DENVER – When a 5.3 magnitude earthquake rattled Southern Colorado three years ago near Trinidad, scientists wondered what could have caused it. This week, they got their answer.
The U.S. Geological Survey says humans are to blame. More specifically: waste-water injections done by the oil and gas industry.
"We weren't very surprised," said Arthur McGarr, a USGS Researcher. "The earthquakes coincided pretty much with the time and history of the waste water injection in some fairly high volume wells".
Arthur McGarr worked on the USGS study. He says two things lead scientists to the waste water injection conclusion:
"The proximity of the earthquakes to these very high volume injection wells were quite a substantial tip off," McGarr said.
USGS Researchers also noticed a remarkable increase in the rate of detected earthquakes in the same area, compared to what had been reported decades before.
"There was approximately a one year time delay when injections started and when the earthquakes began to be noticed," McGarr said.
Scientists say the injection of wastewater is different than fracking, although USGS researchers believe fracking can cause earthquakes as well.
"I think the main message is it's important to monitor the waste water disposal wells and find out early on what the seismic response is likely to be," McGarr said.
In a recent interview with Colorado Public Radio, the Colorado Oil and Gas Association, known as COGA, said they were reviewing the report released by the USGS and also said their wells are 'safe'.
COGA represents the energy industry. The sent the following statement:
In regards to your question - we take this issue very seriously and will continue to work with our federal and state regulators. We always appreciate new scientific, relevant data that allows industry to ensure the continued safe operation of underground injection control (UIC) wells. UIC wells are highly regulated by the state and federal government. It is important to note that there are over 300 Class 2 oil and gas UIC wells in the State of Colorado, and this study is only considering a few of those 300 wells.
On the state side of things, the Colorado Oil and Gas Conservation Commission told 9NEWS it is, "closely reviewing the USGS report and is in communication with its authors". It also says "If necessary, measures related to altering injection rates, pressures and frequencies – then studying the effects, if any – could be employed to manage seismicity risks".
The USGS's report will be published in October. To read it now, follow this link: http://www.cpr.org/sites/default/files/rubinstein_article.pdf
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