Okay, I know this is a science fiction/nerdist website, but once in awhile I feel the need to express some notion or thought from my professional life, i.e. geoscience. I feel this need because A: occasionally I have an idea that I can’t really put forth in a peer reviewed journal because I’m not an academic and don’t really want to be, and B: Once in a blue-moon as I read peer-reviewed journals I see an idea I’ve had and think, “Hey, I had that idea! If only I had the skills, facilities, and where-with-all to propose, test, and propound that hypothesis in an acceptable form so that I could, I don’t know, be cool and junk.” It’s really just a version of that annoying thing people do when some new device or advance comes out and they say, “I totally thought of that before!” and if it wasn’t for their lack of engineering skills and business acumen then they would be inventing the I-phone or The Sims or Crystal Pepsi. Anyway, this isn’t really one of those. It’s not even original. I just noticed something odd when I was looking through earthquake logs… because that’s something I do…
Background: Oklahoma City, November 5th 2011, 10:50PM: I had just gotten home from work after a long day of differential equations and slinging beer. We lived in a fine little house in a wonderful enclave called Nichols Hills, a place famous for having more cops and billionaires per capita than anywhere else in America. Life was good. I sat down at the kitchen counter to read the recent edition of Time Magazine when the wiener dog came shrieking through the house. This wasn’t unusual. The wiener dog does that from time to time. This time however it was followed by the house shaking in an alarming fashion. Pictures swayed, cabinets opened, piles of books that I seem compelled to create fell over. It felt like it went on forever, the whole world was growling. Then it ended. I went to my desk and withdrew a list, checked off the box beside, “survive earthquake.” I was a happy man. I had just survived the strongest earthquake to hit Oklahoma in recorded time.
Fracking: In the days, weeks and months that followed their began a debate on whether this earthquake had been caused by fracking, the process of injecting salt water and a slurry of other chemicals into the ground at such prodigious pressures that the basement rocks fracture, giving up the natural gas locked inside them. People that hate Mother Nature said, “NOOOOO!” People that hate hot showers, cars, abundant food and America said, “YESSSSS!” Initially I was with the Nature Haters. No, we tiny humans cannot cause a 5.6 magnitude earthquake. I mean, that has the power of an atomic bomb and we’ve never created one of those, right?
Well I still don’t think we caused the 5.6. Oklahoma has earthquakes on occasion. From 1952 through to 1969 about ten significant earthquakes occurred in central Oklahoma (more if you break out foreshocks and aftershocks). This historic cluster seems to be similar to the above mentioned 5.6 and the 5.2 that occurred a few weeks later. But those are not the only earthquakes. The problem really seems to be that in the 20th century there were about 84 quakes, then in what suggests a directly proportional relationship (suggests only), the quakes increased as the fracking increased. 49 quakes in 2009 and up it goes.
In reality the quake numbers are far greater. In the years since 2009 the actual quake numbers are in the thousands per year, though the vast majority are exceedingly small. So here is where one of my geekier habits comes into play.
I want to introduce you to IRIS, a resource from the Incorporated Research Institutions for Seismology. Oh how I love thee. I go to IRIS every day to see what is shaking where. Just go there and you will see this:
This is an interactive map denoting all recent quake activity, current quakes, magnitude etc. And whats more, you can focus on the region and pull up the last thirty days of activity, and plot the region into a 3-D viewer, FANTASTIC! So I’m doing this and I think, “Why don’t I look at some various types of high activity regions around the world and see what they look like graphically when compared to Oklahoma. Here is what I found:
This is looking north to south at the east coast of Japan, Honshu Island (main island). The compass lines are on the surface, the white lines are the coast of Japan in this area with the pacific extending east from the white line. U is up and D is Down. Each bubble is an earthquake, color is depth, purple is surface down to 33 kilometers, those deepest yellow bubbles are nearly 300 kilometers down. Notice that the quakes “plunge” at an angle with the majority of the quakes between 15 and 70 kilometers where the Pacific Plate is grinding under Eurasian Plate as well as interacting with the Philippine Plate to the south. These earthquakes are shallow and dangerous as we have seen.
Here’s another subduction zone similar to japan on the other side of the pacific. We are looking at the coast of Central America, Honduras to be specific, where the Caribbean Plate is riding over the Cocos Plate. Like Japan, this plate subduction is the cause of intense volcanism, and both areas are famed for their pyroclastic eruptions and classic “cone” stratovolcanoes. Note similarities to the strike of earthquakes, trending down with the plate as it is overridden and sent to the mantle to melt.
This one is a bit hard to see, but I wanted to show one of the most expressive plate boundaries on earth. This is in the Celebes north of Indonesia. Here you can see red quake bubbles, indicating earthquakes nearly 800 km down. This is where the Australian plate is diving under the southern tip of the Eurasian plate. Four plates interact on Indonesia and that is why you get Tsunamis and Krakatoa.
So this is Iceland, specifically Askja, a volcano that has been experiencing swarms of small quakes. Iceland sits on a hotspot where the Eurasian Plate and North American Plate are separating, and it is just chock full of volcanoes. The earthquake swam you see above is essentially an outline of a vast magma chamber, though chamber is a misleading assignation. It isn’t a subterranean lava lake so much as regions of melt, pressure gradient leading to gas expulsion and fissures. The thermal discontinuity, mechanical energy and other phenomenon lead to pent up stress being released, sometimes through fractures releasing old fault tension. Hmm, fracturing releasing tension… Anyway, notice the tight cluster and the similar depth of just a few km down.
this is north central Oklahoma, a place full of fracking and just as important, deep injection waste water wells- places where they get rid of the fracking water by shooting it deep under ground. Note the similar depths and as importantly the, the small size. These are all very small quakes, below 3.0 on the Richter scale.
For me, this is the most intriguing evidence. this is the same map of Oklahoma earthquakes that appears directly above, only viewed at ground level from west to east. Notice that all the earthquakes are nearly perfectly aligned on a minimum depth ceiling and then vary only fractionally in maximum depth, much like a strata of gas bearing rock. Only volcanic magma chambers have similar features and they are more striking for their differences than the similarity. this isn’t a radial glob of activity, but something much less natural.
This is the closest I could come to finding a natural feature similar to Oklahoma. This is the San Adreas Fault in one of it’s less complicated stretches in a similar view to the one above. The ceiling is similar, though less perfect, but the extent is much, much greater. Where as the Oklahoma quakes barely push past a couple of thousand feet, these go down as far as 40,000 and more.
So, does fracking and/or deep waste water disposal cause earthquakes? Probably, but it’s doubtful that it could cause catastrophic tumblers, though one may argue that small shakings could increase the likelihood of catastrophic energy release in nearby faults. Dominoes are funny that way. The 1964 Alaska Earthquake (mag 9.2) caused old faithful in Yellowstone to change its eruption cycle over two thousand miles away. Granted that earthquake was about 10 to the 7 times more powerful than what Oklahoma is seeing, but again- dominoes. Does it matter? Depends on where you are I think. The damage to my house in Oklahoma in 2011 was twelve dollars when the scared dachshund peed on one of the overturned stacks of books. If I were an actuary I wouldn’t worry too much, and that is exactly why I’m NOT an actuary. Actuaries are very much worried about this. The fact that the debate is less heated in the media doesn’t mean that the debate is over. When fracking was first blamed every energy industry group had its puppet geologists out screaming bloody murder that fracking unequivocally can not cause quakes. Other puppets yelled back. Meanwhile science started happening, mostly quietly, mostly ignored. It’s not hard to find USGS sources and their state equivalents now saying that yes, fracking could be causing small earthquakes.
And there you go. If you have any questions on hydraulic fracturing, ask an expert.
What the Frak!?
Thanks for sticking around, and for all the emails asking me to get back to work. I was really touched… and kind of confused.