WHATS IN THIS BLOG:
• Earthquakes in my Iphone.
• Fracking doesn’t cause earthquakes.
• Largest earthquake in Oklahoma was missed by forecasters.
• Earthquakes are declining with time in Oklahoma.
• What are the chances of a big one?
• What to do if you are in the path of the big one.
THREE TIMES MY IPHONE WHISTLED AT ME LAST NITE. This means three earthquakes on my earthquake app. Here is what it told me:
A 3.7 earthquake occurred close to Waynoka, Oklahoma.
A 3.3 earthquake occurred close to Harper, Kansas.
A 3.5 earthquake occurred close to Gardnerville, Nevada.
The app tells me earthquakes of magnitude 3-4 can be felt by people but little damage.
The quakes in northern Oklahoma and southern Kansas have one thing in common: they occurred in an area that has been heavily drilled to extract oil from the Mississippi limestone.
A FRIEND SAID LAST WEEK THAT FRACKING CAUSES EARTHQUAKES. Wait, I said….. this is not true. In the Mississippi lime of northern Oklahoma, for example, the earthquakes often originate from 3 miles depth (16,000 ft) and this is much deeper than where the fracking was done at 3,000 – 6,000 ft at the bottom of a well.
In fact, fracking in Oklahoma is done in shale or limestone or sandstone which lies above the granite basement, while most of the earthquakes originate in this basement rock (see first image).
IF FRACS ARE NOT THE CAUSE OF EARTHQUAKES, WHAT IS? The short answer is injection wells, which are commonly called disposal wells. This is where the salty water produced along with oil or gas is disposed of. In Oklahoma, this so-called produced water, along with a small amount of frac water that comes back from each well, is injected into the Arbuckle limestone that sits on top of the granite basement.
Since 2009 when the new technology from shale gas was adapted to the oil-producing Mississippi lime, the number of drilling rigs and oil wells rose dramatically (see image) right along with the price of oil…. up to $100 a barrel. In sync with this, the number of disposal wells increased — about one disposal well is needed for every 10 producing wells. However, as the image shows, the price of oil crashed in 2014 to less than $30 per barrel, and drilling virtually stopped. But note…. the earthquakes didn’t stop!
Over the years the Arbuckle limestone started filling up with salty produced water. As this water spread out horizontally, some of it leaked down into big geologic faults in the granite basement. When this happens, the water acts like a lever and weakens the grip which the earth stresses have on the fault, and the fault slips which causes an earthquake.
Over time in California, faults slip due to gradual movements of the earth’s crust. But in Oklahoma, faults slip because of the produced water injected in disposal wells. This is called induced seismic activity.
WHEN THE LARGEST-EVER OKLAHOMA EARTHQUAKE occurred in September 2016 (magnitude 5.8), near the town of Pawnee, the first thing the
regulators did was to turn off the nearby injection wells. About 6 months before this quake, in an irony of fate, regulators had requested oil and gas companies to reduce injection rates in disposal wells inside the boundary line of the image, but the Pawnee quake occurred just outside the regulated area….. the regulators just missed it!
The earthquakes in Oklahoma reached their peak in 2015 when over 900 were recorded. This was six times more than in California. By 2017 the number of quakes in Oklahoma had decreased gradually (see bar chart).
WHAT ARE THE CHANCES OF A BIG ONE?
The map below shows that for 2017 the chance of damage is 5-10% in the red patch north of Oklahoma City. This patch is larger than the red patch in California!
If you are in the path of a big one, do the following to protect yourself from falling objects: (1) drop to the ground; (2) crawl under a desk to cover your head and neck; and (3) hold on to any sturdy cover.
TAKEAWAY: ARE FRACS CAUSING EARTHQUAKES? THE ANSWER IS NO — NOT DIRECTLY. But fracking wells increases the produced water, which comes out with oil or gas, and the produced water causes earthquakes when it is reinjected in disposal wells. So there is an indirect connection.
How much produced water is disposed of? In Oklahoma, 1530 million barrels of produced water in 2014 were injected into disposal wells. That’s close to 1.5 billion barrels in one year. This is equivalent to approximately 13,000 football stadiums each filled to 10 ft of water over the grassed area. Wow! To read more, click here.
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The Gray Nomad
Think well, and help someone to hope.
Lord, make me to know my end, and to appreciate the measure of my days; let me know and realize how frail I am – how transient is my stay here.
[Book of Psalms, chapter 39, Amplified Bible].