Fracking and Earthquakes: The Tightest Link Yet

Stanford scientists have found the best evidence so far that injections of wastewater from hydraulic fracturing (fracking) oil and gas wells definitely cause earthquakes.  The next question is, how will the Texas Railroad Commission and the oil and gas industry respond?  But first, the scientists' study.

As readers of this blog may know, fracking involves the injection of special mixtures of water and proprietary stuff at extremely high pressure into specially drilled wells that penetrate oil- and gas-bearing formations which normally would not produce enough to be worth drilling into.  The producing wells are not the problem.  The problem is that a byproduct of the process is a huge amount of wastewater contaminated with salt, chemicals, and sometimes even radioactive stuff, and these days you don't just dump it out on the ground or into a nearby stream.  The drillers gather it up with tank trucks and ship it to disposal wells, where it is squirted several kilometers deep into rock formations under tremendous pressure. 

It's these disposal wells that seem to be associated with spates of earthquakes in north Texas and Oklahoma, which up to 2000 or so were some of the most earthquake-free areas in the U. S.  Fortunately, most of the earthquakes have been small—around 3 on the "moment magnitude" scale, which replaced the old Richter scale in the 1970s.  But a 4.8-magnitude quake on May 17, 2012 in the East Texas town of Timpson (about halfway between Lufkin and Longview) knocked down a brick wall, and turned out to be the largest such quake ever recorded in that area in recent times. 

Stanford geologist William Ellsworth, working with an international team of geophysicists, remote sensing experts, and others, decided to build a model of the subsurface rocks to see if they could reproduce the conditions that may have led to the earthquake.  Fortunately, that part of Texas is well-understood geologically, and Ellsworth's team obtained data on how much wastewater was injected into two pairs of wells, each at a different depth.  They also found and enhanced satellite-radar data that can measure movement at the earth's surface as slight as 1 millimeter per year.  They put all this data into a "poroelastic layered Earth model," meaning they accounted for porosity and elasticity—how holey and how flexible the rocks are.  They also knew about existing faults, and ran their model to predict both how much the surface might bulge after getting some 800,000 cubic meters of wastewater injected into it per year for several years.  Then they compared their model's predicted bulge to the measured bulge, which was several centimeters, and got pretty good agreement between their model and the actual satellite data.

That told them that another number their model produced—the increase in pore pressure—was also probably right.  When pore pressure increases by about 10 times atmospheric pressure (1 megapascal or more), this has been shown to cause earthquakes.  The mechanics are complicated, and I'm not a mechanical engineer.  Basically, the reason fault lines under pressure don't slip is that there is a lot of force squeezing the two sides together, and the resulting friction keeps things stationary.  But when you have increased pore pressure on the order of 1 megapascal, that somehow decreases the squeezing force and the thing starts to slip.  And slip it did, causing Timpson's quake and others.

Although most of the bulging occurred around the eastern pair of wells, the western wells were where the earthquake happened.  Ellsworth's team could explain this by citing differences in the porosity and elasticity of the rocks around each set of wells. 

So the scientists have made a model of the rocks under Timpson, injected their rock model with wastewater, and observed both a surface bulge that matches what satellites actually measured, and noted pore-pressure changes of a size that is known to cause earthquakes elsewhere.  And in fact, an earthquake happened.  Looks pretty conclusive to me.  But I'm not a Texas Railroad Commissioner.

What have railroads got to do with oil and gas production?  It's a long story, but basically, the Texas Railroad Commission (TRC), which originally did regulate railroads, backed into the business of granting permits for oil and gas production in the 1930s, and as time went on nobody has had the temerity to change its name.  It apparently did some useful work in the 1930s by putting the brakes on absurd overproduction and keeping oil prices from vanishing.  Nowadays, its regulatory duties are different, and involve environmental concerns as well as the usual support and encouragement of the industry it is charged with regulating. 

In reports describing the Stanford study, attempts by reporters to get a reaction out of the TRC were initially unsuccessful.  The Commission's mission statement has three bullets, saying it serves Texas through (1) "our stewardship of natural resources and the environment" (2)  "our concern for personal and community safety" and (3) "our support of enhanced development and economic vitality for the benefit of Texans."  Judging by the Commission's past reluctance to admit any causal link between fracking and earthquakes, their mission statement's bottom line, about enhancing development and economic vitality, appears to be taking precedence over the other two items, just as a company's bottom line tends to take precedence over other concerns.

Ellsworth and company have confirmed what many other geologists, as well as numbers of ordinary citizens, have been suspecting for a long time.  Most, if not all, of the increased earthquake activity in regions near wastewater injection wells can probably be attributed to those wells. 

By and large, Texans are reasonable people.  Fracking has been an economic blessing to many parts of the state, and it's unlikely that anything like the blanket fracking bans in New York and Maryland could happen here.  But now that there is reasonably good evidence of the connection between wastewater wells and earthquakes, it would only be reasonable for people who have lost property or been injured in such events to ask for compensation from the owners of the wells.  Of course, any time lawyers get involved, reason may fly out the window, but I think we can work these issues out without either continuing to deny that there's any association at all, or saying that fracking is an invention of the Devil and must be abolished from the planet.  Let's hope so, anyway.

Sources:  I referred to a report published online by the Dallas Observer on Sept. 23, 2016 at http://www.dallasobserver.com/news/new-scientific-study-cites-direct-evidence-that-texas-quakes-are-manmade-8736998, one in the Dallas Morning News at http://www.dallasnews.com/news/state/headlines/20160923-texas-quakes-caused-by-injection-wells-scientists-determine.ece, and the paper by M. Shirzaei, W. L. Ellsworth, K. F. Tiampo, P. J. González, and M. Manga, "Surface uplift and time-dependent seismic hazard due to fluid injection in eastern Texas," Science, vol. 353, Issue 6306, pp. 1416-1419, as well as the Texas Railroad Commission website www.rrc.state.tx.us.

Earthquake Prediction Goes Commercial — Sort Of

Everybody's now used to seeing weather maps with "past" and "future" buttons on them, allowing you to see what the weather is likely to be a day or two ahead of time.  Did you know there is at least one company that is now publishing a similar map of the world that depicts regions that may shortly experience earthquakes?  QuakeFinder, which calls itself a "humanitarian R&D project" of a parent firm named Stellar Solutions, has a Public Data Center page where they put little red dots in regions that have experienced a change in electromagnetic activity, which (according to QuakeFinder) has been correlated with future earthquakes.  I don't know how much traffic their site attracts, and so far I haven't seen any red dots show up, but I just found out about the site today. 

QuakeFinder bases their predictions on three types of data:  (1) ultra-low-frequency (ULF) magnetic fields, (2) concentration of ions in the air, and (3) emission of infrared radiation as monitored by satellites.  A number of studies over the last few decades have turned up situations in which disturbances in all three quantities have preceded medium to large earthquakes in many locations.  Of course, it's a long stretch between noticing some correlations and using data to make specific predictions about earthquakes.  But at least two organizations—QuakeFinder and another outfit called GeoCosmo—seem to think that there's enough data to start estimating the timing, location, and size of future earthquakes.

I will leave the question of whether QuakeFinder's predictions are accurate aside for the moment, and turn to what might be an even more vexing issue:  once you have a way of predicting earthquakes with some degree of precision, what should you do with it?

A lot depends on the level of false positives (times you say there will be a quake and nothing, or almost nothing, happens) and false negatives (times you miss making a prediction and an earthquake catches you by surprise).  Let's say for the sake of argument that the system does as well at predicting earthquakes as today's weather forecasters do at predicting tornado activity.  I don't have exact statistics on hand at the moment, but my sense is that the great majority of the time when a region is in a tornado watch, some violent weather usually occurs—either a tornado or high winds that can cause as much damage as a small tornado.  And the weather prophets very rarely get caught napping nowadays by failing to predict violent weather, although there are times when a storm becomes a lot worse than forecasts predicted.

At one extreme, it would be the height of moral irresponsibility to know that a major earthquake is going to hit a populated area (where "know" means, say, an 80% chance), and not do anything to let the affected people take precautions.  So the development of a truly reliable earthquake prediction system carries with it the moral obligation to share the information in some form with the general public.

On the other hand, what sorts of precautions should be taken if earthquake prediction becomes a reality?  I can imagine different degrees of preparedness for different groups.  First responders and emergency services would take such predictions most seriously by increasing reserve staffing and supplies and heightening their readiness for a crisis.  People in structures that are known to be especially vulnerable to earthquake damage might consider just staying away for a few days.  Depending on how far in advance a quake could be predicted, this could be a problem. 

It's not clear yet whether earthquake prediction will share with tornado prediction the characteristic that shorter time spans mean more accurate predictions.  If a weather radar shows a tornado two miles west of you heading east at thirty miles an hour, it's pretty easy to say you'll be in big trouble in about four minutes.  It's possible that the best earthquake predictions may never provide time windows narrower than many hours or even days.  Making people stay home or in earthquake-resistant shelters for several days is simply not going to fly, so a lot will depend on how chronologically precise the predictions can be made. 

Another important question is, who's going to pay?  When scientific prediction of weather first became possible in the late 1800s, the economic and military advantages of doing so were so obvious that most national governments established weather bureaus or the equivalent, and for many years government weather prediction was the only show in town.  The observation end of weather forecasting—all those weather stations, weather satellites, and people keeping records for decades—is still expensive, and borne largely by government agencies, but a large number of private weather-forecasting firms now take government data and use it for both public predictions through the media and specialized predictions through commercial transactions.

So far, the model used by QuakeFinder is a non-profit one, although the line dividing a non-profit organization from a commercial operation is not always that easy to draw.  QuakeFinder does apparently have "subscribers" who presumably get customized data.  Weather bureaus and weather forecasting prospered because their forecasts were accurate enough to be valuable, and we can expect earthquake forecasting to be held to a similar standard.  On its website, QuakeFinder claims to have predicted a couple of Peruvian earthquakes, which claim is confirmed indirectly by contemporary news reports citing the involvement of a "California company" (presumably QuakeFinder) in a prediction by a Peruvian scientist of two medium-size earthquakes in Peru in April of 2013. 

But just as two swallows don't make a summer, two predictions don't make a successful prediction system.  Large segments of the scientific community remain unconvinced that earthquake prediction is anything more than a slightly informed guess.  According to some sources (including journalist Alberto Enriquez), one of the biggest wet blankets on earthquake prediction is the United States Geological Survey (USGS).  Apparently back in the 1980s, this agency received extra funding to develop earthquake predictions, and they got burned when their forecast of a major earthquake (again in Peru) failed to materialize in 1981.  Ever since, according to Enriquez, they have been critical of earthquake prediction and have made it hard for researchers to publish in this area or to receive funding.

But other agencies such as the National Aeronautics and Space Administration (NASA) are supporting the work of researchers such as Friedemann Freund, who has been mentioned previously in this space as the developer of a theory (confirmed by experiments) that stressed rocks can produce large electric and magnetic fields when mobile charge carriers he calls "p-holes" arise in them.  Freund is one of the founders of GeoCosmo, which focuses on earthquake prediction studies.

The nice thing about private enterprise is that it's self-limiting.  If QuakeFinder or GeoCosmo get it right often enough, people will start paying attention.  Let's hope they can figure out how to do it and get taken seriously enough to save some lives before the next big quake hits.

Sources:  I thank Alberto Enriquez for drawing my attention to recent developments in this field through his website http://seismoem.com/blog/earthquake-forecasting-is-here-today.  QuakeFinder's website is at https://www.quakefinder.com/.  GeoCosmo's website is geocosmo.org.  A news report on June 25, 2013 providing independent confirmation of the Peruvian earthquake prediction attempt is at http://www.peruthisweek.com/news-peruvian-geologists-may-be-able-to-predict-earthquakes-100220.  I also referred to an article by Julia Rosen carried on the American Association for Advancement of Science Science website, entitled "Can electric signals in Earth's atmosphere predict earthquakes?" at http://www.sciencemag.org/news/2015/12/can-electric-signals-earth-s-atmosphere-predict-earthquakes.  Friedemann Freund's research in "seismoelectromagnetics" (the electric and magnetic fields produced by stressed rocks) was summarized in this space in "Global Warming or Global Shaking?  A Tale of Two Theories" on Feb. 20, 2007.

Is Fracking Shaking Up Azle?

Although Texas has had its share of both natural and man-made disasters, earthquakes are not something most Texans worry about much.  The geology of much of Texas is more or less flat limestone layers left over from the time when a giant sea covered much of the state.  We are pretty far away from the edges of tectonic plates, unlike places such as the west coast of the U. S., where earthquakes are a constant threat.  So when the small North Texas town of Azle had an earthquake a year or two ago, it was an unusual event.  It was a small one, but more and more followed.  In the month-long period ending today (Dec. 29), Azle has had ten earthquakes large enough to be noted by the website earthquaketrack.com, whose data comes from the United States Geological Survey.  The smallest was magnitude 2.8 and the largest was 3.6, which is enough to rattle windows and cause minor structural damage. 

This would be simply a matter of scientific curiosity were it not for the possibility that these earthquakes, as well as similar ones in other parts of Texas and the U. S., are related to oil- and gas-drilling activity.  Specifically, the process called "fracking" involves sending lots of water treated with chemicals down a potential oil or gas well, then pulling it out again and disposing of it in underground injection wells that are deep enough so the injected fluids don't mix with groundwater.  At least, that is the intention.

Drillers have done fracking for many years, and according to a website operated by the U. S. Environmental Protection Agency, Texas has over 52,000 Class II injection wells, which are typically the type used by fracking operations.  But only in the last five to ten years has fracking become a widespread practice near populated areas of North Texas, where the Barnett Shale formation has become the focus of intense exploration and drilling.  In the interests of full disclosure, my father-in-law received some money for mineral rights related to drilling near his former home in Fort Worth, which he no longer owns.  And my sister lives in Cleburne, some 30 miles south of Fort Worth, which has experienced a few earthquakes of its own in recent months.  Cleburne is near a lot of fracking activity and injection wells too.

Suppose there is a connection between shoving lots of water underground and triggering earthquakes:  what then?  Is this a matter of engineering ethics concern?  I would certainly think so.

The parties most directly involved are (1) the oil and gas drillers, (2) the people living in areas subject to these strange earthquakes, (3) the organizations paying for and benefiting from the drilling, (4) local, state, and federal regulatory authorities, and (5) the general public, which is not directly affected by the earthquakes, but benefits in some way from increased domestic supplies of fossil fuels, and is possibly harmed by the general increased risk of earthquakes in the future.  But identifying the concerned parties is only the first step.

From a legal point of view, the situation is extremely fuzzy.  Although there have not historically been a lot of Texas earthquakes, there were enough for U. T. Austin geology professor Cliff Frolich and his colleague Scott Davis to write a book about them in 2002.  I have read that book, and the impression I got was that Texas is not under any existential threat from a "big one" like California is due for.  Rather, there are lots of little faults here and there, and every so often one of them gets tense enough to snap, like a third-grade teacher the day before Christmas vacation.  Frolich wrote a report back in 2009 on a cluster of earthquakes near Cleburne, where he confirmed that numerous injection wells had been operating.  After installing a special array of seismographs, he detected even more earthquakes than the standard USGS network did, and in the abstract of the report he stated, "A plausible hypothesis to explain these observations is that injection only triggers earthquakes if injected fluids reach and relieve friction on a suitably oriented, nearby fault that is experiencing regional tectonic stress."  What he's saying in ordinary English is something like this:  Earthquake clusters are like doors that have both a lock and a key.  The lock is the local conditions of stress and orientation that make the fault ready to let go, and the key is the water coming in from the injection wells.  When the key fits in the lock, the door opens and in comes an earthquake.

Seismic data on earthquakes is easy to come by; besides the USGS data, there are other online databases and the information is relatively easy to find and read.  The question of where injection wells are and how much fluid is injected is a harder one to answer, although the Texas Railroad Commission (named that for historical reasons), which is the state regulatory agency for oil and gas drilling, has a database on injection wells that will yield such information to diligent inquiry.  I diligently inquired for about five minutes this morning and turned up a bunch of wells across Eagle Mountain Lake from Azle, but nothing right in the town.  But maybe Azle sits on the lock, and the key flowed under the lake from the other side, so to speak.

I'm no geologist, or lawyer either.  If Azaleans (or whatever you call citizens of Azle) get tired of being shaken awake at 2 A. M. and organize a class-action lawsuit, their lawyers would have a rocky road to travel (so to speak) in order to prove to the satisfaction of a civil-trial jury that such-and-such injection wells directly caused so-and-so earthquake.  The only similar legal issue I can think of would be a lawsuit concerning structural damage caused by dynamiting for quarries and similar purposes.  In those types of cases, all the plaintiff has to show is that at Time A before the blast, the damage wasn't there, and right afterward at Time B it was, and usually it's easy to show that because the physics of shock propagation is pretty well known and hard to argue against in court. 

That is far from the case for these earthquake clusters.  In defense of their practices, fracking drillers state correctly that they have been doing fracking for many years in Texas and elsewhere, and nobody much noticed any earthquake clusters back then.  My own guess is that they just happened to be fooling around with keys where there weren't any locks.  But now that the fracking activity is so visible near populated areas such as the Dallas-Fort Worth area, people have begun to notice the clusters and start putting two and two together. 

So far, no one has been seriously injured or killed in a recent Texas earthquake cluster in areas where injection-wells are suspected as the cause.  As long as the damage remains minor, the general good will enjoyed by the oil and gas industry in Texas will probably continue, especially if they keep spreading around those royalty payments of a thousand dollars or so to anyone in the neighborhood of an active well.  But if we get a seriously bad earthquake that results in injuries or deaths near a place where injection wells are operating, watch for the legal and regulatory picture to change fast.  For my sister's sake, as well as the fracking industry, I hope that never happens.

Sources:  The book Texas Earthquakes by Cliff Frolich and Scott Davis was published in 2002 by the University of Texas Press.  An abstract of Prof. Frolich's report on the Cleburne earthquake cluster is accessible at http://www.pnas.org/content/early/2012/07/30/1207728109.abstract.  The EPA website with statistics on Class II injection wells can be found at

http://water.epa.gov/type/groundwater/uic/wells.cfm. I referred to articles in a Russian news website on the Azle earthquakes, published at

http://rt.com/usa/texas-fracking-earthquakes-azle-445/

and data on the Azle earthquakes from the earthquake website

http://earthquaketrack.com/us-tx-azle/recent.  I also referred to the Wikipedia article on Azle.