What’s Been Learned From Chile, Haiti Earthquakes?
Wednesday, March 3, 2010
What's been learned from the recent earthquakes in Chile and Haiti? And, what do local residents need to do to prepare for the possibility of a large earthquake in our region? We speak to a local geology professor, and a representative from the San Diego County Office of Emergency Services.
MAUREEN CAVANAUGH (Host): I'm Maureen Cavanaugh. You're listening to These Days on KPBS. When you hear about a devastating earthquake across the globe, your first instinct is to feel sorry for the people affected and find out if you can help. But if you're like many San Diegans, your next thought might be a bit more selfish, something along the lines of ‘will it happen here?’ So, we're taking some time this morning to find out how our quake risk compares with the recent devastating earthquakes in Haiti and Chile. And to run down the list, once again, to see if we're as prepared as we can be for the next significant quake. I’d like to welcome my guests. Dr. Pat Abbott is Professor Emeritus of Geology at San Diego State University. And, Dr. Abbott, welcome.
DR. PAT ABBOTT (Professor Emeritus, Geology, San Diego State University): Good morning.
CAVANAUGH: And Yvette Urrea Moe is Public Information Officer for the San Diego County Office of Emergency Services. Yvette, welcome to These Days.
YVETTE URREA MOE (Public Information Officer, San Diego County Office of Emergency Services): Thank you. Good morning.
CAVANAUGH: Now, Dr. Abbott, let’s first start by talking about the most recent quake that occurred in Chile. It was an 8.8. It’s a breathtaking number for us to think about. What more can you tell us about this earthquake?
DR. ABBOTT: Well, we’ve been measuring earthquakes a little over 100 years and this ties for 5th place in terms of 5th largest in a little more than one century. These earthquakes are so overwhelming we can go back to December 2004 in Sumatra, Indonesia for a 9.2 but in the same ballpark. These giant earthquakes, that the good news for us in Southern California, there’s no way we could have one anywhere near that large.
CAVANAUGH: Explain that to us because I think that’s fascinating and I think that’s so – takes – makes us so relieved to hear this. Tell us why.
DR. ABBOTT: Well, these are what we call subduction earthquakes and that is to say that, let’s say, ocean floor then go down tens of miles below the ocean floor is a big, thick slab. You might visualize it like as a mega-piece of a hardboiled eggshell…
DR. ABBOTT: …that literally is pulled underneath the continent edge. And to be pulled beneath the continent requires a tremendous amount of energy because there’s no hole there; you’re pulling it – it must displace other material to pull it in. So when it does build up and release energy, it’s absolutely overwhelming. And for the United States, our 50 states, there’s only 3 of our states that can have ones that large, and they have. One was Alaska in 1964. The other two states vulnerable for ones this large are Oregon and Washington, and they were last hit in January of the year 1700.
CAVANAUGH: So what kind of earthquakes do we get here?
DR. ABBOTT: We get things like – like the Haiti earthquake. The Haiti earthquake, we basically had that. That was a carbon copy of the Loma Prieta earthquake in October of 1989. Now that’s what we call the strike slip fault, which is kind of a horizontal, a side-by-side kind of motion. Ours in 1989 was a 7.0 in the Bay Area; it was a 7.0 there in Haiti. You see, of course, incredible differences in terms of deaths. About 60 people in the Bay Area versus over 200,000 in Haiti, and that has nothing to do with the earthquake. The earthquakes are the same. The difference is building construction styles.
CAVANAUGH: I want to talk more about that but I’d like to go to Yvette. I don’t want to leave this – the idea of this huge earthquake in Chile just yet because I want to talk about the tsunami warning. Now, as it turned out, there was a tsunami along the coast of Chile but nothing that really reached any significance beyond that. But what does San Diego do when it receives a tsunami warning? How does that warning go out?
MOE: Well, in our office, we have a Staff Duty Officer that is available 24 hours a day so immediately when we get that information from the Alaska – West Coast and Alaska Warning Center, well, it goes immediately to our Staff Duty Officer and that person is monitoring the quake and any subsequent actions immediately afterward. So we had somebody who was, you know, through the night listening to all the updates and, not only that but taking that same information and pushing it out to all of our dispatch areas in the county so that they were also aware of the information that was coming through.
CAVANAUGH: Now are there any warnings that go out to small crafts or what does San Diego do, just wait and watch?
MOE: Well, it would really be up to some of the individual like cities and also some of those agencies because in the County of San Diego, we don’t have any shoreline. So it would really be the cities that might take the lead. And San Diego did do that. They had their lifeguards out there talking to people and warning them on the beach, and then I believe the Harbor Police and also the Coast Guard was out there warning some of the boaters.
CAVANAUGH: Dr. Abbott, a lot of the coverage, I know, on the weekend, at least on Saturday, about the Chilean earthquake was about the tsunami warning. And as I say, except along the coast of South America, that tsunami really didn’t manifest itself in any significant way. How do we know what kind of an earthquake is going to cause a major tsunami?
DR. ABBOTT: Well, this was the type of an earthquake, an 8.8 involving a downward movement of the ocean floor, this is the kind that does generate those huge killer tsunami. And from my perspective – We have tsunami warnings and also tsunami advisories. From my perspective, everybody should feel grateful about it. You know, I hear whining about the H1N1 flu, that it didn’t come around and kill everybody. It’s sort of like we are so fortunate to be living at a time when you can be vaccinated, to have advice that a tsunami might be coming, that I don’t understand why people aren’t simply appreciative of it.
CAVANAUGH: Well, I think we are appreciative but I think we’re a bit mystified, too.
DR. ABBOTT: Oh, well, we are, too. And, see, we know an earthquake that large, we know has a tremendous amount of energy and can make one of those overwhelming tsunami. The trick is, how much of the energy from the fault movement actually goes into the water? Now I don’t know exactly why the Chilean one wasn’t as big as we would’ve thought but if I go back to Indonesia in 2005, they had an 8.5 that should’ve generated a large tsunami and what happened there it turns out is, it was in a basin filled with a lot of sand and mud and a lot of the energy basically was used squeezing that sand and mud instead of just going into the water. So the question is, the energy was there; why didn’t more of it go into the water? And I don’t know the answer to that yet.
CAVANAUGH: Now based on the geology here in Southern California, as you’ve explained to us, we could – it’s highly unlikely that we ever get an earthquake that is as strong as an 8.8. But what do you think – how strong an earthquake could we get?
DR. ABBOTT: The most reasonable one to expect for us within San Diego would be something in the low sixes. Our Rose Canyon Fault that runs along Interstate 5, that moved in Long Beach in 1933 in a 6.4 magnitude earthquake. That’s the northern end of the fault. The southern end passes through San Diego. So it’s only reasonable to expect that. That’s – Rose Canyon Fault could go up to something as high as a magnitude 7 but our buildings would not perform the way they did in Haiti, they would perform more like what we saw up in the San Francisco Bay Area and, hopefully, even better than that because Californians been very, very good about changing building codes and enacting new laws after we have a damaging earthquake to try to have the worst things that happen during an event not occur again in the future.
CAVANAUGH: We’re talking about earthquakes and the earthquakes that we’ve heard about in Haiti and Chile and whether or not we might experience something like that here. We found out not Chile but, yes, Haiti, and it’s all about building codes. My guest is – guests are Dr. Pat Abbott and Yvette Urrea Moe. And, Yvette – In fact, I’d like to ask both of you before we leave Chile. We’ve heard an awful lot about the fact that building codes came to the rescue in Chile. They had this devastating earthquake and we’re hearing more and more about casualties, especially in the smaller cities. But in the major city, they got off pretty well because of building codes. Is this your understanding as well, Yvette?
MOE: Yes, but I’m really not the expert on the building codes. I’ll leave that to Dr. Abbott.
DR. ABBOTT: Well, on these – You know, of course we have a world class testing facility here, UCSD, right by Miramar Air Station…
DR. ABBOTT: …where they test buildings. But for these events where you get up to like 8.8, these things are so horrendous that a lot of the building codes and things we do are based on theory. And if there’s any good that comes out of an earthquake of this size, it will be in Chile now to go and look at some buildings that were thought to have been earthquake-proof to see why they weren’t. And that would be the only good thing that can come out of an event like that.
CAVANAUGH: That’s what we’ve done here in California through the years, right?
DR. ABBOTT: Yes, we have but we haven’t done it with an earthquake that large. So in other words, the – when you only – The Richter scale, the numbers we use are so – they’re very misleading. You know, you go 6, 7, 8, 9, it doesn’t sound like it’s changing much. But every one of those is going up 30 to 40 times in energy release and so we’re just not used to having modern buildings tested by an earthquake that large. And so the silver lining in a horrible tragedy is, hopefully, we’ll learn some things that we can use and apply to building codes around the world so others don’t suffer what – some of the things we see happening in Concepción and other parts of Chile.
CAVANAUGH: Now let’s get to the Haiti comparison that you’ve made and I want to go over that a little bit more, Dr. Abbott, because that’s really very striking, the similarity between the earthquake they just had in Haiti and the one that we had here, the Loma Prieta. Tell us a little bit more about that.
DR. ABBOTT: Well, they’re both what, well, horizontal movement faults and then the faults have a bit of a bend in them so there’s also a little bit of an upward thrust as well. Now, interestingly enough, if we go back in history in Haiti they had basically – Port-au-Prince was basically destroyed in 1751, rebuilt, destroyed again in 1770. At that time, they were under the thumb of France and the French, at that time, said no more buildings with masonry, we’re going to build with wood only. Haiti gains independence in 1804. As the time went on, they’ve forgotten that, and it was the masonry buildings that did them in, poorly formed, badly made concrete, or big bricks made out of bad concrete. Masonry is – it’s strong at a moment but it does not handle – it’s too brittle. It does not handle movements or shaking, and it collapses. Now for us in the Bay Area with the identical earthquake, what is our construction material? It’s primarily one of two things: wood in homes and steel in larger buildings. And if we have bricks or things around, they are adornment. You know, they are not – they’re not things that are holding up the building, so we don’t rely on masonry for the strength of buildings. And that the huge difference, having materials that can give with the earthquake waves, roll with them like wood and steel, as opposed to using these concrete or things there’s only one of two choices, they stand or they fall.
CAVANAUGH: And when you say the two earthquakes were similar, the Loma Prieta and the one in Haiti, I mean, they were strikingly similar except for the death toll.
DR. ABBOTT: The death – well, yes, yes. And the death toll, well, there’s a little saying we always use. We say, earthquakes don’t kill, buildings do. So there’s the same earthquake and then we see that horrendous difference in death and destruction because of building styles.
CAVANAUGH: Now I’m wondering what – do we – We learned things from the Loma Prieta quake, didn’t we?
DR. ABBOTT: Oh, most definitely. We always do. They allow us to focus on things more. I mean, most horrific image from the Loma Prieta earthquake was the collapse of that double-decker portion of Interstate 880. Now, all the double-decker portion didn’t collapse. The only parts that did collapse – the parts that were built on sand or hard rock did not. The parts that collapsed were the ones that were built on soft bay mud. I wouldn’t say it was a brand new lesson but it was a horrible reminder of things that we already knew and that you can’t use the same code, building code, for the same kinds of foundation materials. You must make adjustments when you go out on weaker materials, materials that will resonate and, you know, amplify the seismic energy.
CAVANAUGH: Now, Yvette, as a public information officer for the San Diego County Office of Emergency Services, you must hear from people after earthquakes. You know, they’re a little bit more nervous than they would be before. How do we – just remind us, how do we prepare for an earthquake situation here in San Diego?
MOE: Well, the main thing we tell people to do is—and this is something that they can use for any disaster including a wildfire, anything—is to have an emergency supply kit at home. That’s something that you can do to prepare now and you want to make sure you have enough water and food and first aid supplies to last you at least three days, a minimum of three days, and five days is even better. I can go into more detail about that but we also tell people to have a plan. And that means sitting down with your family, making sure that everybody knows what they’re going to do if something happens because you may be at home when a disaster happens and you may all be at, you know, running your life in different areas, at school, at work, and you may not be together. So you want to make sure that you have a way to get back together, you have a way to contact each other, and we also tell people that they’re – you know, they can walk around their house and do a home hazard hunt and just try to find any potential hazards and fix them.
CAVANAUGH: And what kind of information and resources are available from the County Office of Emergency Services that people might want to get?
MOE: Well, we try to make things really easy so we have a website which is www.readysandiego.org and you can go there and you can download our family disaster plan and survival guide. It tells you everything that, you know, I could tell you here today and you wouldn’t have to take notes. Pretty much it just walks you through what you need to do and, again, you know, like the home emergency supply kit, this is information that you could use for any disaster. If we had a wildfire, a lot of this is just, you know, you can just use it for anything.
CAVANAUGH: Yeah, for any emergency…
CAVANAUGH: …right. Dr. Abbott, I’m wondering, are geologists still trying to figure out how to predict earthquakes? Is that still a major thrust of research?
DR. ABBOTT: Well, it’s something that people are still trying to figure out but is it a major thrust? The failures are so overwhelming. We have spent tens of millions of dollars to try to do these things so far with a total zero in terms of results. It strikes me that the best thing to do is to just assume, at least the way it looks is that the earthquakes are not predictable in short term. And even if they were, if you have badly built buildings, what good does it do to know in advance. In other words, I’d rather see more research, more money going into making buildings earthquake-proof. So, I mean, what I would like would be have it something like when a rainstorm’s coming in, you already know your house is not going to leak. Well, why not have our houses, our buildings stand up in an earthquake so that we don’t have to worry about them so much because predictions, short term prediction’s not coming so getting ready – I mean, Yvette’s describing the things you can personally do but there are other things with building codes and all that are beyond what us ordinary citizens are going to do and we need to address those.
CAVANAUGH: Here in San Diego, we really have a unique tool to test building codes and other earthquake – to see if things are earthquake-proof. It’s that – what do they call it? The shake table at UCSD?
DR. ABBOTT: Yes, and it’s very visible right now when you’re driving along Interstate 15, you know, there’s Miramar Marine Air Station on the west side but on the east side they’re testing right now one of those giant windmills, electric power generating windmills, so you can see the site very easily. But it’s a huge, giant shake table and they can put structures on it, you know, wire it and connect it to gather all kinds of data about how different parts perform during a shake. And I’m a huge admirer of this. To me, the more of that kind of research, the more of that kind of knowledge we get, they’re applicable not only for California but around the whole world.
CAVANAUGH: So they’re testing now whether or not a windmill would withstand an earthquake?
DR. ABBOTT: Yes. I mean, as we see those windmill farms like…
CAVANAUGH: Right. Right.
DR. ABBOTT: …we drive out Interstate 8 over the mountains and you see those huge, huge things. Well, how – if we’re going to be building more and more of these things with time, we need to know how will they perform in an earthquake? Again, we – the engineers do a good job doing it with theory but there’s nothing like having a good old physical test to see, did all theory work or is there something that needs to be, you know, reconsidered and changed a bit?
CAVANAUGH: And, you know, as I said, you know, we have – it’s only the beginning of March, we’ve had two devastating earthquakes so far, and I wonder, is there anything to the idea that there are some years that are more earthquake active than others? Or is it really pretty standard across the years?
DR. ABBOTT: Yeah, one of the most stunning ways of seeing or answering that question, which I always love to do in class…
DR. ABBOTT: …is there’s a guy named Alan Jones back at SUNY State University in New York and what he has done is done a computer program where every earthquake in the world is displayed in real time. You can go back to the year 1960 and start it running from then, you can also set it for magnitudes, everything above 5 or 6 or 7 or whatever. The main point being, as all these lights flash on this global globe, I always like to ask the students to look there, and say, do you see any patterns now? Watch the world. Do you see patterns? Is it heavy at times? Quiet at times? And the answer is, no, you don’t see a pattern. Now if you focus on a small region, you know, let’s say Southern California, for example, then statistically, you know, you might have a little bit more of – at one time than another.
DR. ABBOTT: But globally? No, you don’t see a difference. Remember, all these earthquakes are powered by the energy, the heat flowing out from the interior of the Earth. It’s flowing out from the interior to the earth all away around the Earth so, in other words, the energy supply, you could say, is more or less constant and then it’s just a matter of where do the rocks yield and rupture at any given moment.
CAVANAUGH: In fact, you can go on the internet and you can see all the earthquakes in California for a certain period of time and there are always some. There is always some in the desert somewhere, a little one over here, a little over there, so it’s always active in that way.
DR. ABBOTT: We live on a very active planet. A lot of energy flows and adds a lot of excitement and we get more and more of these disasters. Human population is growing so, so rapidly. You know, there was 3 billion people in the year 1960 and now we’re going to be 7 billion next year, more than doubling within the lifetimes of most of us here. So that means more people in areas where they’re put at risk and, again, that’s why we need to be able to build better so that that risk is reduced.
CAVANAUGH: Well, you’ve relieved our minds, not really a chance of an 8.8 here.
DR. ABBOTT: Impossible.
CAVANAUGH: All right, good to hear. I want to thank my guests so much. Dr. Pat Abbott, Professor Emeritus of Geology at San Diego State University, and Yvette Urrea Moe is Public Information Officer for the San Diego County Office of Emergency Services. Thanks for coming in and speaking with us.
DR. ABBOTT: My pleasure.
MOE: Thank you.
CAVANAUGH: And please post your comments at KPBS.org/thesedays. Coming up, we’ll meet the finalists in Orchestra Nova’s Next Star Contest. You’re listening to These Days on KPBS.
To view PDF documents, Download Acrobat Reader.
Please stay on topic and be as concise as possible. Leaving a comment means you agree to our Community Discussion Rules. We like civilized discourse. We don't like spam, lying, profanity, harassment or personal attacks.