MR. KOJO NNAMDIFrom WAMU 88.5, at American University in Washington, welcome to "The Kojo Nnamdi Show," connecting your neighborhood with the world. At 1:51 p.m. yesterday, the Washington region was hit by a 5.8 magnitude earthquake, the biggest trembler to hit the East Coast in over 70 years. This hour, we'll be exploring what happened underground three miles beneath the epicenter in Mineral, Va.

MR. KOJO NNAMDIWe'll also be getting snapshots of how the earthquake affected our region. Today, many public school systems canceled classes. And the Washington Monument is closed indefinitely. I know where I was when the shaking started. I was right here in this studio talking with activists about living with HIV-AIDS. Our guest in New York heard the shaking in our studio, almost a minute before she started feeling the tremors in person. That's my snapshot.

MR. KOJO NNAMDIAt the National Zoo, down the street from here, the red-ruffed lemur started reacting 15 minutes before the tremors, while the great apes started climbing their enclosures just before the quake hit. What was your reaction? What will you remember? How would you grade our region's response? You can, of course, call us at 800-433-8850, or go to our website, kojoshow.org, and tell us there.

MR. KOJO NNAMDIJoining us in studio is William Leith, coordinator of the Advanced National Seismic System at the U.S. Geological Survey. Bill Leith, thank you so much for joining us.

MR. WILLIAM LEITHThanks for having me.

NNAMDII have seen this described as a shallow earthquake that took place about three miles below the Earth's surface. What does that mean?

LEITHWell, earthquakes can occur at, you know, from shallow depths -- shallow -- maybe just a mile or half a mile and then all the way down to three -- maybe 300 miles deep and -- but earthquakes of this, you know, in Virginia are typically shallow like this. They often -- when they occur, the energy couples into the air, and people hear them. And especially remarkable for this earthquake is how broadly it was felt.

LEITHWe have more than 120,000 reports from people in the eastern U.S. who have provided information on what they felt, what they experienced during this earthquake, going all the way from Florida up into Canada. And that's just characteristic of eastern U.S. earthquakes. They -- shaking is felt very, very broadly, even for a moderate-sized earthquake like this one.

NNAMDIJoining us by telephone is Jerome Rasgus, principal with Weidlinger Associates. He's the head structural engineer in the firm's Washington, D.C. office, and he spent most of the morning monitoring how buildings held up. Jerome Rasgus, thank you for joining us.

MR. JEROME RASGUSWell, thank you for inviting me. In fact, I just got back to the office, and several of my colleagues are still out on some other project sites. So it's been very entertaining today.

NNAMDIGive us a sense of what kind of damage you've been seeing.

RASGUSWell, it really depends upon the age of the building. You know, most of the monument buildings in downtown Washington, of course, were built before the seismic code provisions were implemented. And many of these historic buildings are of a significant weight or significant mass. They have the ability attracting higher forces than some of our more conventional buildings, simply because they weigh more.

RASGUSAnd so we have -- we're involved in two or three historic buildings that we visited the site. I can't be specific on the exact nature of the building or the name of the building.

NNAMDISure.

RASGUSBut all of them have experienced, especially up at the roof level, where these intricate detailed parapets and projections have exhibited minor and, in some instances, major cracking. But the building as a whole, putting that aside, have performed very well.

RASGUSAnd, of course, the newer buildings, you know, out of the, you know, from the '60s, you know, to present, at least the ones that we've taken a look today, they've all performed very well because it was mandated that they be designed to certain specified code provisions.

RASGUSAnd what is going to happen now will probably be -- this earthquake, 5.9, you know, the epicenter, that doesn't necessarily mean that Washington, D.C. experienced 5.9. It was probably something less. I have not seen the reports of -- in the Washington, D.C. area exactly what the magnitude was. But what is going to happen is that the -- once this information has become available, you know, the codes will be revised.

RASGUSAnd the codes will be revised such that either retrofit buildings or new buildings will have to be designed for higher earthquake forces.

NNAMDIBill Leith, right now, it looks as if we're calling this earthquake as having started at 1:51 and measuring 5.8. But going over our audio archive, we started feeling it strongly here at 1:52, and some of the earlier reports pegged it at 5.9. We just heard Jerome Rasgus saying he doesn't know exactly what it measures in the Washington area. How exact are these measurements? And what was the measurement here in the Washington area?

LEITHWell, we need to distinguish between the magnitude and the intensity.

NNAMDIYes.

LEITHThe magnitude, our final determination is 5.8, but that does have some uncertainty in it, probably about two-tenths. And so the fact that it bounced from 5.9 to 5.8 is really not at all surprising for the -- you know, to happen in the first tenths of minutes after an earthquake. The intensity is the measure of the ground shaking, and that's what varies, you know, as you go away from the epicenter.

LEITHThe highest intensities from this earthquake were in the range of seven to eight, that strong shaking that's capable of producing damages. So the damage reports that are coming out of the area of the epicenter are quite consistent with that. We've got schools closed in that county because roof tiles have fallen off.

LEITHAnd then in -- and then, further away, that intensity diminishes in the Washington area, about intensity three or four, which is a light shaking and minor damage, some content damage. People have had things topple over inside their homes, so things knocked off a shelf. I've heard reports of pictures falling off walls and that sort of thing. And then as you go up -- as I said, the earthquake was felt very broadly.

LEITHAs you go up to New York and then Massachusetts and then up into Canada, these intensities go down to about one. So that -- and then back to your question about the timing...

NNAMDIYeah.

LEITH...it takes a while for the wave as it radiates from the epicenter to reach distance. And that's a slow-moving wave -- and, in fact, the analogy, I think, people understand after the Japan earthquake is the one with tsunami. The water wave, the tsunami travels quite slowly. It travels at about the speed of a jetliner.

LEITHThe wave in the earth travels much more quickly, but still takes several minutes to get, you know, to move the hundreds of miles, you know, from the epicenter up to New York and Boston.

NNAMDIThat may help us to explain this. On the show yesterday, I was talking with three people about living a normal life while HIV-positive and how reaching out to help others had helped each of them better understand his or her own situation. Just before the quake, we had a caller who wanted to talk about a program with HIV-positive kids in South Africa.

NNAMDIOne of our guests, Carlton Rounds, was explaining his deal with a 9-year-old Mexican boy, how they think of each other as they take their meds for HIV every day. When we went back to listen to it again, we noticed, first, that you hear, well, a little bit of clicking before you really hear the quake. Here's what you heard if you were listening yesterday at just that moment.

NNAMDIAnd Deborah, you should...

MR. CARLTON ROUNDSYou know, and he said, okay. Now, the thing is, a 9-year-old boy in Mexico helps me with my compliance.

NNAMDIWait a second. Something is going on in the studio, and it is shaking here. That's why -- I guess we are experiencing some kind of earthquake or movement here. But, Deborah, you should know that South Africa is of particular importance to Carlton, because, Carlton, when you learned that you were positive in 2005...

NNAMDIWe had an interesting science experiment going on here. We were talking, as I said, about HIV-AIDS with guests in the studio. Joining us by phone from New York, the guest in New York heard the shaking in our studio but didn't feel it immediately until about a minute later. Explain what was going on there, Bill.

LEITHSo that's a reflection of the wave propagating up the East Coast from central Virginia. And so the shaking that you felt here was when that wave, as it travels across the surface, shakes the building here in your studio, and it's -- and because it's traveling across the surface at a speed of several miles per hour, it takes a while to get to New York. And then it takes a further while to get to Washington. And, yes, that is a fascinating science experiment.

LEITHAnd you're being able to say to them we're experiencing an earthquake, and then them, later, maybe a minute later, feeling that earthquake, you yourself provided a warning to New York that that shaking was coming. And we are trying now to take advantage of that. We're building an earthquake early warning system in California that does that. It uses sensors in the area where the earthquakes occur to broadcast a warning ahead of the ground shaking...

NNAMDIBill Leith or William Leith is coordinator of the Advanced National Seismic System at the U.S. Geological Survey. He joins us in studio. Joining us by telephone is Jerome Rasgus. Jerry Rasgus is a principal with Weidlinger Associates, the head structural engineer in its Washington, D.C. office. He's been spending most of the morning monitoring how buildings are held up. We're taking your calls at 800-433-8850.

NNAMDIIf you have questions, comments or specific stories of your own to share about yesterday's earthquake, 800-433-8850. You can send us a tweet, @kojoshow, email to kojo@wamu.org. Here is Neil in Silver Spring, Md. Neil, you're on the air. Go ahead, please.

NEILHi, Kojo. Yeah, it was pretty interesting yesterday. Actually, I live in Forest Glen, Silver Spring, and a bunch of stuff fell off the shelves and so on and so forth. My question to the experts is there's something called a piezoelectrical or electricity effect, P-I-E-Z-O, and then the word electric or electricity. It's a phenomenon where when you compress certain substances, like crystals or rocks, it emits electrical field.

NEILAnd I'm just trying to understand why these animals would have felt something. Obviously, they felt something -- me anyway, you know, five, 10, 15 minutes before we felt it.

NNAMDIWell, Neil, we'll be joined shortly after this by Heidi Hellmuth, who's an animal behaviorist with the Smithsonian National Zoological Park. But you bring up the science of this and energy being generated. I would like both Bill Leith and Jerry Rasgus to weigh on this.

LEITHThat's a very -- it's a very real effect, the piezoelectric effect. And it's been supposed for many years that what -- that might be a way of predicting earthquakes. But, in fact, there have been experiments done over decades to try to detect electrical or magnetic emissions prior to earthquakes, and they are proved to be unreliable. So it's not something that we actively monitor in a predictive way now.

LEITHAnd, in fact, the behavior from earthquake to earthquake just says that that's not really a viable technique.

NNAMDIAnd, Jerry Rasgus, how about the energy produced afterwards? It's my understanding there's a huge difference between a magnitude 4.0 and a magnitude 5.0 earthquake in terms of the energy produced. How does this energy affect buildings and roads?

RASGUSWell, the common measuring scale is the Richter scale. That's what's coded, you know, the 5.8, the 5.9. And, of course, as the number goes up, the intensity of the earthquake is considerably more. And just so your viewers would know, when you go from a Richter earthquake of 4 to a Richter earthquake of 5, there's not a difference of 20 percent, 5 divided by 4.

RASGUSIt's a factor of 10 because it's set up -- it was originally set up on a logarithmic scale. And so what that means is that there's 10 times the energy that's imparted or 10 times the intensity. And then as you go up, again, from 4 to 5, from 5 to 6, there's another 10 times. And that's why the damage gets to be so catastrophic as you get up higher in the numbers, that -- you know, as they commonly would do in California.

RASGUSNow, the one that we had -- I mean, we're in a -- I'm going to say that we're in a moderate earthquake zone, probably on the lower side of moderate. And what we experienced was on the higher side of moderate, not impossible, but highly unusual for this area, highly unusual.

NNAMDIGot to take a short break. When we come back, we will continue this conversation on reactions to the East Coast earthquake yesterday. We'll be joined by an animal behaviorist from the National Zoological Park. Still taking your calls at 800-433-8850. If the lines are busy, go to our website, kojoshow.org. Join the conversation there, or send us a tweet, @kojoshow. I'm Kojo Nnamdi.

NNAMDIWelcome back to our conversation about the East Coast earthquake yesterday. We're talking with Jerome Rasgus. He's a principal with Weidlinger Associates, head structural engineer in the Washington, D.C. office and had -- has been spending much of the day, so far, monitoring how buildings have been holding up. He joins us by telephone.

NNAMDIIn our studio is William Leith, coordinator of the Advanced National Seismic System at the U.S. Geological Survey. We were talking before the break about the delay between what occurred here and what occurred in New York with our guest in New York. And let's go to the phone because, apparently, Lisa in Washington, D.C. was listening when that occurred. Lisa, you're on the air. Go ahead, please.

LISAHi, Kojo. How are you?

NNAMDII'm well.

LISAI always get nervous when I call you, but I wanted to try really hard to -- I felt obligated to call 'cause not only was I listening to you, but I had recently, in the last 10 minutes, gotten out of the shower, dressed, was sitting on the corner of my bed. And so I'm sitting there -- and, like you said, we're kind of new to this. And if you've never experienced before -- I'm sitting there.

LISAAnd we've had painter contractors who've been scraping and painting this old apartment building for almost a week that I live on, about five blocks from the Capitol, on East Capitol Street. And I was freaking a little bit, but I thought, God, what are these guys doing? They're reminding me of, like, apes who are maybe, like, jumping on the roof of the building, trying to see how hard they could jump to make it shake or something.

NNAMDIYeah, a lot of people said they had that sensation.

LISAAnd so, anyways, I did freak out. When I looked up at the corners of my bedroom, and I -- I really literally did feel the ground move. I felt the bottom of this building swing back and forth, and all I could think of at the moment was what a mess my apartment is and how soon everything was going to come crashing down.

LISAAnd then people were going to see how messy my apartment was.

NNAMDIBut that didn't happen, does it -- did it?

LISABut then we were so grateful because, just as you're kind of sitting there like a helpless idiot, 45 seconds can feel like 45 minutes. But then the entire thing stopped. And when I heard your voice say, oh, something's happening in the station -- and I even heard the rumbling on your recording before I realized my corners of my room were moving.

LISABut your voice and your laugh -- but -- kind of kept my sanity at the moment because whatever had just happened to me happened to you, too. And then it was over, and we were both okay. So that's all I was going to say...

NNAMDIIt was a shared experience, indeed. Thank you very much for your call, Lisa.

LISAYou're welcome.

NNAMDIJoining us in studio now is Heidi Hellmuth, animal behaviorist with the curator of enrichment -- and curator of enrichment and training at the Smithsonian National Zoological Park. Heidi Hellmuth, thank you very much for joining us.

MS. HEIDI HELLMUTHGlad to be here.

NNAMDIOur caller mentioned sounding like apes on the roof. When a massive tsunami hit in East Asia in the Pacific in 2004, there were reports that Asian elephants ran to higher ground before the waves came. Animals are often much more attuned to tremors and seismic activity. What did you witness at the zoo?

HELLMUTHWe actually witnessed quite a few things, either through our visitors or through our keepers, observations of the animals. Some of the animals, like some of our great apes, in fact, your namesake, Kojo, one of our gorillas...

NNAMDIYeah, he's one of my favorites.

HELLMUTH...he is one of the animals along with some of our orangutans who actually dropped their food about 10 or 15 seconds before keepers felt the quake and ran up to the higher points in their enclosure. About the same time, our mom, Mandara, gorilla, grabbed her baby, who's two years old now, and took her up to high ground.

HELLMUTHAnd this was all before keepers noticed anything happening. In our birdhouse, we have a flock of 64 flamingos. And before the quake, they were seen huddling together and running to the water, which is something that they would do in the wild with any danger. They would band together for safety and then go to what they consider a safe place. So animals...

NNAMDIBut this was before, and the first animals, apparently, to detect the tremors, apparently where the red-ruffed lemurs. What did they do?

HELLMUTHThere was a report that 15 minutes before the quake, they started alarm calling. They are red-ruffed lemurs, however. They do alarm call for lots of different reasons. So we can't say 100 percent that it was because of the earthquake, but because so many other animals did show things, we don't know whether it's a sound they hear. We don't know whether it's the rumble in the earth.

HELLMUTHMost animals are more attuned to the environment around them than humans are 'cause that's their survival in the wild. But it was really an interesting day to see how the animals reacted before, during and after.

NNAMDI800-433-8850 is the number to call. Back to the science of this, Bill. On the West Coast, earthquakes come from a large tectonic fault line. But here on the East Coast, we are not on a fault line. So what exactly caused this quake?

LEITHThat's right. We're quite far from a plate boundary. The plate boundary, the closest one is down in the Caribbean, north of Puerto Rico and then out in the Middle Atlantic. And yet we know, from the small earthquakes that have occurred over the years and, actually, several large ones over the centuries in the east, that the earth in the Eastern U.S. is stressed and that it's pretty stressed close to failure.

LEITHThis earthquake, even though it's the largest in more than 100 years in Virginia, we know of other and larger earthquakes that have occurred in the Eastern U.S., in Charleston in 1886, off Cape Ann in Massachusetts in 1755 and other earthquakes sort of moderate sized elsewhere. So we know that the crust of the earth is stressed, and, in fact, for a seismologist, this is a maybe unexpected earthquake, but not out of the realm of possibilities.

LEITHThese are things that we expect to happen over long time periods.

NNAMDIJerry Rasgus, we got an email from Ellen in D.C., who says, "I live in a typical three-story D.C. row house built in the 1920s of brick, brick and, well, more brick. I was home during the quake, and the noise was terrible. But nothing seems to have fallen. My question: what should I look for to determine if there was any significant damage to my home? Should people like me hire an engineer or some other expert?"

RASGUSWell, if it would make her feel more comfortable, you know, to get an expert opinion rather than her own opinion, I would certainly agree with that. But if I were in her situation, what we've been advising people who've been calling on the telephone is to actually take a look in the inside of the house, take a look around the doors. Are doors sticking? Do you have cracking coming up from the top of the doors? You can do that visually from the inside.

RASGUSYou can do exactly the same thing on the outside. The row houses probably performed pretty well. My concern would be the row house, if they have a parapet, which is the extension of the brick wall above the roofline. Usually, that is the weak link in all of the -- in fact, all of the historic buildings that we took a look at today, every one of them had minor to major damage on the parapets.

RASGUSSo if there would be any concern at all, that would -- that's what I would look at. And, of course, it -- there's an understanding that the primary thing is verify that the utility...

NNAMDIUh oh, Jerry Rasgus, we seem to have lost you, even though the building is not shaking at all. We will try to get back with Jerry Rasgus very shortly, so he can finish that response. In the meantime, we go to Michael in Washington, D.C. Michael, you're on the air. Go ahead, please.

MICHAELHow you doing, Kojo?

NNAMDII'm doing well.

MICHAELI just want to -- hats off to you for being so cool under pressure and just saying, I think we've had an earthquake. That's not what I said when I was in my house, and I felt like there were a bunch of unruly burglars, sloppy burglars stomping on the roof. It's amazing what we went through. And my friends in the West Coast laughed at me when I called and talked about it. They said, oh, we have 5.9 once every other month.

MICHAELWell, they can keep them. We don't need them.

NNAMDIAny specific questions at all, Michael?

MICHAELPardon?

NNAMDIAny specific questions?

MICHAELNo real question. I just wanted to say I -- my fear now is that, after going through this and getting in traffic, we're not prepared for any major storm like this. It's kind of frightening (unintelligible) ...

NNAMDIGot you. Well, you should know that my initial instinct was to run, screaming from the building, but the microphone in front of me told me that I shouldn't be doing that. Michael, thank you very much for your call. It's my understanding that Jerome Rasgus is back with us. Jerry Rasgus, we were talking about some of the historic buildings that you were looking at this morning.

NNAMDIA lot of those buildings were built well before building codes included standards for earthquakes. Apparently, the big dividing line here is the 1960s, correct?

RASGUSYeah, the 1960s is when the codes really stepped up to the plate, and the municipalities accepted the requirements of the code. For many, many years, you know, D.C. and some of the other cities just flat-out excluded any of the seismic provisions in any of the, you know, applicable codes. And that's changed over the years, and that's changed for the better.

RASGUSBut still, most of the building -- most of the historic buildings that we have, you know, late 1800s, early 1900s, 1910, 1920, I mean, there were no seismic provisions that were mandated back then. So -- and depending upon the particular building and the function of the building and the importance level of the building, you know, there's a financial decision that has to be made, whether the buildings have to be retrofitted and upgraded for that.

RASGUSIt is a very expensive proposition to upgrade the entire building. Many times you're just better off upgrading some of the -- some of the more vulnerable pieces of the building would be pediments up at the top of the roof, like what happened with the cathedral or what happened with the Washington Monument. We're seeing that in some of the historic buildings, those architectural elements that are extended up above the roof.

NNAMDIHeidi Hellmuth, we got this email from Tina in Barnesville. "My son is a dog trainer. He was visiting two dogs yesterday in Chevy Chase. He was concerned about them before the quake hit. As one dog named Dizzy started running in circles, the other dog, Gaddo, (sp?) started foaming at the mouth. He called the owner and asked if this behavior was something she had seen before.

NNAMDI"She said no. And the house started shaking, and the windows started rattling all around him." Obviously, the animals in the zoo are different from the domesticated animals we have in our homes, cats and dogs. But from a behavioral standpoint, are there any similarities?

HELLMUTHOh, absolutely because what you're seeing in those domestic dogs are the remnants of the wild behaviors they had prior to domestication. So it's very common. In fact, dogs have long been known to be showing behavior in the preemptive stages of an earthquake or of tornadoes and hurricanes and things like that. So I would be surprised if people's pets didn't show some kind of odd behaviors before this because, again, they just are so in tuned.

HELLMUTHI think what they were showing -- those were probably just stress-related behaviors, and it sounds like they each had their own styles. I'm guessing Dizzy got his name possibly because of a habit of running in circles.

HELLMUTHBut what we saw with the wild animals -- and this is probably where the difference comes in, as most of the wild animals that showed certain behavior showed a normal defensive behavior that they would show for a predator or for any other kind of threats. So whether it's banding together, running inside, running outside, they would do whatever they would if they were in danger.

HELLMUTHIt just happened to be in this case they were potentially in danger from an earthquake. So their behaviors are maybe more survival-oriented than a domestic animal's.

NNAMDIDizzy may have gotten his name because he plays a trumpet at a rakish angle. But who knows? Bill Leith?

LEITHYeah, let me try and offer a potential explanation for this animal behavior. And as I described before, it takes a while for the waves to travel from the source of the earthquake out over a distance. And there actually are two kinds of waves. And there's the wave that travels down through the earth and comes back up again. And then there's the wave that travels along the surface of the earth.

LEITHAnd they travel at different speeds. And that means that, as you get further and further away, they arrive at a different time. And the wave that travels down through the earth and up is faster. And I think that the animal behavior that occurs in this sort of 10-, 15-second range before people feel the earthquake is actually that wave which comes through the earth -- it's called the P-wave. And it arrives earlier by several seconds or tenths of seconds.

LEITHAnd the animals, I speculate, are much better connected to the ground, that they may be able to feel that. And so if you see this sort of common behavior among multiple types of animals in these 10, 15 seconds before, they may be feeling the wave that travels faster. And then we, who are standing or less connected to the ground, are feeling the surface wave which arrives later.

LEITHIt's actually a bigger amplitude than the one that goes through the surface, and it's the one that causes the damage. So that's a potential -- it doesn't explain the lemurs that 15 minutes before. But those animals which exhibit these behaviors just in the seconds before humans experience, or before you see the building shaking, could be from this earlier arriving wave that they're more attuned to than we are.

NNAMDIHere's this email we got from Jeff in Annapolis. "Would you ask if there were any observable pre-quake activity during the time the animals started reacting?" Is there anything we could have observed, anything you'd observed at all?

HELLMUTHDo you mean about the earthquake itself or the animal...

NNAMDIYes, about the earthquake.

HELLMUTHWe didn't see anything. But, again, you know, it was the sound, I think, most people heard before they even felt some of the shaking. So we -- none of our keepers are staffed to -- the first thing that alerted them was the fact that the animals begin acting unusually. And then, pretty quickly after that -- again, with the exception of the lemurs, but I'm not completely convinced the lemurs 15 minutes before was because of the earthquake.

HELLMUTHIt might have been, but they also did it a few seconds before, like most of the other animals. And to go on what Bill was saying, I agree most animals, probably, it's that feeling. It's the tactile sense of feeling it. But there are some animals that do have ranges of hearing that can hear the sounds and hear the rumbles long before we do.

HELLMUTHAgain, elephants are great example. They're known to communicate and in for sound and spectrums that we can't even hear. So...

NNAMDIWhich is why they moved to higher ground in Asia.

HELLMUTHExactly. They've long been known -- and, again, it's interesting to see. We had some animals seek shelter and other animals leave shelter. So that probably have something to do within the wild what that animal considers safety, whether it's getting out in the open or whether it's getting under cover. So we saw different species acting in completely opposing ways, and it's probably whatever their particular survival strategy is.

NNAMDIYou are also the curator of Beaver Valley, the zoo's display of American beavers. How did those mammals react?

HELLMUTHWell, we actually had keepers in the exhibit with them at the moment of the earthquake, and they were feeding the beavers. And we also have hooded merganser ducks in the same exhibit. And the ducks actually began reacting first. But ducks are faster animals in their behavior than are beavers, and they jumped into the water. And then, right after that, the beaver's alerted.

HELLMUTHThey stood up straight, kind of looked around and then all sought the refuge of water as well.

NNAMDIOn to Gene in Aspen Hill, Md. Gene, you're on the air. Go ahead, please.

GENEHi, Kojo. Got a great show. Enjoyed it all every day, practically. I listened diligently from the time the shake occurred to all day yesterday to the radio, and I only heard the bridges mentioned once. Like 6:30, they mentioned the Ninth Street Bridge had been closed for inspection and not one word on the rest of the bridges. What's going on there?

NNAMDIJerry Rasgus, what should we know about bridges?

RASGUSWell, I'm sure that the Department of Transportation, you know, has taken the time to take a look at, you know, how much the bridges have moved, if any. I mean, that is a significant part of the infrastructure. You know, in the same fashion, last night, they walked all of the Metro tunnels to look for rail alignment.

RASGUSThey'll look for -- on the bridges, they look for alignment of the bearings. You know, have the bearings moved, you know, at the support points? It -- they -- there were thousands of people out yesterday looking at all of these things. And we'll wind up getting all of the reports. It's just going to take a few days.

NNAMDIWe're going to take a short break. When we come back, we'll talk with a Metro spokesperson and also someone who can talk about the Washington National Cathedral and what happened there. If you've called, stay on the line. We'll try to get to your call. If the lines are busy, go to our website, kojoshow.org. Join the conversation there. Or send us a tweet, @kojoshow. I'm Kojo Nnamdi.

NNAMDIWe're talking about yesterday's earthquake on the East Coast and reactions to it with Jerome Rasgus. He's a principal with Weidlinger Associates, the head structural engineer in the Washington, D.C., office. He's been spending much of the day monitoring how buildings held up.

NNAMDIJoining us in studio is Heidi Hellmuth, animal behaviorist and curator of enrichment and training at the Smithsonian National Zoological Park, and William Leith, coordinator of the Advanced National Seismic System at the U.S. Geological Survey. Joining us now by telephone is Richard Weinberg, director of communications with the Washington National Cathedral. Richard, thank you for joining us.

MR. RICHARD WEINBERGIt's my pleasure.

NNAMDITwo of Washington's most iconic tall buildings sustained damage from the quake. The Washington Monument is closed indefinitely after cracks were detected in its facade. Tell us about how the quake affected the National Cathedral.

WEINBERGWell, thankfully, first of all, yesterday no one was injured. And we remain closed today. I literally just came back to my office from a look up in the central tower. I was standing on the roof just not five minutes ago.

WEINBERGI was with our head stonemason and the team of engineers who are consulting with us on assessing the full scope of the damages. It's just incredible. I mean, it's a very -- it's been a very surreal 24 hours. We were all on staff here late last night into the wee hours, working and assessing and getting our communications straight. The support has been just tremendous. It's been pouring in from across the country and certainly here at home.

WEINBERGThe most significant damage was suffered to the central tower. If you can picture a cathedral tower, there are four spires on the corners. And three of the spires are pretty much gone. They broke and fell off in the midst of the earthquake. One is still there, but it's completely twisted on its axis. So our team is assessing the damage, the safety of the building.

WEINBERGLast night, we determined that the structural integrity of the building is sound, meaning, you know, the building is not going to fall apart. But, right now, it's just the matter of the safety so that any further elements, decorative elements that might fall, you know, we have the perimeter around.

WEINBERGWe're working very hard to determine an answer about how soon we might reopen, and with particular attention to the fact that we're scheduled to host the Martin Luther King dedication service on Saturday morning.

NNAMDIJerry Rasgus, buildings like the National Cathedral and the Washington Monument have a lot of heavy materials, especially marble. Does that affect how they weather these tremors?

RASGUSWell, what they -- the issue is, because they weigh so much, they attract more force. And the little minarets on the National Cathedral, I mean, those are these architectural embellishments or projections that extend up, you know, extend up above. And they're very susceptible to damages, as is any of the architectural decorations on any of the historic buildings at the roof around town.

RASGUSIt's just the nature of them. It's how they behave. They're not anchored in their base, you know? I mean, they're just put there with mortar and bricks. And if the movement is enough, you can displace the mortar and displace the bricks. And that's exactly what happened.

NNAMDIRichard Weinberg, are you looking to be ready for Saturday?

WEINBERGWe're hoping. I -- we have not made an official decision. Literally, as we speak, my colleagues are in a meeting that, as soon as we finish up here, I'll join, to look at what decision will be about Saturday in particular. And, of course, we have a huge weekend of events planned to commemorate the 10th anniversary of 9/11 that are just two weeks upon us.

WEINBERGSo we are really looking at solutions to probably put up some kind of netting or reinforcement, kind of like it would be a construction site to protect any elements that might fall. But, you know, safety is the first priority. And, of course, our next focus is to garner support. The cathedral relies on the support of individuals across the country.

WEINBERGDespite the National Cathedral in our name, we're not funded by the government, contrary to common beliefs sometimes. So we'll be looking for the support of so many to help fund the necessary needs to rebuild and fix the damage that occurred yesterday.

NNAMDIRichard Weinberg is director of communications with the Washington National Cathedral. Thank you so much for joining us.

WEINBERGThanks for having me, Kojo.

NNAMDIJerry, we've been getting a number of questions asking for advice about what people should do to determine whether they need to inspect their homes and structures. You're not a home contractor, but you're well-positioned, at least, to tell us what kinds of questions those individuals should be asking.

RASGUSWell, the primary concern is really the incoming utilities into the building: the gas, the water and the electric. And those can be, you know, visually inspected, especially on the gas side. If you smell gas, get out of the house. I mean, don't try to turn it off yourself. You know, call the professionals to do that. But beyond the utilities, then it's really just visual observation. When you know what the house looked like before, you take a second look now.

RASGUSYou look for cracks. You look for settlements, both in the interior of the house and the exterior of the house. That's what I did last night when I got home, with a flashlight. I mean, on the inside, it was lighted. But, by the time I got home, it was dark, and I didn't see anything. But I did take the time and look and check gas connections, check the electrical connection, check the incoming water connections.

NNAMDIOkay. Marjorie in Charlottesville, Va., you're on the air. Go ahead, please.

MARJORIEHi. Thanks. Well, I want to compliment your screener because he answered my first question, which was, yes, aftershocks have P-waves. So thank you to your screener. Good work. My other question is -- and I don't expect a definitive answer for this 'cause I don't think there's evidence, and I know it's controversial.

MARJORIEBut I'd be interested to hear what your scientist has to say about the possibility off fracking being implicated in an increase in earthquakes in this area.

LEITHYeah, I'll take that. I'll take that. Well, first, I don't know of any fracking activities in the area where the earthquake occurred. Fracking is this process where large volumes of fluids are injected in order to fracture a rock formation that has gas in it, you know, natural gas methane, in order to enhance the recovery of that. And fracking itself, actually, does not put very much energy into the ground.

LEITHAnd so we would not expect an earthquake of this size to have been triggered by that. Plus, we don't know of any fracking activities in that area.

NNAMDIBut there have been reports of some small tremors in communities where fracking is taking place.

LEITHThat's true. And it is mostly, actually, from the disposal that's associated with the fracking activity. When the -- after the fracturing occurs, a lot of water -- in fact, the gas is coming out in a lot of water, and that water has to be disposed off. And they typically inject that water back into the ground. And it's that injection activity where you're putting a lot of fluid back into the rock at depth that can trigger earthquakes.

LEITHAnd we've seen quite a bit of that in certain areas of waste disposal from fracking activities.

NNAMDIWe'll hear more about what's going on with Metro in one second. But first, Lilibeth (sp?) in Washington, D.C. Lilibeth, your turn.

LILIBETHYes. Thank you. I'd like to ask a question to Heidi, please, with...

NNAMDIPlease do.

LILIBETH...the animals. I think -- I'd like for all of us to look at the bigger picture of Mother Nature sending us a message. The animals were alert to what was taking place. How about the animals -- mammals in the oceans and what we're doing out in the oceans with sound waves, et cetera? There's a bigger picture. Let's connect the dots here. And I'd like to see more of a discussion in that realm because this is so unusual.

NNAMDII am certainly not enough of a scientist to connect to the bigger picture, but the question was for you, Heidi.

HELLMUTHI don't see them as connected because the -- one of the problems I'm aware of in the oceans with the sound waves, the manmade sound waves, it's related, but it is distinctly different. And there is a lot of science going on right now to look at things like sonar and things that are going on with some of, like, naval operations and things and the effect on animals, especially animals that use sound for hunting and navigating: your whales and your dolphins and some of your other species.

HELLMUTHSo there's a lot of science about that. And what is the impact? And how can we reduce the negative impact? Is it the location that these tests or these training exercises take place in? Is it the depth of them? Is it the frequencies that they use to try to minimize the impact? But that's very different when you talk about a manmade activity than when you're talking about something that's natural like an earthquake.

HELLMUTHSo it is a concern for some of those animals. And I think there's a lot of good folks out there trying to see what we can do to minimize it. And there are some great organizations kind of championing that cause. And it sounds like you support what they're doing to try to, I guess, keep everybody honest and make sure they're seeing the big picture of what they do. But I see them as also pretty unrelated activities.

NNAMDILilibeth, thank you so much for your call. Joining us now by telephone is Dan Stessel. He's a spokesperson for Metro. Dan Stessel, thank you for joining us.

MR. DAN STESSELIt's my pleasure, Kojo.

NNAMDIWhere did you look for signs of trouble yesterday? Do you have to go over every square inch of track?

STESSELYeah, we spent, from the time of the earthquake until just before the system opened this morning, conducting a very, very comprehensive infrastructure inspection that included 106 miles of track, which all needed to be walked, as well as visual inspections of every bridge, every aerial structure, every parking garage and every station on our system. That was a massive undertaking.

STESSELAnd we brought in, you know, personnel to -- that were, you know, having days off and were, you know, were at home, you know, just not scheduled to work at that time, to help us in those efforts during the overnight hours.

NNAMDIHow many structural engineers do you have to be able to look at that kind of stuff? And what did you find? Who does the looking?

STESSELWell, we do have engineers on staff for exactly this because we're in a subterranean environment and because we have bridges and aerial structures. So we do have those -- that level of expertise in-house and the equipment to monitor for those sorts of things. The system is also designed with some level of tolerance, right? I mean, you think about the vibration just from a train going by.

STESSELSo, you know, the system, the infrastructure itself, the tunnel walls, for example, the tracks are all, you know, designed with that in mind, that there are going to be vibrations in -- you know, in that environment. And that's part of the reason that we believe we didn't see any significant damage. All of the damage that was reported on Metro was minor in nature. We had, you know, a number of ceiling tiles at stations that came down.

STESSELWe had some broken glass reported, and a sinkhole that affected one track, but not the other track, out near Deanwood on the Orange Line. But aside from that, we weathered it pretty well.

NNAMDIHow about the elevators and the sometimes notorious escalators? How did they perform?

STESSELSometimes? Yeah, we sent out engineers to look at those as well. The only elevator that causes us any concern is there's one at Cheverly that may have -- that we just want to have an outside structural engineer come and take a look at before we put that one back in service. That's the only one with any sign of any kind of structural issue. So before we put that in service, we'll give that one a more thorough review.

STESSELBut the rest of them on the system are showing no signs of any structural impacts as the result of yesterday's earthquake.

NNAMDIYou spent this morning debriefing after a long day yesterday. Any lessons learned from this event?

STESSELThere are always lessons learned, and we're still debriefing. I mean, there are a series of meetings within Metro today, and we'll also be reaching out to our partners in the jurisdictions, at the command centers that we were interfacing with, to see, you know, where we can do better.

STESSELOne thing that we know went well yesterday was on the communications side, not just, you know, out of Metro headquarters, which -- this -- what was unique about this, for us, was this was the first emergent event that we live tweeted. We sent out more than 100 tweets yesterday, including two-way interaction with customers on our Twitter feed. And as a result of that, we actually picked up more than 1,000 new followers yesterday.

STESSELBut, also, we're hearing an awful lot of compliments on the way our frontline employees -- the bus operators, train operators, station managers and others -- who, you know, were in good humor and good spirits and kept customers calm as a result of the way that they were keeping them informed. And so we're definitely going to recognize our frontline employees for their efforts yesterday as well.

NNAMDIDan Stessel, thank you so much for joining us.

STESSELMy pleasure.

NNAMDIDan Stessel is a spokesperson for Metro. Here is Chester in White Plains, Md. Chester, you're on the air. Go ahead, please.

CHESTERHi, Kojo. I just want to contribute a little bit to the discussion. You were earlier talking about the Charleston, S.C. earthquake. The greatest earthquakes that we've had in this country were such that they would -- occurred with the epicenter in New Madrid, Mo., near St. Louis. And they rang church bells in Boston. So they travel great distances through the bedrock in -- on the East Coast or the eastern half of the U.S.

CHESTERWhat I want -- what I really want to contribute was, the research seems to indicate -- some time ago, there was a splitting movement going on within North America, more or less where the Mississippi River is. And the continent was actually moving -- you know, a part of it was moving east, and part of it was moving west because of, you know, tectonic forces within the earth.

CHESTERAnd that -- then, at some point, the motion splitting North America ceased, and...

NNAMDIAny evidence of that, Bill Leith? We only have about 30 seconds.

LEITHYeah, what you're talking about is something that occurred some millions of years ago. And the structure on which those Central U.S. earthquakes occurred about 200 -- in fact, this is the 200th anniversary of those earthquakes this year and early next year. It is the boundary of that part where the continent rifted apart many millions of years ago.

NNAMDIAnd I'm afraid that's all the time we have. Bill Leith -- or William Leith is coordinator of the Advanced National Seismic System at the U.S. Geological Survey. Jerome Rasgus is a principal with Weidlinger Associates, head structural engineer in its Washington, D.C., office. And Heidi Hellmuth is an animal behaviorist and curator of enrichment and training at the Smithsonian National Zoological Park.

NNAMDIThank you all for joining us. And thank you all for listening. I'm Kojo Nnamdi.

WEINBERGThank you very much. Bye.