LK: Our inability to make decisions and take into account the future makes a lot of our choices very risky.
MG: Hi, you’re listening to the Fairewinds Energy Education podcast hosted by the Fairewinds crew. I’m Maggie Gundersen, and welcome to the show. Recently, we did a show about seismology and we had geologist Dr. Les Kanat on with us and Chief Engineer Arnie Gundersen. And we’ve had so many questions from our listening audience that we wanted to bring you one more portion of our discussion. Some of the questions people have asked have been about the human aspect of seismic issues. For example, can humans in our activity – bulldozers, building things, going down to bedrock, and fracking – can they cause earthquakes. So I’m opening the floor to Les and Arnie, and they’re going to talk to you about what this issue is and what does it mean to nuclear power plants.
LK: We have really good evidence that human activity has been the cause of seismic events. One recent example was in 2011, the National Football League had a playoff game between the Seattle Seahawks and the New Orleans Saints. And one of the players, whose name is Lynch, ran a 67-yard touchdown during the playoff game that basically was the winning touchdown for that game. The fans, all 66,000 fans – were jumping so vigorously that it registered a magnitude 1.5 earthquake on the seismometers not too far away. So that’s one way in which we can cause earthquakes. There are other, more devastating examples of that. For example, on 9-11, when the first plane impacted the first tower, that event shook the ground enough that 34 kilometers north of the World Trade Center – about 20 miles north – that impact registered. The second impact also registered on the seismometers, as did the collapse of the buildings. So, for example, the first collapse registered as a 2.1 magnitude event. That was 34 kilometers north of where the seismometer was – 34 kilometers north of the building itself. The second tower, when it collapsed, was equivalent to a 2.3. So human create seismic events by jumping around, by destruction events like taking down buildings. But also we create earthquakes when we really mean to make the world a safer place. So out in the Rocky Mountain arsenal in the 1960’s, we used to inject millions of gallons of contaminated liquids into deep-well injection sites. We figured that by taking contaminated liquids, putting them deep into the earth – meaning miles – that we would be safe and not have to worry about the contaminants. So when we look at a graph that looks at the relationship between the number of gallons – an order of millions of gallons a month that we’re pumping down into the ground, and the earthquake frequency in that area, 1962 and 1963 were averaging about 6 to 8 million gallons a month. And the number of seismic events increased significantly. For the year 1963, we stopped injecting fluids; seismicity ceased. And then back in ’65, we started injecting 8 to 10 million gallons a month, and the number of earthquakes rose precipitously. So we’ve known for a long time that by injecting water into the ground, we can increase seismic events. That recognition had the idea that we should inject liquids along the San Andreas Fault so we could trigger these small events and therefore miss the big one. So for several years, maybe even a decade, we injected lots of water into the ground and we did trigger lots of small events. But it wasn’t enough to offset any major seismic event, so we stopped doing that. Since we’ve been drilling oil (sic) we’ve always fracked the wells, we would drill a well to try and extract oil, the rocks weren’t permeable enough, so we would fracture the well, either by explosions, dropping explosives down the well, or by putting a lot of water pressure down the well to hydrofracture the well. So we’ve been doing this for a long time. And only recently, we’ve started fracking the rocks to extract gases. So it’s not surprising that we see lots of seismic activities around places where we’re fracking.
AG: (5:15) Yeah, I guess I could add one more to that list. There are cases where dams have been built and the combination of the weight of the water that wasn’t there before and the fact that that waters moves into cracks in the ground have caused earthquakes as well. Whatever humans do on the surface seems to get translated down below that.
LK: If we look at just the earthquakes in Oklahoma, as we’ve started fracking, in 2009, basically, and prior to that, there were very few earthquakes and all below magnitude 3. In 2010, we had about a thousand earthquakes. That kept increasing. In 2013, we had about 3,000 earthquakes. 2015 is about 6,000 earthquakes every year. So the number of earthquakes – and now we’re even getting magnitude 3 earthquakes in Oklahoma – large earthquakes – because we keep injecting water to fracture the rocks, to break them apart. And again, when rocks break, that’s an earthquake. So we are inducing earthquakes in order to extract gases. Because by fracturing the rock, we create avenues for gases to escape and for us to capture them.
AG: I have a question, Les. Is the water acting as a lubricant? Like putting oil on the surface and allowing the rocks to slide by each other?
LK: With fracking, there are a couple of things going on. That would be one of the aspects. But with fracking, the water is also corrosive, to help dissolve some of the rocks. There are lots of chemicals that we put into the fracking waters. And we also inject sediment – sand-sized grains – to be able to keep those fractures open. So it’s not just clear water we’re pumping down there.
AG: I can’t believe that we actually tried to pump fluid into the San Andreas Fault. That’s like trying to slide a plate out from underneath a pit bull or something like that, while it’s sleeping. That doesn’t seem to me to be a very prudent way of helping the San Andreas Fault relieve its faults.
LK: Well, if you would have told the geologists that a decade ago, you could have saved us a lot of money.
AG: We’ve had one other question by people, and that’s could the earthquake in Japan have been caused by a nuclear weapon. And in fact, how do we detect nuclear weapons anywhere. It turns out that the shape of a pulse from a nuclear weapon is different than the shape of a pulse from a normal earthquake. So if you’re a geologist and you see a spike on your charts, you can tell whether it’s an explosion or whether it’s a natural phenomenon.
LK: When you say the shape of the pulse, I think you’re meaning the signature that’s recorded by the seismometers. They are distinct between earthquakes – even types of earthquakes. Are they results of extension or compression? Are they results of explosions? So we know when and where and how big earthquakes are and the same is true for all underground nuclear tests. So during the period when we had a lot of underground nuclear testing around the world, seismologists were in high demand because we wanted to know who is testing and where they’re testing and how big these events are. Because a nuclear weapon releases a certain amount of energy and because earthquakes release a certain amount of energy, we can relate nuclear events to what would be an equivalent magnitude on the Richter scale. It’s all about energy and time. And I think what we don’t realize as a society is that although geologists’ greatest contribution to society is the recognition of deep time – that is, that the earth is the result of billions of years of evolution – that’s a pretty big idea to grasp – we still don’t make decisions thinking about the long term. And we think about what might happen tomorrow or next year or maybe five years at the most. So our inability to make decisions that take into account the future makes a lot of our choices very risky. I think Yogi Berra said it right, that it’s really hard to make predictions, especially about the future.
MG: I agree with you, Les. That’s really pertinent to nuclear power. Because at Fukushima Daiichi, there were these stone monuments all along the coast that said “Do not build below this level” because of tsunamis. These stone pillars were more than 1,000 years old and they forewarned of the issue of tsunamis along the Japan coastline. So we forget how time is. We forget that time is eons.
LK: Or we think it hasn’t happened in 1,000 years; therefore, I’m safe. We can do this.
MG: On that note, we’ll close this session and we’ll keep you informed. Thanks for listening.
