A new study by scientists from the U.S. Geological Survey, not yet published but scheduled to be presented at the upcoming annual meeting of the Seismological Society of America, reports a dramatic increase in earthquakes of magnitude 3.0 or greater over a large area of the U.S. More interestingly, the report states that the increase is “almost certainly man-made,” and attributes it to oil and gas production.
MSN reports thus:
The study said a relatively mild increase starting in 2001 comes from increased quake activity in a methane production area along the state line between Colorado and New Mexico. The increase began about the time that methane production began there, so there’s a “clear possibility” of a link, says lead author William Ellsworth of the USGS.
Since I’m a data junkie, I retrieved some data on earthquake occurrences in the study region. The data I retrieved are from only one of the catalogues used in the USGS study, and I haven’t applied the control measures used by the study authors, so my numbers don’t theirs match exactly — but it should at least give us an idea whether or not there is an obvious increase in earthquakes as dramatic as reported.
Annual counts of earthquakes of magnitude 3.0 or greater looks rather like, well, a hockey stick:
Monthly counts look rather like, well, a hockey stick:
What really surprised me about the news report, and gave me a distinct feeling of deja vu, was not the dramatic (truly!) increase in earthquakes or its attribution to human activity. It was what the Oklahoma state seismologist had to say. I already expected him to cast doubt on the findings for political rather than scientific reasons, because Oklahoma is so deeply involved with the fossil fuel industry. What amazed me was how he attempted to do so:
Austin Holland, the Oklahoma state seismologist, said the new work presents an “interesting hypothesis” but that the increase in earthquake rates could simply be the result of natural processes.
Holland said clusters of quakes can occur naturally, and that scientists do not yet fully understand the natural cycles of seismic activity in the central United States. Comprehensive earthquake records for the region go back only a few decades, he said, while natural cycles stretch for tens of thousands of years. So too little is known to rule out natural processes for causing the increase, he said.
Does that sound familiar?
Perhaps what should surprise me is that he didn’t blame it on galactic cosmic rays. Or movement of the sun around the solar system barycenter. Or the moon. But we all know the real reason: leprechauns.