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Wastewater well depths linked to Oklahoma quakes

Adapted from Hincks et al., 2018, “Oklahoma’s induced seismicity strongly linked to wastewater injection depth”; Map: Lazaro Gamio / Axios

Scientists know that wastewater injection related to fracking for oil and gas can induce earthquakes. A new study published in Science Thursday found that the deeper these injections go towards a layer of rock called the crystalline basement, the more likely they are to cause earthquakes.

Why it matters: Oklahoma never used to experience many earthquakes, but since 2009, a number of damaging temblors have shaken the area. "State regulators could cut about in half the number of man-made quakes by restricting deep injections in the ground," study author Thea Hinck told the Associated Press.

What they did: The researchers developed a statistical model to evaluate the relationship between well operations (including the depth and rate of injection and the volume of liquids), the geology surrounding the wells, and earthquakes.

  • They evaluated all the Class II wells (used for oil and gas production) in Oklahoma and studied the seismic activity there.
  • There were 2,264 earthquakes of magnitude 3 or greater recorded in the state for the six-year-period of collected data.

What they found: Restricting injection depths to 200–500 meters above the basement level could reduce earthquakes by a factor of 1.2–2.8.

  • Location matters: "It turns out there are patches of higher and lower potential within the broader zone, and this affects how likely it is any particular well will be implicated in earthquake trigger," study author Thomas Gernon tells Axios.

Another perspective: U.S. Geological Survey's Art McGarr, a geophysicist not part of this study, told Axios most of the study's findings had been shown before. However, he says it's important to continue research.

"In Oklahoma, it is especially important to understand the causes of seismic activity because this source of hazard can be controlled, in contrast to natural seismicity, which is beyond human control," he says.

Editor's note: The headline was corrected to reflect the wells in the study were wastewater injection wells and not fracking wells.

Steve LeVine 11 hours ago
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The stakes for who wins the AI race

A sentient computer saying 'Hello World' in English, Chinese and Russian.
Illustration: Lazaro Gamio/Axios

One of the most urgent themes in technology is the global rivalry for dominance of the evolving sector of artificial intelligence — geopolitical and economic supremacy is said to be at stake. Experts view the U.S. and China as the top contenders, but other nations, including Russia, are working on AI, too.

What it means: In its latest edition, the Economist draws a sharp line as to the extraordinary ramifications of the race. "The global spread of a technosystem conceived in, and to an unknown extent controlled by, an undemocratic, authoritarian regime could have unprecedented historical significance," the magazine wrote.

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Airlines may not be the "germ incubator" you thought

Inside of an airplane
Photo: via Getty Images

The chance of becoming infected with a common respiratory virus on an airplane may be smaller than originally thought — less than 3% unless you are sitting within one meter of an infected person, where your chances rise to 80%, according to a study published in PNAS Monday.

Why it matters: There are more than 3 billion airline passengers annually, and global health officials want to learn more how infectious diseases are transmitted, particularly after reported transmission of cases of flu pandemic and severe acute respiratory syndrome (SARS) via planes.