There was a fourth headline that came out almost immediately after a quake (and before the US Geological Survey website had been updated with the pertinent information), but we didn’t need to be alerted about that one – my husband, my Mother-in-law, and I were in the middle of it. This fourth quake, the biggest temblor ever experienced in Oklahoma measuring at 5.8 on the Richter Scale, occurred September 3, 2016 over Labor Day weekend when we were supposed to be having a jovial,relaxing, light-hearted visit with family. Had the epicenter been located as close as the other three, there would have been severe damage to my Mother-in-law’s house. (This one’s epicenter was north near Pawnee, Oklahoma, where unfortunately, our oldest nephew lives – but he and his wife sustained no damage to their home.)
Potential drawbacks to increasing seimicity in this area is related to being the Oil Pipeline Crossroads of the World – there are huge petrochemical storage facilities in the area in the form of giant, welded tanks. The closest image I’ve seen in The Jerusalem Post’s photo collection that comes close to matching these colossal engineering feats is the large ammonia tank in the Haifa bay area that is reputedly to be emptied, shut down, and relocated elsewhere. Just like in Haifa, if some large-scale disaster (other than a tornado) befell the community, these enormous storage tanks would be destroyed, creating an ecological disaster. Or, if the town were involved in a military attack, bombs or missiles would create an explosive disaster far beyond the scope of the human imagination. Some of these storage tanks are very old, while others sprang-up rapidly since the drilling boom of the early 2000’s. Local geologists have been warning the state that if earthquakes greater than 5.6-6.2 were to occur having an epicenter near the “storage tank farms” that these tanks could not stand the strain and would rupture.
The one earthquake which caused the most damage to my Mother-in-law’s house occurred in early November, 2016, and was only 5.0 on the Richter scale, but its epicenter was very close to my Mother-in-law’s house (1/2 mile or 0.8 km – between her house the the old Main Street of Cushing). Since then, we have been undertaking small family” do-it-yourself” projects to fix the damage. The worst thing that happened was a large double-paned plate glass window in her formal living room cracked and broke, but only the inner pane was shattered into big glass shards.
The most dangerous thing that happened was a large 75 to 100 pound (i.e., 35 to 45 kg) bathroom mirror came crashing down onto the bathroom vanity, but it miraculously, it didn’t break. My husband and I hung the mirror back on the wall in one of the most arduous, labor-intensive repair jobs we’ve had to do in a long time. Let me say that we didn’t have problems because we were weak – it is just the mirror was so large, heavy, and cumbersome that it had the tendency to smash our fingers between it and the vanity’s backsplash. Because the earthquakes in the area are getting more and more intense, we know it is a matter of time until it falls down again in another quake. So, we are currently building an oak frame for the mirror to better anchor it to the wall so it doesn’t come crashing down on anybody’s head.
Then, there were the little things which were displaced in the earthquake (that the guys in the family couldn’t care less about) -- like dishware, goblets, sugar bowls, etc., in my Mother-in-law’s china cabinet that got dislodged toward the front of its glass door. So, if you opened the china cabinet door to re-arrange everything displaced, all of her elegant, now antique dinnerware would have tumbled out and broken on the floor. But, the guys in the family figured out how to tilt back the hutch on the cabinet to get everything to slide back onto a better, more stable position on the cabinet’s shelves, so that wasn’t too big of a deal. Then, we keep finding little figurines in not-too-frequently-visited corners of the house that fell off of their previous perches and were pulverized.
A lot of people may be wondering, “How come Oklahoma is suddenly getting a rash of earthquakes lately?” Does it have anything to do with hydraulic “fracking” that is popular in the oil production industry? Or is it related to waste salt-water injection wells? Or, does it have anything to do with the dreaded New Madrid Fault near the central states lying on the Mississippi River?”
Earthquakes in Oklahoma really haven’t just become a new phenomenon overnight – for a long-time, our state has held the dubious title of the small earthquake capital of any of the 50 states. But these earthquakes have been “sub-threshold” where humans do not detect anything is going on. The quakes showed up on seismometers and seismographs though, and most (but not all quakes) over 4.0 are the threshold where most people feel the quaking. The number of earthquakes is increasing somewhat, but the intensity of the quakes has gotten stronger over time where Oklahoma citizens are now feeling them.
I remember in the early 1990’s, I working in a multi-story building near the main airport at Tulsa, OK. Some of the secretaries were complaining that from time to time, the building would start swerving like a tree in a heavy wind. Although at the times this had occurred, there weren’t any heavy winds in the area. (We do get some pretty impressive wind events besides tornados, though! But these instances weren’t related to the wind.) After it happened the second time, I decided to get on the phone with the nearest USGS seismograph office and check to see if there had been a sub-threshold earthquake. And, that was usually the cause of our building sort of wobbling around in the sky like somebody who has had few too many alcoholic beverages. Unfortunately, explaining this to a number of people in the office had the opposite effect of the reassurance I was trying to give everybody! Nobody wanted to hear that this was a natural, common occurrence and they didn’t want to hear about the fascinating geologic features which lay beneath their feet that were the sources of these mini-quakes.
In addition to all the oil that has been found in Oklahoma, we have a diverse structural geological aspect of the science. There are very ancient mountain ranges with complex faulting buried under many sedimentary rock layers which sort of “pinch out” to finer beds the closer you get to the mountains. Then, there are the ancient mountain ranges that we see at the surface. Many people can relate to the Ozark mountains in Missouri and Arkansas – Oklahoma has some concurrent structures created at the time of the Ozark uplift – the Ouachita Mountains, the Arbuckle Mountains, the Wichita Mountains, and the Quartzite Mountains. These mountains aren’t very tall because over time, their less-resistant rocks have been weathered away from the tops usually leaving behind a somewhat smoothed-over, rounded, igneous rock core that had been complexly folded and faulted. The sediment that has been carried away has contributed to the sedimentary rock layers which sort of lap up the sides of the remnant cores.
The best way I can explain this is to imagine you’re sitting at a slick-topped kitchen table that is covered by a table cloth. If somebody (say, an obnoxious grandson who may be a budding geologist, but for now, he can’t do anything but cause trouble at the dinner table) starts pushing horizontally on the table cloth at the edge of the table. Then, he keeps pushing on the cloth towards the center of the table, with the slick table top giving a non-resistant surface over which the soft table cloth horizontally and gently slides, resulting in the table cloth bunching up into a number of folds (and the grandma starting to yell that the grandson is messing up her table setting!). This is what happened to the ancient rock layers in the mountain building events. Now say, an equally obnoxious granddaughter with a “really great idea to fix it” comes in with the large sheep-shearing clippers and tries to even out the table cloth by shaving off the tops of the folds -- this is like what happened to wear down the tops of the mountains until we only see the stubble or roots of the ancient folded rocks.
So, instead of ill-mannered grandkids pushing Grandma’s table cloth to make mini-mountains on the kitchen table, what was the event that triggered building of these mountains? A plume of hot magma came up from the mantle of the earth, causing the lighter crustal rock to split and rift apart. The overall movement gradually pushed up these mountain ranges in all the land margins distant from the original magma-produced rift. In the central US, this created the New Madrid fault zone -- which is actually a faulted-rift valley left over from an event which broke up a proto-continental. Whenever this rift-valley formation occurs, the cracks usually start out in a 3-pointed stellate pattern, with one or two of the cracks developing into deep chasms dramatically splitting the continental crust. Then, there is the third crack where a rifting process begins, but it isn’t as dramatic or successful as the other one or two rifts. The New Madrid Rift Valley, as well as the Jordan River Valley in Israel that extends from Galilee to the Red Sea, are examples of two such not-so-successful cracks left over from splitting continental crustal rocks.
“Wait a minute!”, you are thinking. “Does this mean the Jordan Valley Rift Zone has the same potential to create nasty seismic events just like the New Madrid fault in the US is predicted to do?” The answer is -- yes. I know this isn’t going to make a lot of people feel any better about the situation, but if you are a student of Bible prophecy you will see great earthquakes for the Holy Land are unfortuantely predicted. I wish I had better news for you. The last earthquake I know of which was felt in Israel (also reported in The Jerusalem Post) had its epicenter in the near the lower, eastern Sinai peninsula, which is on the edge of the Jordan Rift Valley.
Now that I’ve wrecked everybody’s day in the Middle East, we shall return to Oklahoma’s increasing magnitude of earthquakes. Do the practices used in hydraulic fracking in Oklahoma’s oil production efforts cause more earthquakes which can be felt? This has been highly controversial but the experts at the main universities in Oklahoma are currently saying no.
When fracking is employed, high pressure fluids with additives which may increase rock porosity and decrease hydrodynamic resistance are pumped into the hydrocarbon bearing beds . As expected, fluid comes out, but it isn’t all oil – it is usually a mix of hydrocarbons and salt water from ancient oceans that were the usual environments where most of today’s sedimentary rocks were produced. If you produced 16 gallons of fluid and you separated the oil and water, you usually see 1 gallon of oil and 15 gallons of waste salt water that has been contaminated usually by hydrocarbons, and/or possibly heavy metals .
This wastewater from the fracking process isn’t the healthiest stuff to have lying around, and somebody decided a long time ago to start re-injecting the water back into the sedimentary rock layers. And, they happen to choose what were deep layers of sedimentary rock lying on the ancient, faulted mountain range cores (especially the consolidated sediments from the Arbuckle Range, the small mountain range which is kind of in the middle of the other ancient Oklahoman mountain ranges). The fluid would seek the “path of least resistance” and tend to leave the sedimentary rock to snugly work into the ancient faults, thus lubricating these ground-up and smoothed-over surfaces that once long ago slid against each other, creating Oklahoma’s rash of human detected earthquakes.
So, do the salt water injection wells cause problems? The answer is yes, but if the practice were stopped, earthquakes would still occur. Why? Because now a negative pressure gradient (a vacuum, or as Ross Perot used to like to say, “that giant sucking sound”) is created in the rock strata mechanically pulling fluids from sedimentary rocks into the ancient fault zones. If waste salt water injection are performed properly though, there shouldn’t be as much of a problem, and the state has recently released new guidelines on salt water disposal. The last I read, they said small earthquakes related to injection wells is now only occurring “in the northwestern part of the state”. Apparently there is a whole different subterranean geologic scenario besides faulting from ancient mountain ranges in that part of the state where I currently live that the experts want to study to see if an answer can be found to prevent further earthquakes.
In writing about some of the challenges the oil industry of my state has faced in the past, I am hoping to initiate academic thought and discussion about some of the issues which may arise as Israel develops its own oil and gas industry. Oklahoma is nowhere near the most abundant producer of oil and gas in the US – that honor still belongs to our illustrious neighbor, the state of Texas. But both Texas and Oklahoma have a great number of well-trained earth scientists and petroleum engineers who have evaluated the effects various practices in the western oil drilling industry can create in the long-term. Once again, the dramatic tightrope act of “production companies anxious to begin producing cheaply using traditional methods” vs. “expert scientists who have a better idea of what the low-cost practices do to the earth” is in play, much to the awe of the laypeople who are spectators who may not fully understand the all forces which are acted out.