Several of you have asked me for a nice, meaty post about whether fracking causes earthquakes. The bad news is: I haven't written one. The good news is: lots of other folks have! And the best news: I've got them all right here for you.

The upshot is: yes, fracking can cause earthquakes, but most of the induced earthquakes in the United States are caused by wastewater injection. Come find out more!

 

FiveThirtyEight: How The Oil And Gas Industry Awakened Oklahoma’s Sleeping Fault Lines

There has always been a connection between petroleum and faults. Faults are places where the earth doesn’t quite align, like the planet buttoned its shirt up the wrong way. And the forces that create them also create pockets in the Earth that trap deposits of oil and gas. It makes sense that a place with a lot of one might also have a lot of the other, and the history of Oklahoma has been intimately connected to both. The first recorded earthquake there occurred in 1882, and the first commercially successful oil well was drilled in 1897 — both before Oklahoma was even a state. Today, it produces more natural gas than oil, but oil pump jacks are still a common sight, dipping and rising like great, beaked herons on roadsides, in random backyards, and — in the town of Barnsdall — literally in the middle of Main Street.

Before 2008, Oklahoma had maybe a couple of earthquakes of magnitude 3 or greater each year, said George Choy, a research geophysicist with the USGS who studies human-caused quakes. In 2015, it had around 900. The evidence studied by scientists like Choy and Hough strongly suggests that this increase was caused by the practice of injecting wastewater from oil and gas extraction — both conventional and fracking — back into the earth. To understand why that is, and why those same scientists can’t tell you whether any individual earthquake was caused by the petroleum industry, you have to pay attention to the faults.

USGS Earthquake Hazards Program: Induced Earthquakes 

Within the central and eastern United States, the number of earthquakes has increased dramatically over the past few years. Between the years 1973–2008, there was an average of 21 earthquakes of magnitude three and larger in the central and eastern United States. This rate jumped to an average of 99 M3+ earthquakes per year in 2009–2013, and the rate continues to rise. In 2014, alone, there were 659 M3 and larger earthquakes. Most of these earthquakes are in the magnitude 3–4 range, large enough to have been felt by many people, yet small enough to rarely cause damage. There were reports of damage from some of the larger events, including the M5.6 Prague, Oklahoma earthquake and the M5.3 Trinidad, Colorado earthquake.

This increase in earthquakes prompts two important questions:

  • Are they natural, or man-made?

  • What should be done in the future as we address the causes and consequences of these events to reduce associated risks?

There are a lot of resources on this page - set aside time to explore!

USGS Earthquake Hazards Program: Myths and Misconceptions

A very useful list of facts about fracking and induced earthquakes.

Seismological Research Letters: Myths and Facts on Wastewater Injection, Hydraulic Fracturing, Enhanced Oil Recovery, and Induced Seismicity

The central United States has undergone a dramatic increase in seismicity over the past 6 years..., rising from an average of 24 M ≥ 3earthquakes per year in the years 1973–2008 to an average of 193 M ≥ 3 earthquakes in 2009–2014, with 688 occurring in 2014 alone. Multiple damaging earthquakes have occurred during this increase including the 2011 M 5.6 Prague, Oklahoma, earthquake; the 2011M 5.3 Trinidad, Colorado, earthquake; and the 2011M 4.7 Guy-Greenbrier, Arkansas, earthquake. The increased seismicity is limited to a few areas and the evidence is mounting that the seismicity in many of these locations is induced by the deep injection of fluids from nearby oil and gas operations. Earthquakes that are caused by human activities are known as induced earthquakes. Most injection operations, though, do not appear to induce earthquakes. Although the message that these earthquakes are induced by fluid injection related to oil and gas production has been comunicated clearly, there remains confusion in the popular press beyond this basic level of understanding.
 
In this article, we attempt to dispel the confusion for a nonspecialist audience.

Oklahoma Geological Survey: Oklahoma Geological Survey

Lots of information on the ongoing earthquake research and monitoring in a state hit very hard by induced earthquakes.

The Wichita Eagle: New fault line discovered after 5.8 Oklahoma earthquake 

A magnitude-5.8 earthquake and a series of smaller aftershocks in Oklahoma has led to the discovery of a new fault line.

The discovery stoked fears among some scientists about other unknown faults that could be triggered by oil and gas wastewater that’s being injected deep underground.

State and federal regulators this week said 32 disposal wells in northeastern Oklahoma must shut down because they are too near the newly discovered fault line that produced the state’s strongest earthquake on record on Sept. 3.

The quake shook Wichita and many other parts of Kansas. It caused minor damage to some city and county buildings.