Fracking and earthquakes

From the website Science Daily (here).

How Shale Fracking Led to an Ohio Town’s First 100 Earthquakes

Aug. 19, 2013 — Since records began in 1776, the people of Youngstown, Ohio had never experienced an earthquake. However, from January 2011, 109 tremors were recorded and new research in Geophysical Research-Solid Earth reveals how this may be the result of shale fracking. In December 2010, Northstar 1, a well built to pump wastewater produced by fracking in the neighboring state of Pennsylvania, came online. In the year that followed seismometers in and around Youngstown recorded 109 earthquakes; the strongest being a magnitude 3.9 earthquake on December 31, 2011. The study authors analyzed the Youngstown earthquakes, finding that their onset, cessation, and even temporary dips in activity were all tied to the activity at the Northstar 1 well. The first earthquake recorded in the city occurred 13 days after pumping began, and the tremors ceased shortly after the Ohio Department of Natural Resources shut down the well in December 2011. Dips in earthquake activity correlated with Memorial Day, the Fourth of July, Labor Day, and Thanksgiving, as well as other periods when the injection at the well was temporarily stopped. “In recent years, waste fluid generated during the shale gas production — hydraulic fracturing, had been increasing steadily in United States. Earthquakes were triggered by these waste fluid injection at a deep well in Youngstown, Ohio during Jan. 2011 — Feb. 2012. We found that the onset of earthquakes and cessation were tied to the activity at the Northstar 1 deep injection well. The earthquakes were centered in subsurface faults near the injection well. These shocks were likely due to the increase in pressure from the deep waste water injection which caused the existing fault to slip,” said Dr. Won-Young Kim. “Throughout 2011, the earthquakes migrated from east to west down the length of the fault away from the well — indicative of the earthquakes being caused by expanding pressure front.”

EQC drilling update

EQC have updated information on their drilling programme here. The information covers:

  • Major drilling program completed
  • Shallow geotechnical investigations (useful for those who don’t need a major geotechnical investigation).
  • Accessing a copy of the shallow geotechnical investigation findings

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Maps of lateral spreading and other earthquake effects in Avonside

Courtesy of a blog reader I have discovered a Tonkin & Taylor report on lateral spread in the Avonside Area. The full title is Appendix M: Avonside study area – lateral spreading. The EQC website is currently closed however you can download it from here.

On the same website, but this page here, is more geotechnical information arising from the Liquefaction Vulnerability Study (mentioned on the blog earlier in the month here). There is a huge range of stuff however, as Avonside is the only suburb for which there are detailed maps, possibly nothing informative for those in other Red Zoned areas.

The report is a collection of maps that show measured changes in height, and ground surface observations of liquefaction, ground cracking and lateral spread throughout Avonside. The time period of the maps is from September 2010 through to at least the June earthquakes in some cases, and December 2011 in others. The report itself is undated.

For those who have some doubts about what happened this is a good set of maps to check what you observed against what was recorded by Tonkin & Taylor. If you are stuck for a place to start try Map 6. This map shows the amount of land movement over the period. The longer the arrow the more movement there was (there is a scale for the arrows at the bottom of the map). If my eye-balling is correct then the land under Cowlishaw Street moved about half a metre and the land under Bracken Street moved well over a metre. Land under Dallington by the Gayhurst Bridge moved close to two metres.

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Wastewater injection caused a 5.7 earthquake in the USA

Injection of water into the ground by the oil industry has been considered a threat to land stability by many. It is dismissed by those who benefit from the oil extraction associated with fracking, and the disposal of waste fluids by injection back into the ground. In the USA a 2011 series of earthquakes (the maximum 5.7) in central Oklahoma have been attributed to the injection of wastewater deep underground. The wastewater was produced as a result of oil extraction in the area:

The water linked to the Prague quakes was a by product of oil extraction at one set of oil wells, and was pumped into another set of depleted oil wells targeted for waste storage.

A media release from a study involving Columbia University and the US Geological Survey has drawn attention to this connection. As the media release explains, the presence of faults near to where these processes occur are at risk of earthquakes. Part of a scientific media release is below. The full release is on the website Science News here.

The magnitude 5.7 quake near Prague (Oklahoma) was preceded by a 5.0 shock and followed by thousands of aftershocks. What made the swarm unusual is that wastewater had been pumped into abandoned oil wells nearby for 17 years without incident. In the study, researchers hypothesize that as wastewater replenished compartments once filled with oil, the pressure to keep the fluid going down had to be ratcheted up. As pressure built up, a known fault — known to geologists as the Wilzetta fault–jumped. “When you overpressure the fault, you reduce the stress that’s pinning the fault into place and that’s when earthquakes happen,” said study coauthor Heather Savage, a geophysicist at Columbia University’s Lamont-Doherty Earth Observatory. The amount of wastewater injected into the well was relatively small, yet it triggered a cascading series of tremors that led to the main shock, said study co-author Geoffrey Abers, also a seismologist at Lamont-Doherty. “There’s something important about getting unexpectedly large earthquakes out of small systems that we have discovered here,” he said. The observations mean that “the risk of humans inducing large earthquakes from even small injection activities is probably higher” than previously thought, he said. Hours after the first magnitude 5.0 quake on Nov. 5, 2011, University of Oklahoma seismologist Katie Keranen rushed to install the first three of several dozen seismographs to record aftershocks. That night, on Nov. 6, the magnitude 5.7 main shock hit and Keranen watched as her house began to shake for what she said felt like 20 seconds. “It was clearly a significant event,” said Keranen, the Geology study’s lead author. “I gathered more equipment, more students, and headed to the field the next morning to deploy more stations.” Keranen’s recordings of the magnitude 5.7 quake, and the aftershocks that followed, showed that the first Wilzetta fault rupture was no more than 650 feet from active injection wells and perhaps much closer, in the same sedimentary rocks, the study says. Further, wellhead records showed that after 13 years of pumping at zero to low pressure, injection pressure rose more than 10-fold from 2001 to 2006, the study says

The full release is here. The scientific journal reference is: Katie M. Keranen, Heather M. Savage, Geoffrey A. Abers, and Elizabeth S. Cochran. Potentially induced earthquakes in Oklahoma, USA: Links between wastewater injection and the 2011 Mw 5.7 earthquake sequence. Geology, March 26, 2013 DOI: 10.1130/G33909.1 .