Half a million earthquakes occur worldwide each year, according to an estimate by the U.S. Geological Survey (USGS). Most are too small to rattle your teacup. But some, like the 2011 quake off the coast of Japan or last year’s disaster in Italy, can level high-rise buildings, knock out power, water and communications, and leave a lifelong legacy of trauma for those unlucky enough to be caught in them.
In the U.S., the focus is on California’s San Andreas Fault, which geologists suggest has a nearly one-in-five chance of causing a major earthquake in the next three decades. But it’s not just the faults we know about that should concern us, says Kathryn Miles, author of Quakeland: On the Road to America's Next Devastating Earthquake. As she explained when National Geographic caught up with her at her home in Portland, Maine, there’s a much larger number of faults we don’t know about—and fracking is only adding to the risks.
When it comes to earthquakes, there is really only one question everyone wants to know: When will the big one hit California?
That’s the question seismologists wish they could answer, too! One of the most shocking and surprising things for me is just how little is actually known about this natural phenomenon. The geophysicists, seismologists, and emergency managers that I spoke with are the first to say, “We just don’t know!”
COURTESY PENGUIN RANDOM HOUSE
What we can say is that it is relatively certain that a major earthquake will happen in California in our lifetime. We don’t know where or when. An earthquake happening east of San Diego out in the desert is going to have hugely different effects than that same earthquake happening in, say, Los Angeles. They’re both possible, both likely, but we just don’t know.
One of the things that’s important to understand about San Andreas is that it’s a fault zone. As laypeople we tend to think about it as this single crack that runs through California and if it cracks enough it’s going to dump the state into the ocean. But that’s not what’s happening here. San Andreas is a huge fault zone, which goes through very different types of geological features. As a result, very different types of earthquakes can happen in different places.
There are other places around the country that are also well overdue for an earthquake. New York City has historically had a moderate earthquake approximately every 100 years. If that is to be trusted, any moment now there will be another one, which will be devastating for that city.
As Charles Richter, inventor of the Richter Scale, famously said, “Only fools, liars and charlatans predict earthquakes.” Why are earthquakes so hard to predict? After all, we have sent rockets into space and plumbed the depths of the ocean.
You’re right: We know far more about distant galaxies than we do about the inner workings of our planet. The problem is that seismologists can’t study an earthquake because they don’t know when or where it’s going to happen. It could happen six miles underground or six miles under the ocean, in which case they can’t even witness it. They can go back and do forensic, post-mortem work. But we still don’t know where most faults lie. We only know where a fault is after an earthquake has occurred. If you look at the last 100 years of major earthquakes in the U.S., they’ve all happened on faults we didn’t even know existed.
Earthquakes are unpredictable and can strike with enough force to bring buildings down. Find out what causes earthquakes, why they're so deadly, and what's being done to help buildings sustain their hits.
Fracking is a relatively new industry. Many people believe that it can cause what are known as induced earthquakes. What’s the scientific consensus?
The scientific consensus is that a practice known as wastewater injection undeniably causes earthquakes when the geological features are conducive. In the fracking process, water and lubricants are injected into the earth to split open the rock, so oil and natural gas can be retrieved. As this happens, wastewater is also retrieved and brought back to the surface.
Different states deal with this in different ways. Some states, like Pennsylvania, favour letting the wastewater settle in aboveground pools, which can cause run-off contamination of drinking supplies. Other states, like Oklahoma, have chosen to re-inject the water into the ground. And what we’re seeing in Oklahoma is that this injection is enough to shift the pressure inside the earth’s core, so that daily earthquakes are happening in communities like Stillwater. As our technology improves, and both our ability and need to extract more resources from the earth increases, our risk of causing earthquakes will also rise exponentially.
In Pennsylvania, where this gas drill operates, wastewater from fracking is stored above ground. In Oklahoma, it's re-injected into the ground, which can lead to earthquakes.
PHOTOGRAPH BY MARK THIESSEN, NATIONAL GEOGRAPHIC CREATIVE
After Fukushima, the idea of storing nuclear waste underground cannot be guaranteed to be safe. Yet President Trump has recently green-lighted new funds for the Yucca Mountain site in Nevada. Is that wise?
The issue with Fukushima was not about underground nuclear storage but it is relevant. The Tohoku earthquake, off the coast of Japan, was a massive, 9.0 earthquake—so big that it shifted the axis of the earth and moved the entire island of Japan some eight centimetres! It also created a series of tsunamis, which swamped the Fukushima nuclear power plant to a degree the designers did not believe was possible.
Here in the U.S., we have nuclear plants that are also potentially vulnerable to earthquakes and tsunamis, above all on the East Coast, like Pilgrim Nuclear, south of Boston, or Indian Point, north of New York City. Both of these have been deemed by the USGS to have an unacceptable level of seismic risk. [Both are scheduled to close in the next few years.]
The Fukushima nuclear power plant in Japan was not prepared for a tsunami caused by the massive 2011 earthquake. Three reactors melted down.
PHOTOGRAPH BY ISSEI KATO, BLOOMBERG, GETTY
Yucca Mountain is meant to address our need to store the huge amounts of nuclear waste that have been accumulating for more than 40 years. Problem number one is getting it out of these plants. We are going to have to somehow truck or train these spent fuel rods from, say, Boston, to a place like Yucca Mountain, in Nevada. On the way it will have to go through multiple earthquake zones, including New Madrid, which is widely considered to be one of the country’s most dangerous earthquake zones.
Yucca Mountain itself has had seismic activity. Ultimately, there’s no great place to put nuclear waste—and there’s no guarantee that where we do put it is going to be safe.
The psychological and emotional effects of an earthquake are especially harrowing. Why is that?
This is a fascinating and newly emerging subfield within psychology, which looks at the effects of natural disasters on both our individual and collective psyches. Whenever you experience significant trauma, you’re going to see a huge increase in PTSD, anxiety, depression, suicide, and even violent behaviours.
What seems to make earthquakes particularly pernicious is the surprise factor. A tornado will usually give people a few minutes, if not longer, to prepare; same thing with hurricanes. But that doesn’t happen with an earthquake. There is nothing but profound surprise. And the idea that the bedrock we walk and sleep upon can somehow become liquid and mobile seems to be really difficult for us to get our heads around.
Psychologists think that there are two things happening. One is a PTSD-type loop where our brain replays the trauma again and again, manifesting itself in dreams or panic attacks during the day. But there also appears to be a physiological effect as well as a psychological one. If your readers have ever been at sea for some time and then get off the ship and try to walk on dry land, they know they will look like drunkards. [Laughs] The reason for this is that the inner ear has habituated itself to the motion of the ship. We think the inner ear does something similar in the case of earthquakes, in an attempt to make sense of this strange, jarring movement.
After the Abruzzo quake in Italy, seven seismologists were actually tried and sentenced to six years in jail for failing to predict the disaster. Wouldn’t a similar threat help improve the prediction skills of American seismologists?
[Laughs] The scientific community was uniform in denouncing that action by the Italian government because, right now, earthquakes are impossible to predict. But the question of culpability is an important one. To what degree do we want to hold anyone responsible? Do we want to hold the local meteorologist responsible if he gets the weather forecast wrong? [Laughs]
What scientists say—and I don’t think this is a dodge on their parts—is, “Predicting earthquakes is the Holy Grail; it’s not going to happen in our lifetime. It may never happen.” What we can do is work on early warning systems, where we can at least give people 30 or 90 seconds to make a few quick decisive moves that could well save your life. We have failed to do that. But Mexico has had one in place for years!
There is some evidence that animals can predict earthquakes. Is there any truth to these theories?
All we know right now is anecdotal information because this is so hard to test for. We don’t know where the next earthquake is going to be so we can’t necessarily set up cameras and observe the animals there. So we have to rely on these anecdotal reports, say, of reptiles coming out of the ground prior to a quake. The one thing that was recorded here in the U.S. recently was that in the seconds before an earthquake in Oklahoma huge flocks of birds took flight. Was that coincidence? Related? We can’t draw that correlation yet.
The 2011 earthquake in Japan lowered the elevation in towns like Ishinomaki and led to frequent flooding.
PHOTOGRAPH BY MICHAEL YAMASHITA, NATIONAL GEOGRAPHIC CREATIVE
One of the fascinating new approaches to prediction is the MyQuake app. Tell us how it works—and why it could be an especially good solution for Third World countries.
The USGS desperately wants to have it funded. The reluctance appears to be from Congress. A consortium of universities, in conjunction with the USGS, has been working on some fascinating tools. One is a dense network of seismographs that feed into a mainframe computer, which can take all the information and within nanoseconds understand that an earthquake is starting.
MyQuake is an app where you can get up to date information on what’s happening around the world. What’s fascinating is that our phones can also serve as seismographs. The same technology that knows which way your phone is facing, and whether it should show us an image in portrait or landscape, registers other kinds of movement. Scientists at UC Berkeley are looking to see if they can crowd source that information so that in places where we don’t have a lot of seismographs or measuring instruments, like New York City or Chicago or developing countries like Nepal, we can use smart phones both to record quakes and to send out early warning notices to people.
You travelled all over the U.S. for your research. Did you return home feeling safer?
I do not feel safer in the sense that I had no idea just how much risk regions of this country face on a daily basis when it comes to seismic hazards. We tend to think of this as a West Coast problem but it’s not! It’s a New York, Memphis, Seattle, or Phoenix problem. Nearly every major urban centre in this country is at risk of a measurable earthquake.
What I do feel safer about is knowing what I can do as an individual. I hope that is a major take-home message for people who read the book. There are so many things we should be doing as individuals, family members, or communities to minimise this risk: simple things from having a go-bag and an emergency plan amongst the family to larger things like building codes.
We know that a major earthquake is going to happen. It’s probably going to knock out our communications lines. Phones aren’t going to work, Wi-Fi is going to go down, first responders are not going to be able to get to people for quite some time. So it is beholden on all of us to make sure we can survive until help can get to us.
This interview was edited for length and clarity.
Header Image: Nearly 300 people died in an earthquake that hit the village of Amatrice, in central Italy, on August 24, 2016. A major fault line runs the length of Italy. PHOTOGRAPH BY MANUEL ROMANO, NURPHOTO, GETTY