nobody is keeping track of this, so will 'suddenly' get a cluster of people getting killed 'out of the blue'. Then, once again the Ministry starts crying, waving their arms, and cracking down on trucks.

It's a bit like the earthquake in Peru. I'm reading Darwin's Voyage of the Beagle and I'm coming to his description of his earthquake, which seems exactly like this one. Everybody still builds out of adobe, in a country that can afford concrete domes. Lots of people killed, once again.

Sunday, August 12, 2007

Fault rupture boring story

It's fun on the dock, fishing. All my intellectual energy is totally drained from me, especially if I'm cut off from civilization for a long time. I'm back for a couple of days, and thought it's time for another boring story. This one is about fault mechanics, which I think is the most misunderstood subject of all time (it helps to have a rock mechanics background!).

The whole reason we have earthquakes is because of a simple little physical phenomenon that we observe when we have a shower in a cheap hotel, while forgetting to put in the rubber bathmat.

One minute our feet are firmly on the tub, stuck like glue. The next second, we do one little thing, and swoosh! If we are lucky, the clingy plastic shower curtain has saved us.

This is the most dramatic demonstration that I know, showing the difference between static and dynamic friction. I've done some more details in Fault Friction.

Wet, fractured rock behaves almost the same throughout the world, and this is the stuff of earthquakes! Without a difference, in wet rock, between static and dynamic friction, we would be without most earthquakes (those extremely deep earthquakes are a bizarre exception, but who cares about them?)

So all earthquakes start with a single crystal (grain) of rock (mineral), rubbing against another. There is shear stress, which is a force trying to slide the grains past each other, and there is the normal stress, which is the force jamming them together. At the very tiny point of contact, the minerals (quartz, most likely), are cold-welded, making a very strong adhesion bond.

The shear stress attempts to break these bonds, by inducing tiny molecular earthquakes. Studies show that if we bake these things so that there is no water, then new bonds are formed as quickly as old ones are broken. Thus, the resistance to slipping remains a constant value.

Thus, good old water is need for some action! If we sprinkle in some water, then two very interesting things happen. Firstly, we do not have stability at the near-failure point, because the water acts to eat away at the adhesion points. This little thing, called stress corrosion, is one of the best, totally unappreciated discoveries from the giant money-sucking pit, called the AECL Underground Research Laboratory (URL) (RIP). (Thanktheloard for massive gov't pork!)

Secondly, once the adhesion bonds start to break, they are covered in little water molecules, just like the other potential contact points. When a new adhesion contact wants to form, there's that nasty water gunking things up!

So now it takes some time to form some new bonds, time that the slippery feet (or mineral grains) don't have if there is a big following force (like gravity, or the San Andreas!). The sliding surface starts to zoom, and we have dynamic friction.

As you fall asleep, you may wonder what bathtub feet, and mineral grains have to do with a big old fault. The answer lies in self-similarity and Power Law. Much like a ratty old US bridge, everything can be represented as tiny little feet slipping, over and over again, combining into larger and larger feet, until the whole shebang blows! But those details are in the next boring story!

Thursday, August 2, 2007

Claptrap bridge buys the farm

I can't believe that bridge! Twin towers all over again. One local failure propagates in both directions to take the entire bridge, just like an earthquake! Good thing that old steel yields and stretches so much, so that the deck was let down gently enough to save lives. I'll bet they had a lot of little earthquakes, before this M8! I'll bet the bridge janitors will say it will never happen again! They should get together with the Japanese. Oh well, and I thought nothing ever happens when I'm on vacation.

Wednesday, August 1, 2007

Back for a day

Back from the cottage for major shopping and clearing up the beer bottles from the boys' parties. Absolutely nothing in the news, which is good for a lazy summer, and man, is it hot!!

Just finished the Potter book: they all die! Hope everyone is enjoying this great weather.