We are searching data for your request:
Upon completion, a link will appear to access the found materials.
Much more than the only earthquake of that magnitude that occurred in the previous three decades.
And what is responsible for that notable increase in frequency, say scientists from the United States Geological Survey (USGS), is the wastewater management technique of companies that use the hydraulic fracturing method to extract gas or oil. High pressure water
Fracking is a technique that allows the extraction of oil or so-called shale gas, a type of unconventional hydrocarbon that is literally trapped in layers of rock, at great depth. To reach and fracture the shale rock, a large amount of water is drilled and injected under high pressure with chemical additives to release the gas, methane.
Between 25% and 75% of the injected fluid returns to the surface, according to the Royal Society, the British Academy of Sciences. And that wastewater is stored in open-pit ponds dug into the ground, treated and reused, or, as in the case the USGS studied, injected at high pressure into rock formations, in underground reservoirs.
USGS experts noted that since companies began injecting large amounts of wastewater into underground wells in Colorado and New Mexico, what was once a seismically quiet area has had 16 earthquakes.
In addition, scientists point out, the epicenter of all earthquakes has been very close to these hydraulic injection wells.
In the graph, which shows all the earthquakes recorded in the Raton Basin, the circles mark the magnitude and the white squares, the sewage wells.
"The increase in earthquakes is limited to the area of industrial activity and within a 5km radius of the wastewater injection wells," says the study signed by geophysicist Justin Rubistein. According to the federal agency scientist, most of the wastewater injection wells in the United States are the result of the extraction of gas and oil.
"We think that in some of those injection wells the fluids work their way up to the (tectonic) faults in the area and, in some sense, lubricate them, facilitate earthquakes," Rubinstein said, as reported by Colorado Public Radio.
The work of the team led by Rubinstein offers a detailed historical review of the Ratón sedimentary basin - in southern Colorado and northern New Mexico - which has seen a boom in natural gas production in the last twenty years, along with the industry's need to dispose of wastewater.
Their findings will be published in the October issue of the Bulletin of the Seismological Society of America.
The new report coincides with the publication of a study in the scientific journal of the American Academy of Sciences that suggests that another problem related to facking, contamination of drinking water with shale gas, is due to defects in wells and not directly to hydraulic fracturing.
The researchers analyzed the water contained in 130 wells in Pennsylvania and Texas, and followed the trail of methane, to conclude that the gas leakage is due to the poor lining of those deposits.
Water contamination by additives or methane leaks and the occurrence of earthquakes are the main risks pointed out by fracking detractors.
Anthony Ingraffea, an engineering professor at Cornell University in the US, told BBC Mundo at the time that "the best operational practices can only minimize risks, not eliminate them," adding that "even today we see that at least 5% of the new wells being built in the United States have methane leaks. "
However, the promoters of this technique say that it responds to the growing demand for energy with resources cleaner than coal.
According to the International Energy Agency, the extraction of shale gas by hydraulic fracturing could lead the United States to achieve energy self-sufficiency by 2035.
But fracking continues to generate protests not only in the US but in other nations such as the United Kingdom and Argentina, and it is prohibited in France and in New York state itself.
BBC Mundo http://www.bbc.co.uk/