Earthquakes Triggered by Dams

Sichuan earthquake damages building, 14 May 2008Miniwiki

Earthquakes can be induced by dams. Globally, there are over 100 identified cases of

earthquakes that scientists believe were triggered by reservoirs (seeGupta 2002). The

most serious case may be the 7.9-magnitude Sichuan earthquake in May 2008, which

killed an estimated 80,000 people and has been linked to the construction of

the Zipingpu Dam.

How Do Dams Trigger Earthquakes?

In a paper prepared for the World Commission on Dams, Dr. V. P Jauhari wrote the

following about this phenomenon, known as Reservoir-Induced Seismicity (RIS): "The

most widely accepted explanation of how dams cause earthquakes is related to the extra

water pressure created in the micro-cracks and fissures in the ground under and near a

reservoir. When the pressure of the water in the rocks increases, it acts to lubricate

faults which are already under tectonic strain, but are prevented from slipping by the

friction of the rock surfaces."

Given that every dam site has unique geological characteristics, it is not possible to

accurately predict when and where earthquakes will occur. However, the International

Commission on Large Dams recommends that RIS should be considered for reservoirs

deeper than 100 meters.

What Are Some Characteristics of RIS?

A leading scholar on this topic, Harsh K. Gupta, summarized his findings on RIS

worldwide in 2002:

Depth of the reservoir is the most important factor, but the volume of water also plays a

significant role in triggering earthquakes.

RIS can be immediately noticed during filling periods of reservoirs.

RIS can happen immediately after the filling of a reservoir or after a certain time lag.

Many dams are being built in seismically active regions, including the Himalayas,

Southwest China, Iran, Turkey, and Chile (see map). International Rivers calls for a

moratorium on the construction of high dams in earthquake-prone areas.

http://www.internationalrivers.org/earthquakes-triggered-by-dams

A Faultline Runs Through It: Exposing the Hidden Dangers of Dam-Induced EarthquakesDate: Wednesday, March 11, 2009

Besides posing a major risk to dams, scientists are increasingly certain that earthquakes

can be triggered by the dams themselves. Globally, scientists believe that there are over

100 instances, strewn over six continents, of dam reservoirs inducing earthquakes. The

most serious case could be the magnitude-7.9 Sichuan earthquake in China in May

2008, which some experts believe may have been induced by the Zipingpu Dam.

Download the factsheet for more information on Reservoir-Induced Seismicity, including

key case studies of potential RIS sites, quotes from leading seismologists, and a list of

major RIS cases and hotspots worldwide.

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How Oil and Gas Disposal Wells Can Cause EarthquakesView All Topics »

BACKGROUND

PHOTO BY KUT NEWS

This rig uses hydraulic fracturing to obtain gas from Texas' Barnett Shale formation. Photo courtesy of KUT News.

Does Fracking Cause Earthquakes?Hydraulic fracturing, or “fracking,” (a drilling process that injects millions of gallons of water, sand and chemicals under high pressure into a well, cracking the rock and to release natural gas and oil) has only been known to rarely cause earthquakes.

But the disposal of drilling wastewater used in fracking has now been scientifically linked to earthquakes. The fluids used in fracking (and the wastewater that comes back up the well) is disposed of by injecting it into disposal wells deep underground. This is generally regarded as the safest, most cost-efficient way to get rid of it. But in some parts of the country, especially in the Barnett Shale area around Dallas-Fort Worth, it has also been causing earthquakes. And they’re growing both in number and strength.

How Fracking Disposal Wells Can Cause EarthquakesThe culprit of earthquakes near fracking sites is not believed to be the act of drilling and fracturing the shale itself, but rather the disposal wells. Disposal wells are the final resting place for used drilling fluid. These

waste wells are located  thousands of feet underground , encased in layers of concrete. They usually store the waste from several different wells.There are more than 50,000 disposal wells in Texas servicing more than 216,000 active drilling wells, according the the Railroad Commission. Each well uses about 4.5 million gallons of chemical-laced water, according to hydrolicfracturing.com.

“The model I use is called the air hockey table model,” says Cliff Frohlich, a research scientist at the  Institute for Geophysics   at the University of Texas at Austin. “You have an air hockey table, suppose you tilt it, if there’s no air on, the puck will just sit there. Gravity wants it to move but it doesn’t because there friction [with the table surface].”

But if you turn the air on for the air hockey table, the puck slips.

http://stateimpact.npr.org/texas/tag/earthquake/

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U.S. Maps Pinpoint Earthquakes Linked to Quest for Oil and GasBy RICHARD PÉREZ-PEÑAAPRIL 23, 2015Photo

Sparks, Okla., in 2011. A report says Oklahoma has been hardest hit by human-caused quakes.CreditSue Ogrocki/Associated PressContinue reading the main storyContinue reading the main storyShare This Page

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The United States Geological Survey on Thursday released its first comprehensive assessment of the link between thousands of earthquakes and oil and gas operations, identifying and mapping 17 regions where quakes have occurred.

The report was the agency’s broadest statement yet on a danger that has grown along with the nation’s energy production.

By far the hardest-hit state, the report said, is Oklahoma, where earthquakes are hundreds of times more

common than they were until a few years ago because of the disposal of wastewater left over from extracting fuels and from drilling wells by injecting water into the earth. But the report also mapped parts of eight other states, from Lake Erie to the Rocky Mountains, where that practice has caused quakes, and said most of them were at risk for more significant shaking in the future.

“Oklahoma used to experience one or two earthquakes per year of magnitude 3 or greater, and now they’re experiencing one or two a day,” Mark Petersen, the chief author of the report, said. “Oklahoma now has more earthquakes of that magnitude than California.”

The report came two days after Oklahoma’s state governmentacknowledged for the first time the scientific consensus that wastewater disposal linked to oil and gas drilling was to blame for the huge surge in earthquakes there. The state introduced an interactive map showing quake locations and places where wastewater is injected into the ground, and the state-run Oklahoma Geological Survey said it “considers it very likely” that the practice is causing most of the shaking.

Hydraulic fracturing, a drilling technique that injects a high-pressure mix of water and chemicals into the ground to break rock formations and release gas, has drawn widespread attention. But injecting water to dispose of waste from drilling or production is a far greater contributor to earthquakes. The federal report excluded human activity, like mining, that can cause quakes but does not involve large-scale fluid injection.

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Earthquakes Caused by Human ActivityThe maps below show where there has been seismic activity, caused mostly by oil and gas operations. Northern Oklahoma and southern Kansas have been especially hard hit, with an exponential growth in the number of human-caused earthquakes.

1957 to 201220132014

OHIOOHIO

COLO.COLO.COLO.KAN.KAN.

OKLA.OKLA.OKLA.

N.M.N.M.N.M.ARK.ALA.TEX.TEX.TEX.

Source: United States Geological SurveyContinue reading the main story

RELATED COVERAGE

Oklahoma Recognizes Role of Drilling in Earthquakes APRIL 21, 2015

As Quakes Rattle Oklahoma, Fingers Point to Oil and Gas Industry APRIL 3, 2015

In one of the 17 areas identified in the report, around Colorado’s Rocky Mountain Arsenal, injections of chemical waste set off earthquakes starting in the 1960s. But the vast majority of the quakes since then have involved oil and gas production.

Many scientific reports, published over decades, have said that pumping fluids into the ground at high pressure can set off earthquakes. But until fairly recently, energy companies and regulators in some energy-producing states insisted that the link was still in doubt.

Most affected states have now acknowledged it, but Oklahoma had not until the recent statements by officials there. Still, state regulators around the country have not gone as far in controlling industry practices as environmental groups have asked, and there is little sign that the new federal findings will goad them to go farther.

Matt Skinner, a spokesman for the Oklahoma Corporation Commission, the state’s top regulatory body for oil and gas exploration, said Oklahoma already required a “seismicity review” for proposed wells. “Any tool we can use in response to triggered seismicity,” he said of the new report, “would be important to us.”

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Asked about the report, Lawrence E. Bengal, director of the Arkansas Oil and Gas Commission, also pointed to what his state had already done, after a surge in earthquakes north of Little Rock in 2010 that made the state second only to Oklahoma in induced quakes.

The commission imposed a moratorium “prohibiting the drilling of any new disposal wells in the area where the earthquake activity had occurred,” Mr. Bengal said, ordered the four active wells in the area plugged and

ruled that seismic activity must be taken into account when allowing new disposal wells in other parts of the state.

Photo

Tanks hold contaminated water in Texas from hydraulic fracking, a practice believed to have contributed to elevated rates of earthquakes. CreditJerod Foster for The Texas Tribune

Last year, the Railroad Commission of Texas and the oil and gas industry there agreed to new rules allowing the commission to shut down old wells and deny permission for new ones based on earthquake risks.

The issue has serious political, economic and environmental implications, particularly in the nation’s midsection, where energy production and related jobs have soared.

Zachary Cikanek, a spokesman for the American Petroleum Institute, said that from an environmental standpoint, underground disposal wells remain one of the best options available. He noted that the Environmental Protection Agency has released new guidelines to help regulators make decisions regarding issues like well placement and appropriate injections rates for fluids.

The report said two adjacent regions were most affected: one largely in northern Oklahoma but extending into southern Kansas, and the other stretching from central Oklahoma to the Texas border, where seismic activity has soared in the last six years.

It also mapped parts of Texas where it said wastewater injection wells had produced quakes, including the heavily populated Dallas-Fort Worth area. Other risk areas named were in Colorado, including one that extends into Utah, and in Alabama, Arkansas, New Mexico and Ohio.

“We’re seeing these induced earthquakes much more often than we ever used to, in multiple parts of the country, and we need to try to understand the risks and how to deal with them,” Mr. Petersen said.

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GRAPHIC

Quakes in OklahomaMaps showing a rise in the number of earthquakes.

  OPEN GRAPHIC

Thousands of small quakes occur every year around the country, noticed only by the jittering needles of seismographs; a magnitude 3 temblor is felt by some people relatively close by, but the only harm is to their nerves. But the scale used to measure earthquakes is logarithmic, meaning that a magnitude 4 quake is 10 times as powerful as a magnitude 3, and a magnitude 5 — strong enough to do some structural damage — is 10 times as powerful as a magnitude 4.

In 2011, central Oklahoma experienced the most powerful earthquake recorded in the state, a 5.6-magnitude shock that scientists have also called the nation’s biggest human-induced quake. By comparison, the major quake that struck Los Angeles in 1994 measured 6.7, and the one that hit the San Francisco Bay Area in 1989 measured 6.9.

The highly technical report was a step toward predicting the risk from human-caused quakes, which it conceded was extremely hard to do. “Difficulties in assessing seismic hazard arise from a lack of relevant technical information on human industrial activity (that is, pumping data for injection wells),” the report said.

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Mr. Petersen noted that wastewater disposal and related earthquakes “fluctuate year by year based on economic and policy decisions, which are very difficult to predict.” In fact, the report shows that in places where wastewater injection stopped, earthquake frequency fell to near zero — notably, in central Arkansas since 2011 and in an area north of Denver in the 1970s.

Predicting risk is also hard, the report noted, because there is no scientific consensus on just how powerful such quakes can be. The report estimated the effects of shocks up to magnitudes 6 and 7, while noting that some scientists have speculated that the catastrophic 7.9-magnitude earthquakein China in 2008 was caused by human activity.

“I’m not necessarily saying that we’re going to have a 7 in Oklahoma,” Mr. Petersen said. “But I don’t think we can rule that out.”

Scientists have also posited that human-caused quakes could lead to additional ones on naturally occurring faults nearby.

The agency’s assessments of naturally occurring earthquake risks are often used to help determine building codes and set insurance rates. Buildings in the middle of the country, unlike those on the West Coast, generally do not have to meet seismic safety standards.

Correction: April 26, 2015 

An earlier version of this article, because of an errant email response, said incorrectly that the American Petroleum Institute had not answered a request for comment. The organization’s comment has now been included to the article.

John Schwartz and Michael Wines contributed reporting.

A version of this article appears in print on April 24, 2015, on page A1 of the New York edition with the headline: U.S. Maps Pinpoint Earthquakes Linked to Quest for Oil and Gas. Order Reprints| Today's Paper|SubscribeNEXT IN U.S.

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