Nuclear waste loonies in Windsor

I was waiting for this. The federal report on the storage of high-level nuclear waste mentioned everybody and their dog as candidates for a deep waste anti-mine. Now a local desperate candidate has whipped up the conspiracy theory that Windsor, Ontario (low on the list of best places to visit!), has been singled out for nuclear waste.

Of course, nearly any town in Ontario could do this, but Windsor is the first! People should be more concerned about real plans! One day, I would be proud to get money for a decent effort, but I haven't seen it yet. I would also like a decent effort for a new nuclear plant (ditto!). Speaking of which, there must be dozen people in Canada, who could lead a new plant, but they are all very retired. I know there is now an effort to knock at their door, and I hope, for their health, that they have a good chuckle! That only leaves me!! :) (and right now I'm at the cottage, enjoying the fall colours).

US utilities can jump-start

This is interesting to starving geologists and geophysicists, like me! (keep clicking on those ads!). In the US, a ton of lobbyist money was poured into redefining the word 'construction'. Now, construction is defined as 'putting the cherry on top', or pouring concrete for the reactor. All the bulldozing, excavation, drilling, tunneling, etc, can be done, before the first paperwork flies.

This, of course, greatly disappoints the 'loyal opposition', who relied on infinite amounts of courtroom logjams to block any hope of a nuclear plant. From one extreme to another! Should be fun....

ps. Ontario better get its act together and start doing something that resembles intelligent action, on building a new plant!

Fault discovered beneath nuclear waste dump!

No, it isn't up at the Bruce! It's the poor, hard-hit Yucca-yucca site that the US has pinned so much hope on, merely because it's in the middle of all those old nuclear bomb sites.

They have had the difficult task of showing that the area is a perfect glass marble, and will remain pristine for a million years! Well, nothing and nobody is that perfect! I wonder how this will affect all those new nuclear plans....

North Channel DEM's

Here is the North Channel, which is the zone of water north of Manitoulin Island. It has the most fascinating geology, and once the election is over, I might delve into it.


You might notice that something big and nasty zooms into it, which is the whole reason it is there. Here is an angle shot.


Again, just like the Bruce, this is a most unstudied area.

North Channel Nuclear Plant Lives!!

OMG! I just read this. They said the north channel plant was studied in the 70's, but completely forgot that we resurrected it in the 90's for the 'great expansion'. I spent a whole summer there doing the geophysics! We had tons of data, and then were ordered by the NDP to destroy it all!!

Of course, I have it all committed to memory :). I won't tell them what it showed, because that would spoil their happy-happy party. I'd love to go on the north channel in the summer and do it all over again. I'd want a fancier ship, and a pretty crew.....A very suitable boat for marine geophysics.

Meteor funnies

It's a hot September up at the cottage. I'm up with the dog and we went hiking, to do some fishing. Only caught one little one, which I threw back. Hiking is great in the fall, no bugs!

You've got to read this bloggie thingie, it's hilarious! If it is just a giant earth-zit, it will be hard to drain and prove anything. Probably just a mud sinkhole, since I would think that anything which would create that crater would knock down some stone houses.

Fault geology of Hamilton, Ontario

As I have mentioned previously, one really huge fault whips down through Toronto and Hamilton. Now it happens in my many travels and fishing trips, that the most dramatic scenery is associated with earthquakes. If you take the beautiful seacoast road down from San Francisco, you can see these marvelous terraced beaches. Each terrace has been created by a huge M9 earthquake! If we didn't have earthquakes, everything would be ground to a pulp, and be as boring as Toronto!

This fault appears to be most active at Hamilton, and the spectacular topography is a result.

Good old Hamiton is located at the west end of Lake Ontario. It is noted for its stinky steel mills, and less noted for the swamps everywhere. In fact, I was told these swamps are extremely deep, and have blocked decent railroad access for years.

I have been playing around with Digital Elevation Models (DEM's), and viewers. I was using 3DEM to great success. Here a shaded relief view of Hamilton.


That great big gash in the Niagara Escarpment is the Dundas Valley, which was also a major glacial lake drainage outlet, and affects the sediments in Lake Ontario for a great distance. Nobody has really wondered why it is there.

The real fun with 3DEM is taking oblique views. Here's one, shooting down the fault.


Now, don't you wonder about Hamilton? The view would be much more spectacular if we could remove the sediments. Then you would see something! We did a lot of geophysics out in the lake, where you can get an idea of the depths of the swamps.

Why do we even care about Hamilton? First off, the scenery is nice. Second, all those swamps are formed by an active fault, somewhat like sag ponds, but over a much longer time. They are doing a lot of building in those ponds, and I think it is somewhat dangerous.

The next big earthquake in that area will be a high-speed thrust, much like some of the more destructive earthquakes that hit Japan recently. The damage intensity will have a very narrow zone with a high Peak Ground Velocity (PGV). The deep swamps will amplify this ground motion 10 to 100 times. The damage will be incredible! This earthquake will blow out the electricity and natural gas for most of Southern Ontario.

Yet, we merrily go on, ignoring this threat, not doing the slightest little thing to mitigate the disaster. Such is the power of living memory! We remember Hurricane Hazel, because it happened, yet this earthquake has the same general odds of happening. Just hope your house is on solid ground!

Mud volcanos in the news

I just came across this article. Seems that a mud volcano in Trinidad is a tourist attraction!

In the meantime, our fav. mud volcano is reacting to earthquakes. This is always expected, since large volumes squeezing through a little hole, are very efficient indicators of ground strain.

Tsunami dynamics

That series of earthquakes is absolutely fascinating to us 'movers and shakers'. They seem to be rupturing around a large patch that is known to be seismic gap, and has always been expected to rupture in the next 30 years. The articles on this page, basically say that the city of Padang is waiting to die.

The only way that the outer edges of a large zone could be active, is if the zone has begun to move, but it requires a larger critical displacment than the edge zones (see my fault mechanics). It still might take 30 years, or it could happen tomorrow!

We're talking about another M9 here. As explained, the shaking will be average, but the tsunami will be horrendous!

This leads me into tsunami dynamics for people like me (dummies!). I've read a lot about tsunami wave modelling, and the physics of the thing, but I think all the scientists have missed the point! They keep calling this thing a wave, when it's nothing like a wave at all! (at least to the public). This allows everybody to think of this monster as a nicey-nicey surface wave which can be surfed on! (Hey, Dudes!)

I have attempted a drawing showing the real scale of things.


We basically have water, which might be 1000 m deep, spread over a length of thousands of kilometres! My thin blue line should be thinner (try drawing that!), and plastered right onto the crust.

The difference is like walking with a full cup of coffee from Timmy's. You see the little waves, but you can handle it. Now, try filling a cookie tray with water (thought experiment only!), and walking with it. You can always make a few steps, you see the little shimmering waves on the surface, but all of a sudden the water starts to slide, and sloosh! -- bye-bye water!

This is a water slosh that encompasses the full depth of the water. Now, on the figure, the arrow shows where we suddenly pull down on the crust. This is our big subduction earthquake. The water sloshes into the hole, and this starts to propagate over to Padang and Africa (negative slosh). It doesn't take long for the water to slam together, and send out a positive slosh. These slosh pulses involve the whole depth of the ocean, and travel quite slowly, as one would expect.

In one way, the people may be luckier with a big subduction earthquake, because the pull-down causes a leading negative slosh. Thus, when confronted with the ocean disappearing, it behooves one to run like hell to higher ground! Apparently, this might be too late for Padang, they have to start running as soon as they feel the shaking, because the run-up could be kilometres!



Not everybody gets whacked the same. As we can see in this figure, boats out on the cookie sheet don't feel much. To get the full impact, you need a coast geometry that acts like a giant bulldozer, and can scoop up the water from a great depth. A nice gentle slope is the most effective. As we can see, this is no wave, but a giant wall of water slooshing up over your house!

So, forget all those scientists and their talk of 'long period waves'. This is a giant landslide (waterslide?) of water coming right at you!

The marvellous mechanics of the subduction zone

I'm trying out calligraphy with Inkscape. You can add mass, tremor and other neato stuff to mask your normal horrible strokes! I'm still improving, but already I'm better than Brittney in an MTV concert!

Lots of earthquakes lately in subduction zones. I get some questions (none, here, unfortunately), mainly: Why all these earthquakes now? -- Why not? is the correct answer. :) Also, why do these earthquakes have to be so much bigger to get the same shaking destruction as other types of earthquakes. (I made that up myself!)

To answer that question, we have to look at the mechanics, which is slightly different than the other articles I have written. First, I poo-poo the notion that the oceanic crust is pushed down. All oceanic crust eventually gets cold, old, and tired (like me!). It eventually sinks under its own weight, like elephants going to their grave site. Even New York City will (one day) have its own subduction zone!

As show in my great figure, this slab tends to fall at an angle, and rub up against the island arc complex. Mechanically, this slab is really goopy, full of water and sea-shit (see my Carbon Cycle articles), and has different properties than regular earthquake rock. Once in a while, the descending slab gets hung up on the upper rock, and slippery bathtub feet engage (from Fault Mechanics).

All the normal mechanisms for earthquakes now apply, but the dynamic friction drop may (or may not!) be greater because of all the goop. The important thing is that this is an 'upside down' thrust fault, with the moving element being the slab. As such, the rupture, and the high velocity pulse goes downward.

This reduces the impact of the shaking, but things are not so happy for the inhabitants of the ocean shore. The combination of the rapid slip downward, and the attendant push upward on upper crust, makes for some dramatic ocean wave mechanics. It's like suddenly getting up in your bathtub! If we are lucky (like this last one), most of the oceanic energy gets beamed down to the penguins, who can take care of themselves.

As in my beautiful drawing, the oceanic crust eventually gets a nice warm, peaceful death, and the water-carbon gets pooped out at the top, to cause some other problems for the locals....

Of course, the island arc actually gets pushed by all this, and on the other side we get the juicy high-speed thrust earthquakes that cause so much trouble, for their size (as in the Japanese nuclear earthquake).

Geology of Bruce, Ontario

Since the cash has started to fly, I would open up the session by telling what I know about the site. I won't cite references because there aren't any! This is the most unstudied area I know. All information is safely hidden in-house.

I first became aware of the site, when I first joined the big company, 28 years ago. At the time, they were building a water intake tunnel, which was so leaky you had to wear a heavy raincoat to go into it. I was terrified, and never took up the opportunity to visit. To dig that tunnel, they had to use trainloads of grout, and they still ran into a huge cavern. Now there's a dog-leg in the tunnel, in order to go around it.

At the time I was taking stress measurements all over Ontario, and I always found high stresses and solid, tight rock. I could not believe there could be such an area where the rock was so bad, so I made a study of it. I wrote some of the results in Paleocollapse.

As such, I formed a hypothesis, which was testable:

Hypothesis One: The paleocollapse was caused by the dissolution of the deep salt beds under the limestones. There should be standard, solid limestone under the former salt beds.

Over 28 years, I learned a lot, so now there is this:

Hypothesis Two: The salt beds and carbonates were laid on the soft hanging wall of the Grenville Front (megathrust). This eventually resulted in extensive fracturing, and the dissolution of the salts.

Both hypotheses can be tested by drilling a deep hole, which is now being done in-house. I just worry that all the results will be spun towards #1. They have to proceed, no matter what, because they have left no alternative. They hearings will conclude that they should proceed, on the proviso that if they find something politcally unacceptable, they will stop. No scientific criteria will be set.

For interest, look at the Google picture. All of the paleocollapse is below a cliff that runs NE, parallel to the Grenville Front. The area NE of the plant shows the sinkholes, and is exactly like an air photo I once saw that was done before the plant was built.

Deep Geology Thingie dishes out the cash

This article is what I've been waiting for! 100 thousand loonies have been handed out to people, to make the OJ-hearings a bit more exciting. I hope they do a good job!

As we all know, the Deep Geology Waste Respository (DGR, whatever!) is a big plan to spend all that money which has been building up, from the nuclear plants (a percentage is set aside for the garbage). This is generally a good thing, and I'm all for nuclear power, but technocrats are in charge of this money.

These people actually hate to be open, and face the public, so they'll have their lawyers do everything. The people getting the money will have more lawyers. The lawyers will get fancy sports cars. All the money, for and against, will go into the Bruce area, so they'll get new cars, as well.

Will there be any open, and worthwhile science? You can figure this out for yourselves!

Water-carbon III

Wow, I have never gone to 3 parts! I can't even remember where I started!

Ok, I remember. We had 2 dials, the strength of which overwhelms anything that mere humans can do. There really is a third dial, which is a big mystery, and we have no data on it. This is the Solar Input dial, and it can vary by means of changes in the Sun's output, earth wobble, or orbital variations. It works on a much shorter period than the other two, and might be responsible for warm and cold decades, and centuries. For example, nobody knows why the 30's were warmer than now (although everybody knows why were getting warm now!!).

Our two main dials are very slow, and changes take 10's of millions of years. Over the last few billion years, the fossil record shows big swings in both water and carbon.

The variations are caused by our giant plate tectonics machine. When we have an 'average' world (right now!), the oceanic crust subducts under places like Peru. This conveyor belt of junk contains huge amounts of water, and carbonate rocks. Normally, it dives at a fairly steep angle, until it gets deep enough to cook. Then it spews out water and carbon dioxide (along with other nasties), in the big line of volcanoes, right over the cooking zone.

Our recycling factory, however, has not worked at a steady pace over geologic time. Sometimes, the plates move so fast that the cooking process is interrupted, and huge cold slabs of water and carbon get 'frozen' under the continents. This is the time when the 'dials' go down.

Of great interest to me, was the last time when all the continents glumped together a couple of hundred million years ago. When this happened, most subduction stopped, and all the cold slabs were under a giant thermal blanket of fluffy continental rock, and they cooked. Huge amounts of water and carbon were released, and we had the age of the dinosaurs. When the continents broke up again, the cooking stopped, and the world became average again. The poor dinos were not happy when the big lump hit the earth, and did not recover. The mammals started their party!

The final mystery is whether these two dials are independent, or linked together in some manner. It is possible to have subducted slabs that are full of water, and not carbonate, and vice versa. The last big cooking (dinosaurs) had both, but there were really bizarre climate changes in the earlier fossil records. I like to think that they can be twiddled independently, and more science will prove or disprove this hypothesis.

Carbon and Water Cycles II - boring!

Well, I just took my middle guy to Queens. What a zoo moving day is! I didn't like the low-life Queens engineers insulting the parents, they can insult the frosh all they want. Well, they have to compensate for being inferior to UofT Engineering!! :)

Summer is practically over, and it's time for me to look for some tiny bit of work. I sure hope they take their thumbs out and actually start building a nuclear plant! OPG's top guy already bailed, perhaps because he saw all the political (and union!) interference. I like to think that he presented my ideas for a nuclear plant in my lifetime, to the Big Board, and they tossed him out on his ear! :)

Back to our little thought experiment. Like I said, we have two dials on the world, one for water and one for carbon. More water is injected water vapour, and less water means it has been sucked away down deep. More carbon is injected carbon dioxide, and less carbon means that it, too, has been sucked down deep.

The most fun is with the water dial. We can turn it way down and watch what happens. The oceans shrink. There is much less rain in the world. Large mountain ranges continue to rise, but are never eroded, like some ranges in South America. The ice sheets evaporate, but the world gets colder, like when you are camping and it's a clear night, and you know you are going to freeze! Lots of plants die. We have a cold, dry earth, suitable for tiny mammals that live in the desert.

Enough of that, now let's turn it up! We have lots of water, and oceans rise. There is lots of rain everywhere. The mountain ranges rapidly erode, causing carbon-poor sediments. The plants start growing, but become limited by the lack of carbon dioxide, just like my aquarium plants. The earth becomes very warm, because water vapour is the most effective greenhouse gas of all. We have a very wet, warm world, with limited vegetation.

Set the old water back at neutral, and play with the carbon dial! We turn it right down to almost no carbon. The atmospheric carbon dioxide gets quickly used up by plants and erosion, and little sea creatures. The world most likely gets a lot colder (if you believe all those carbon-people!). We have ice sheets, and maybe an ice-age, if the Sun turns down a little, as well. The plants aren't too happy and mostly refuse to grow.

Let's turn it up now. Remember, this dial is infinitely more powerful than the smokestacks of pitiful humans! We flood the place with carbon dioxide, and the oceans go acidic, we dissolve mountains faster, and most likely the world warms up. The plants are limited by the available water.

I think that's generally boring. The big fun comes from twiddling the dials to their extremes. First, we knock down the water, and the carbon. Nothing much happens from the water alone, except the plants are even more dead, and the world is much colder (Iceball Earth!).

Keeping down the water and jacking up the carbon, probably just results in a big mess!

The one I'm more interested in is jacking up the water and the carbon. Then we have a totally different Earth! The mountains are eroded faster, massive carbonate sediments are laid. The earth is very warm, and all the land is filled with swamps, which have tremendous plant growth. The growth of the plants fill the air with oxygen, and the air is thick. All the mammals get fur-rot, and the place fills with dinosaurs. The carbon is so thick, it gets laid down in beds of pure carbon (coal).

These things have actually happened, and we'll look at the geology in the next episode, after I recover from paying the tuition!

Carbon and Water Cycles I - boring!

We have to go way back for this one, before the formation of the earth. Back then we had a real dusty mess, probably caused by some giant star barfing. The Earth, the Sun and the planets started globbing this dirt. The four most common elements swirling around were (in order): hydrogen, helium, oxygen, and carbon. We had lots more heavier elements formed by past stellar explosions.

The Sun and Jupiter sucked up most of the hydrogen and helium, leaving Earth and the rest with the rockier stuff. Lots of carbon fluff bombarded the earth. Eventually the heavier stuff (iron, etc) sunk to the centre of the earth, leaving us with a lot of carbon, oxygen, and hydrogen (in the form of water).

Thus began the great carbon and water cycles. We started with a certain amount of the stuff, but only a variable percentage stays up where we can see it. Over geologic time, there have been great variations.

We now imagine that we are the janitors who take care of the earth (a la that weird movie!). We have two dials, one that controls total available water, and one that controls total available carbon.

(Whoops, old guy has to go to bed!)

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....

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.

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!

Worst geophysics ever

I'm back from the darn cottage weekend. Oh well, I can always say it was a good work weekend, provided I could do things between the rain showers! Thank god for fast-drying outdoor latex paint!

I'm recalling another major project which, although it wasn't an absolute total disaster, it wasn't quite what I expected. We still had money for geophysics, and we were flush from the success of our marine geophysics find. There were some areas on land that the marine surveys didn't cover, so we decided to go for a land seismic (vibroseis) survey. This was in cooperation with several government agencies, so our good 'industrial' money was well amplified.

The details might be buried somewhere in Lithoprobe, but I can't find anything in my papers. We got a survey crew from Alberta with the giant vibroseis trucks (Dancing Elephants). These things are absolutely incredible, and when they start up sending a signal, you feel like you are in an earthquake!

Now, for my favourite blogger, I will explain things in very simple terms. The big trucks have huge hydraulic pads which they place on the ground. They are all linked together, and then they vibrate the pads. Not just up and down, but with a very special little 'song'. Elephants do the same thing with their infrasound.

This song penetrates down into the crust, perhaps up to 30 km deep, down to the Moho (where all crustal structure dissolves). On the way down, the seismic waves start reflecting from layers and bounce back to the top, where they are picked up by a very long string of microphones (geophones). The computers automagically correlate the frequencies of the song, and come up with the depth of the reflector, which is plotted as those ugly reflection plots I showed once.

The nice thing about vibroseis is that we could run the surveys along roads without any trouble (or so we thought....). Turns out that Alberta roads were made for this in the first place, and they have huge compacted shoulders. Our country roads are crap! Also people are a big tetchy about having earthquakes generated near their houses! We were just helping them get ready for the big one!

We had to pay a lot of damages, and I wasn't too happy about the results. Because the roads had a nasty habit of not going exactly straight over the important zones, we had to do a lot of dog-legs which messed up the results. As well, we got perfect reflections off the good rock, but nothing back from the bad rock (where the earthquakes were!). In the end, the results just confirmed what we saw in the marine section, and it wasn't until recently that I figured it all out.

Still, it was a magnificent experience!

Solid as a Rock

I would think that if we are all to be roasted alive by Global Gorming, then the guy would be decent enough to throw in some nice hot cottage summers! Here it is, another cold rainy day in July, and no fishing!

I've always been a rock lover. I guess it comes from the cottage. We have this steep vertical cliff, where the ravens like to have nests, and you can just tell that the rock is anchored down to the Moho. There's something about anchored rock. Most rock isn't truly connected to the earth, even the surface granite. When you put seismometers on it, you can tell that it is delaminated, somewhat detached. True solid rock has a feel to it. If I were to ascribe scientific terms (rather than mystical!), I would think that it has something to do with the general noise field that we can feel with our eyes closed. Solid rock does not echo and resonate with a hollow sound. As well, the rock has thermal conductivity (no gaps) so you can feel that it is cooler with your facial infra-red sensors.

The ancient Incas knew and revered 'true' rock. I was down in Peru, when I saw the most amazing Inca rock wall. Made of pure basalt, it was known to have no mortar, and perfect joints. I felt that I was up against true rock! Those guys knew what they were doing!

I've seen a lot of crap rock! Those of us in rock mechanics wouldn't have a job without it. The most crappy rock I ever saw was up at the Bruce. We put a tunnel through it, and used (literally) trainloads of grout. Even that wasn't enough when we hit a giant cavern! We backed off the tunnel and cut a dogleg to go around it. It's a good thing that water intake tunnel never had to be waterproof!