Scientists link deep wells to deadly Spain quake

Oct 21, 2012 by Frank Jordans
In this May 12, 2011 file photo, a police officer inspects damage caused by an earthquake the previous day in Lorca, Spain, Thursday, May 12, 2011. Farmers drilling ever deeper wells over decades to water their crops likely contributed to a deadly earthquake in southern Spain last year, a new study suggests. The findings may add to concerns about the effects of new energy extraction and waste disposal technologies. (AP Photo/Alberto Saiz, File)

Farmers drilling ever deeper wells over decades to water their crops likely contributed to a deadly earthquake in southern Spain last year, a new study suggests. The findings may add to concerns about the effects of new energy extraction and waste disposal technologies.

Nine people died and nearly 300 were injured when an unusually shallow magnitude-5.1 quake hit the town of Lorca on May 11, 2011. It was the country's worst quake in more than 50 years, causing millions of euros in damage to a region with an already fragile economy.

Using , scientists from Canada, Italy and Spain found the quake ruptured a fault running near a basin that had been weakened by 50 years of groundwater extraction in the area.

During this period, the dropped by 250 meters (274 yards) as farmers bored ever deeper wells to help produce the fruit, vegetables and meat that are exported from Lorca to the rest of Europe. In other words, the industry that propped up the local economy in southern Spain may have undermined the very ground on which Lorca is built.

The researchers noted that even without the strain caused by extraction, a quake would likely have occurred at some point.

But the extra stress of pumping vast amounts of water from a nearby aquifer may have been enough to trigger a quake at that particular time and place, said lead researcher Pablo J. Gonzalez of the University of Western Ontario, Canada.

Miguel de las Doblas Lavigne, a geologist with Spain's National Natural Science Museum who has worked on the same theory but was not involved in the study, said the Lorca quake was in the cards.

"This has been going on for years in the Mediterranean areas, all very famous for their agriculture and plastic greenhouses. They are just sucking all the water out of the , drying them out," he told The Associated Press in a telephone interview. "From Lorca to (the regional capital of) Murcia you can find a very depleted water level."

De las Doblas said it was "no coincidence that all the aftershocks were located on the exact position of maximum depletion."

"The reason is clearly related to the farming, it's like a sponge you drain the water from; the weight of the rocks makes the terrain subside and any small variation near a very active fault like the Alhama de Murcia may be the straw that breaks the camel*s back, which is what happened," he said.

He said excess water extraction was common in Spain.

"Everybody digs their own well, they don't care about anything," he said. "I think in Lorca you may find that some 80 percent of wells are illegal."

Lorca town hall environment chief Melchor Morales said the problem dates back to the 1960s when the region opted to step up its agriculture production and when underground water was considered private property. A 1986 law has reduced the amount of well pumping, he said.

Not everyone agreed with the conclusion of the study, which was published online Sunday in Nature Geoscience.

"There have been earthquakes of similar intensity and similar damage caused in the 17th, 18th and 19th centuries when there was no excess water extraction," said Jose Martinez Diez, a professor in geodynamics at Madrid's Complutense University who has also published a paper on the quake.

Still, it isn't the first time that earthquakes have been blamed on human activity, and scientists say the incident points to the need to investigate more closely how such quakes are triggered and how to prevent them.

The biggest man-made quakes are associated with the construction of large dams, which trap massive amounts of water that put heavy pressure on surrounding rock.

The 1967 Koynanagar earthquake in India, which killed more than 150 people, is one such case, said Marco Bohnhoff, a geologist at the German Research Centre for Geosciences in Potsdam who wasn't involved in the Lorca study.

Bohnhoff said smaller man-made quakes can also occur when liquid is pumped into the ground.

A pioneering geothermal power project in the Swiss city of Basel was abandoned in 2009 after it caused a series of earthquakes. Nobody was injured, but the tremors caused by injecting cold water into hot rocks to produce steam resulted in millions of Swiss francs (dollars) damage to buildings.

Earlier this year, a report by the National Research Council in the United States found the controversial practice of hydraulic fracturing to extract natural gas was not a huge source of man-made earthquakes. However, the related practice of shooting large amounts of wastewater from "fracking" or other drilling activities into deep underground storage wells has been linked with some small earthquakes.

In an editorial accompanying the Lorca study, geologist Jean-Philippe Avouac of the California Institute of Technology said it was unclear whether human activity merely induces quakes that would have happened anyway at a later date. He noted that the strength of the quake appeared to have been greater than the stress caused by removing the groundwater.

"The therefore cannot have been caused entirely by water extraction," wrote Avouac. "Instead, it must have built up over several centuries."

Still, pumping out the water may have affected how the stress was released, and similar processes such as fracking or injecting carbon dioxide into the ground—an idea that has been suggested to reduce the greenhouse effect—could theoretically do the same, he said.

Once the process is fully understood, "we might dream of one day being able to tame natural faults with geo-engineering," Avouac said.

Explore further: Tropical Storm Marie forms in Pacific off Mexico

More information: Paper: DOI: 10.1038/ngeo1610

Journal reference: Nature Geoscience search and more info website

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User comments : 12

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ScooterG
1.2 / 5 (19) Oct 21, 2012
Yup, just as I predicted.

Fracking is the next big money-grabbing, economy-destroying, earth-saving bonanza for the enviro-nazi's. They've just about milked climate change for all it's worth, so it's time for something new.

Coming soon to a tax plan near you!
eachus
2.1 / 5 (7) Oct 21, 2012
Some people don't understand simple arithmetic. I'm not talking about the farmers in Spain. (Read up on "the tragedy of the commons," to understand what's going on there.) I'm talking about the reporters here, and other people, who try to tie fracking with earthquakes.

Fracking started out as a secondary recovery technique for oil wells. Primary extraction, you pump (lift) the oil out of the ground. Secondary recovery, you pump water in, often through one set of wells, while the oil floats to the top of the reservoir, where it is pumped out through a second set of wells. Tertiary extraction adds a surfactant (detergent) to better separate the oil and water.

Where does fracking come in? You pump dirty water into a well, then extract the oil plus gas and some water. This makes it easier to extract oil and gas from "tight" rock formations. But the net takeaway is zero. In other words, the volume of material removed from a set of wells matches the amount put in.
ValeriaT
3.3 / 5 (12) Oct 21, 2012
In other words, the volume of material removed from a set of wells matches the amount put in.
Fracking is using the explosives, which do generate seismic waves, ruptures and slides of rocks. These rocks are porous due the stream of water which dissolve it. If you create the explosion in such porous material, it will settle and collapse into more dense state, even if you wouldn't remove any material from it. If addition, the fracking is made in large depths, so it leads to quakes more easily, than common surface drilling, because of higher pressures existing there. We have many evidence of connection of deep drills to earthquakes, from geothermal drills in Switzerland, from fracking attempts in Englands and Pellsylvania.
eachus
3 / 5 (4) Oct 21, 2012
What has made fracking highly cost effective are new drilling techniques that allow the well to start vertically then run horizontally for miles through a particular geological formation. That allows one well to replace dozens or hundreds. Fracking makes that more effective--more hydrocarbons can reach the well, extending the area the well drains.

But also notice that conventional walking beam pumps can't work with horizontal wells. The only way to get the oil and gas out is to replace them with water.

Natural gas is liquid or dissolved in other hydrocarbons at the pressure at the bottom of a well, conventional or horizontal. You can let it flow "naturally" out of the oil and up the well as gas--for some formations. But if the gas is deep enough, and the major fracking plays in Ohio, Pennsylvania, and North Dakota are for the most part that deep, you have to push the gas out.

So again, fracking does not cause earthquakes since one liquid is replaced by another.
QuantumDelta
4.5 / 5 (4) Oct 21, 2012
The paper didn't particularly criticise fracking, just said it had the potential to do the same thing, also, Valeria, you may wish to polish up on your understanding of that piece of industry, eachus explanation is far closer to reality (though not exact, zero just isn't true, it's the ideal outcome in theory, but never ever happens).
Scryer
2.3 / 5 (3) Oct 21, 2012
So if these techniques can cause earthquakes, couldn't the same theory be applied to drilling oil wells?

Oil provides a natural barrier to seismic activity by acting as a cushion for seismic waves, thus drilling for oil not only reduces our protection against seismic activity, it also produces it according to this article.
Argiod
1 / 5 (4) Oct 22, 2012
@Scryer:
Indeed, any sort of drilling that allows us to remove mass from under the ground, is bound to create hollows that are no longer supported by the pressure of whatever we're removing. Sinkholes and earthquakes are an expected result to any reasonably intelligent thought process. When miners dig underground they have to shore up the cavern they create as they go; otherwise they would collapse on the miners. Without shoring, any open space we create by removing mass, is bound to collapse under its own weight. Of course, when you're making massive profits... who cares about the disasters you create... just hire expensive lawyers to 'get you off the hook' with legalese. With so many humans on the Earth, life is cheap...
cantdrive85
1.6 / 5 (7) Oct 22, 2012
There was a CME (coronal mass ejection) and the proton density of the solar wind spiked on May 10th, 2011. 350 earthquakes occurred worldwide over a five day period from the 10th to the 14th, a 40% increase over the daily average of 50 earthquakes worldwide. Probably just a coincidence.
lengould100
not rated yet Oct 23, 2012
=ValeriaT - Fracking is using the explosives, which do generate seismic waves, ruptures and slides of rocks. These rocks are porous due the stream of water which dissolve it.


Just BTW, "fracking" gas wells doesn't involve explosives (except perhaps relatively tiny amounts to open holes at selected locations in the well casing, with some systems). Fracking primarily involves injecting a fluid under very high pressures into selected rock formations to open up cracks sufficient to release trapped gas and liquids so they will flow into the well for production.

Still, any such action must add some liklihood to iniating an earthquake IF the local formations are under pre-existing strain and therefore subject to earthquakes already. Probably would make for more frequent but smaller quake events.
lengould100
not rated yet Oct 24, 2012
If your reference claims that fracking is accomplished by explosives, then it is in error. You use the term yourself, "hydraulic fracturing", meaning fluids under extreme pressure from pumps used to fracture deep underground rock formations.
ScooterG
1 / 5 (3) Oct 24, 2012
Who's to say that hydraulic fracking isn't a benefit? Maybe the stress relief resulting from fracking will actually stabilize the faultlines?
rubberman
1 / 5 (2) Oct 25, 2012
Came back to this one after the verdict....are the well owners getting charged with manslaughter? I mean these guys actually caused the quake! And I must say De Las Doblas is treading on dangerous ground saying that it wasn't surprising...that's one step away from kmowing and not warning anybody....
TO THE GALLOWS!