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Zipingpu Dam May Have Triggered the Sichuan Quake
bfwebster writes "An article in the Telegraph (UK) raises an interesting question: was the massive (7.9) Sichuan earthquake that wracked China last year and left millions homeless caused by ground stresses following the completion of the Zipingpu dam? As the article notes, 'The 511-ft-high Zipingpu dam holds 315 million tonnes of water and lies just 550 yards from the fault line, and three miles from the epicenter, of the Sichuan earthquake. Now scientists in China and the United States believe the weight of water, and the effect of it penetrating into the rock, could have affected the pressure on the fault line underneath, possibly unleashing a chain of ruptures that led to the quake.'" The Sichuan region is earthquake-prone, but has not seen anything as large as the 7.9-magnitude quake for perhaps millions of years. The Chinese government denies any connection between the dam and the earthquake and seems to be actively obstructing the access of scientists who want to investigate. The article concludes, "There is a history of earthquakes triggered by dams, including several caused by the construction of the Hoover Dam in the US, but none of such a magnitude."
Those dam quakes always screwing everything up!
- Your stupidity got you into this mess, why can't it get you out? -Will Rogers
As with all things geological, there are a lot of unknown variables, hence the "could", "might" and other diluting terms.
Engineering is the art of compromise.
Or maybe it could have been, "Have it smaller." I wonder if we'll ever know.
The CB App. What's your 20?
I feel a bad movie based on this where need to blow up dam to stop a super quake from happening is coming.
Chinese officials will conclude that the scientific findings are acurrate and convincing, will acknowledge that the dam did cause the quake, will apologize sincerely, and resign in disgrace. The replacements will then close down the dam, making sure to dismantle it in an ecologically sensible way, doing the least disruption to the surrounding communities as well, and every victim of the quake will be compensated accordingly. You know, much as it would happen here.
You really have to love government humility and responsibility.
This is the country that strictly enforces a one-child-per-family law, and you think the Chinese government actually wants more people to take care of?
Haven't we known for 40 years now that injecting water into a fault can trigger a quake?
I've abandoned my search for truth; now I'm just looking for some useful delusions.
Sir Ranulph Fiennes (the famous arctic explorer, among other things) was actually kicked out of the SAS for destroying a dam using stolen explosives. You can google for more detailed accounts of the story, but here's one:
http://www.independent.co.uk/student/career-planning/getting-job/my-first-job-explorer-sir-ranulph-fiennes-was-an-sas-officer-420601.html
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let's say they know dams cause earthquakes. ok, so there will be some minor earthquakes. but 7.9? no one is going to predict anything that large
still, let's assume the dam is still the trigger for the 7.9 earthquake. emphasis on trigger. its going to happen someday anyway
if they never built the dam, we'd be talking about the 7.9 or 8.3 sichuan earthquake of 2031 or 2102
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
Would a 7.9 quake, although large by earthquake standards, even leave evidence that lasted more than, say, 1000 years? You might be able to tell if you took a cross section of the entire fault line, I suppose, but not all fault lines are known. A L.A. city geologist found a previously unknown (but not currently active) fault under the house of a friend of mine when he was having some drainage work done; new ones are discovered all the time.
09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0
I choose later. Preferrably after I'm dead.
Tell that to your grandchildren.
Don't worry, I'll find a way.
Sincerely, Nature
Every natural disaster has a disproportionate effect on the poor! That's just one of the many, many reasons why it sucks to be poor!
I've abandoned my search for truth; now I'm just looking for some useful delusions.
If this is true, then just wait until the Three Gorges begins to top off (it has been filling for years now and has some time to go.)
This earthquake killed less than 100,000 people.
In 1931, the flooding of a different river (the Yellow river) killed 3.7 millions. And thirty years before that, another flood in China killed 1 million people.
Flooding kills poor people. Dams prevent flooding.
The lil' sob's probably won't hear anyway, what with their loud music, and their hippin an their hoppin, and their bippin and their boppin.
GET OFF MY LAWN!
Hahahaha - Zipping Poo... Best name for a dam ever!
Won't be able to. Remember? Dead.
Sorry folks.
They would have been better off if they hadn't elected the idiot Mayor and Governor.
People like to blame FEMA but FEMA did they typical job. The local and state governments where criminal.
It was the local government that failed to use the school buses to evacuate the people. Heck they even left them in the flood plane. My city has been hit by three storms. The School buses are always moved to stageing areas near shelters. The state government put police out side New Orleans to keep the people IN after the storm.
Heck the state didn't even have shelters for all the people. Texas had to provide shelters.
What really ticks me off is people forget about Mississippi. They took the worst hit for Katrina. They had a HUGE store surge that took out whole sections of their coast line. They had many homes whipped out but you don't see people up in arms because their state and local governments where a lot more effective.
What is the worst part. That idiot moron of a mayor GOT REELECTED!!!!!!!!!!!
See my blog http://ilovecookes.blogspot.com/ for light hearted technical information.
"This earthquake killed a lot of people and ruined the lives of countless others. That effect was disproportionate on the poor."
Chinese poor have always been expendable. They are easily replaced, and their rulers have always understood this.
"This post is an artistic work of fiction and falsehood. Only a fool would take anything posted here as fact."
What is the worst part. That idiot moron of a mayor GOT REELECTED!!!!!!!!!!!
And, bringing it around full circle, electing terrible leadership is a consequence of being poor and uneducated. The people re-electing the mayor bought the line that the federal government was primarily responsible for the mishandling, and probably made a Bush joke or two... not understanding what role the state and federal governments were supposed to play.
The feds should be thanked for cleaning up the mess Louisiana got itself into.
Maybe they can get this drilling crew on the mission to save the day!
All humour aside, most people have no clue about the energy levels and destructive power available to natural forces, just on our world. (ie:water) Even engineers can fall prey to their preconceptions at times, if they are not diligent. Water is a powerful force, in scale.
Most people perceive the Earth as a solid/stable surface to build on(dig to 'bedrock' for the foundation, etc...), frequently forgetting Earth more resembles a poultry egg: relatively thin shell covering/encasing a liquid center...and just as fragile on scale.
At our most terrible destructive level available technologically to humans today, we are still just 'wannabe' punks in the big picture. Actually, I would argue that communication tech is the most powerful weapon/tech we have devised to date.
*(IAANB) I Am A NASA Brat![clarification of subject line]-just could not pass this one up. And NOT trying to pick on engineers, who have demanding job requirements, but there is a good reason to put erasers on pencils! :-)
Sorry if this was more than you bargained for trying to make a 'funny', but you did raise a valid point! :-)
Down With Slashdot BETA!!! I've been around the corner and seen the oliphant; you can only abuse me from your perspecti
Dams don't prevent flooding. They just move it somewhere else.
Right, and we know exactly where that somewhere else is (right behind the dam) and we don't build houses there anymore because it's a lake.
Dams prevent catastrophic, uncontrolled flooding by buffering the surge in a lake and letting it out slowly. The Ohio River no longer floods because of the hundreds of artificial lakes created in its watershed, for instance.
Do you have ESP?
Of course, preventing flooding of flood plains wrecks the ecology and in many cases has resulted in the severe degradation of the arable land downstream.
A more sensible solution would be to not build towns and cities in flood plains. But it's a bit late for that.
"Software is too expensive to build cheaply"
Paleoseismology as you described is actually quite difficult. In the case of the San Andreas, you can't really look at off-set streams and such. You can rarely discern more than one or two events along such offsets, and once you do, it is very difficult to determine the age of the offset. You can get the amount that it's moved, yes, but not the timing. Worse, since you don't know the timing, you don't know if the offset is from one or more events.
The way it's done for strike-slip faults like the San Andreas is to look at a cross-section perpendicular to the fault, looking for layers of material off-set (or suddenly changing thickness, etc.) along the fault. The best way to date those layers is through carbon-14 dating of organic material, which can give you accuracy only within ~1-200 years - and that's assuming that the organic material you date is not from elsewhere, is not from 200 year old trees, etc. If an event offsets every layer from the bottom up to a certain point, you date the top layer that it cuts through to get a maximum age, and the layer that it didn't cut through is the minimum age.
You can imagine the difficulty and ambiguous nature of this. The individual layers that you have to recognize and date are on the scale of centimeters to decimeters - I've seen some of the areas that were used, the famous one being along Pallet Creek which is along the San Andreas northeast of LA (I have a picture of it - well, it is a picture of a girl standing in front of it - here: http://www.flickr.com/photos/penguinchris/3037578910/) Here, luckily there was constant, relatively rapid deposition of material. In most places this is not the case, so any record of movement on the fault is eroded away.
For the San Andreas, we have a partial record going back ~1500 years. There really is no reliable way to reach back further than that - the record isn't normally visible in older rock units. Looking at the larger-scale structures is interesting by itself but doesn't tell you anything about when specifically there was movement. The fault system in the Sichuan region is fairly well understood - it is a kind of combination strike-slip/thrust fault (see http://quake.mit.edu/~changli/wenchuan.html for some nice diagrams.) But I want to call BS on the idea that they have any idea how frequently major earthquakes have happened there - and even if they do, the idea that it is "perhaps millions of years" since the last one is ridiculous no matter what.
And then, when you *do* figure out a approximate year for an earthquake, how do you determine how big it was? Again, extremely difficult! The best estimates come from comparing old written records of destruction with those from modern earthquakes - nothing scientific at all!
What's being done extensively with the San Andreas is physics-based computer modeling - we have some idea of the force building up, and combining that with records of historical earthquakes we can make an estimate of a major earthquake every ~150 years. But even for this, the best-studied earthquake area, it's not much more than a guess.
I don't know as much about the Teton fault (other than that it is a normal fault, not a thrust fault as you stated ;) ) but I'll comment on the idea of a "magnitude 7 earthquake every 400-700 years." These kinds of estimates are based on the very difficult work I described earlier (and I'm not sure how much has been done for the Teton fault) and whatever geologist came up with that would probably admit it is a simple guess without much to base it on. I mean, think of it - is knowing there's a large earthquake every 400-700 years really all that useful anyway?
By the way, I assume any dating of the Teton fault would be done this way: when new patches of rock are exposed along the fault as you described, they start getting hit by cosmogenic radiation. By measuring the amount of cosmogenic radio isoto
Of these muthafuckin' QUAKES on this muthafuckin' (fault)PLANE!!!
"When information is power, privacy is freedom" - Jah-Wren Ryel
>Dams prevent catastrophic, uncontrolled flooding by buffering the surge in a lake and letting it out slowly.
As long as they're big enough. If they're not, a rapidly increasing flood of water, that if left uncontrolled might rise at 2 feet an hour, flooding many houses, could be turned into a 20 foot high wall of water, debris, and rock from washed-out dams that kills 145 people rather than just destroying a bunch of houses.
Every "flood control structure" on that river got ripped out. A flood that had almost the same rainfall 40 years earlier didn't kill anyone because it took two hours to go from heavy runoff to full flood. My friends that were down in the canyon in the 1976 flood said the front wave of the flood was moving at about 60mph and consisted mostly of a mass of mobile homes (with the occupants still in them.)
Nostalgia's not what it used to be.