Sharp Rise In U.S. Earthquakes Directly Linked To Fracking Wastewater Reinjection

[limpyhobbler]

Distant Quakes Trigger Tremors at U.S. Waste-Injection Sites

"Cumulative count of earthquakes with a magnitude ? 3.0 in the central and eastern United States, 1967–2012. The dashed line corresponds to the long-term rate of 21.2 earthquakes per year, with an increase in the rate of earthquake events starting around 2009." Via USGS

A surge in U.S. energy production in the last decade or so has sparked what appears to be a rise in small to mid-sized earthquakes in the United States. Large amounts of water are used both to crack open rocks to release natural gas through hydrofracking, and to coax oil and gas from underground wells using conventional techniques. After the gas and oil have been extracted, the brine and chemical-laced water must be disposed of, and is often pumped back underground elsewhere, sometimes causing earthquakes.

http://thinkprogress.org/climate/2013/07/14/2291931/shale-shocked-sharp-rise-us-earthquakes-linked-to-fracking-wastewater-reinjection/

[caraher]

1. What a peculiar way to graph the data

I'm OK with using its slope to find the long-term average earthquake rate (though just averaging pre-2008 or 2009 annual figures would give the same result).

But this makes it hard to see just how much the earthquake rate has jumped.

[limpyhobbler]

2. Yeah I was wondering about that too.

Don't know why they graphed it like that. Who counts cumulative earthquakes?

Here's a link from USGS. Seems like a pretty big increase.

The number of earthquakes has increased dramatically over the past few years within the central and eastern United States. More than 300 earthquakes above a magnitude 3.0 occurred in the three years from 2010-2012, compared with an average rate of 21 events per year observed from 1967-2000.

http://www.usgs.gov/blogs/features/usgs_top_story/man-made-earthquakes/



Mentally rotate the graph 45 degrees clockwise maybe? It's a flat line with an increase around 2009.

Also there seems to be a leveling off or decreased slope at the very far right side of the graph, around 2011. I'm guessing that's because people started complaining about earthquakes, so the industry started dialing down the injection pressure.

[caraher]

3. Upon close inspection...

it looks like what they did was something like a daily plot of the cumulative total of quakes. (maybe weekly; but clearly with finer time resolution than yearly or monthly)

So I think there's some convenience involved in making a plot that way... though given the raw data it would be pretty simple to break into annual "bins"