Discussed USGS modeling technologies that show what a major earthquake on the Hayward fault would look like, and BART’s award winning Earthquake Safety Program.
TRANSCRIPT
Speaker 1:Okay.
Speaker 2:Okay. Okay. [inaudible]
Speaker 1:you're listening to method to the madness. 30 minutes show about the innovative spirit of the bay area. I'm your host [00:00:30] aliene Huizar and innovation is usually born from trying to solve some kind of problem. And one of the biggest problems we have facing us in the bay area is earthquakes. We've got the San Andreas fault, we've got the Hayward fault going right underneath the East Bay hills, directly at her memorial stadium here on the beautiful UC Berkeley campus. And I started to wonder what kind of innovative techniques and technologies do we have in the bay area to deal with this imminent problem [00:01:00] of a huge catastrophic earthquake. So I have two interviews for you today. One is with Brad, a guard a geophysicist from the U S G s that's created some really interesting, incredible 3d models that you can see on our website@wwwdotmethodtothemadness.org that simulate a large event on the Hayward fault. And then we speak with John McPartland from the Bart Board of directors who tells [00:01:30] us about Bart's plans to keep the bay area running. And in particular keep the Transbay tube operational in the event of an earthquake.
Speaker 2:Stay with us.
Speaker 3:[inaudible].
Speaker 4:[00:02:00] Okay. So let's start off by just saying, uh, your name and your Kinda rank name, number type thing. Brad a garden. Uh, I'm a research geophysicist at the u s gs in Menlo Park. Okay. And do you wanna just give me a little bit about your background? Uh, so my background is in earthquake [00:02:30] modeling. I'm concentrating on the dynamics of rupture, how faults actually slipped and earthquakes as well as the ground motions that are produced by the seismic waves radiated from the rupture. Okay. So, um, would you mind giving us a little bit of history on kind of the, that you're part of the modeling kind of where it's come from in the past and where we are right now. So, uh, people have been modeling earthquakes [00:03:00] in a variety of methods for several decades. Um, and with the advent of, uh, modern computers in sort of the eighties and nineties, um, the ability to be able to capture more sophisticated effects in earthquake, uh, ground motions is increased significantly.
Speaker 4:Um, and within the past couple of decades with super computers. Now we can do things in 3d that we could only do in 2d, uh, before. And so now we can do [00:03:30] a large, uh, uh, simulations of earthquakes for the damaging earthquakes, the ones who really care about, so magnitude seven and above, um, earthquakes. And we can capture their 3d effects. So we can, we actually create a model of the earth of volume and propagate the, uh, the rupture through the earth and then compute all the seismic waves radiated out through the three d structure. So, [00:04:00] um, as the geology varies from place to place and as a function of depth into the earth, we can capture those effects. Um, and it really takes advantage of several decades worth of work in terms of actually determining what those properties are based on mapping, uh, remote sensing, um, as well as seismic studies of probing the earth using both passive and active, uh, source experiments. So in some cases we can just sit there and monitor, you know, the waves from [00:04:30] small earthquakes that have been generated and in for what the geologic structure is. But then there's also been specific studies of creating a ref reflection and refraction lines like those used in the oil industry across various sections of the bay area. And all that information gets assembled into our three d model, which then we can use in these 3d computer simulations.
Speaker 5:Okay, great. Well, let's talk about the model that this is really what caught my attention. I was doing some research for this story and [00:05:00] these are really incredible models that you've built and right where Calyx I think is right there. So, uh, we, I'd like to understand this a little bit first for the listeners. So, um, how did you go about, um, just coming up with the idea for doing these models?
Speaker 4:Um, well, we really, I mean we've been doing sort of three d models for about 10 years or more. Um, and I've been doing models for about that long. It really started way back in graduate school for me and, uh, cal tech, is that right? Yes, I went to cal tech and, [00:05:30] um, that, that was in the mid nineties and that's when really the, the super computers became powerful enough that we could actually start to do these three d models with a realistic variations of the material properties. Um, and s uh, leading up to that, um, the centennial, the 1906 earthquake and we made a big push to, in the bay area to be able to improve our three d structure to be able to do simulations of events on the San Andreas fault. And so after we did [00:06:00] a 1906 like events on the San Andreas fault, the next logical step was to do them for the Hayward fault because it is sort of the other big major player, a fault in the San Francisco Bay area.
Speaker 4:Okay. So when you decide, let's do, um, you know, let's do a three d model of the Hayward fault, how do you begin something like that? So we began by spending a couple months of the modelers, um, myself as well as other people who we collaborated to do the modeling, [00:06:30] the three d modeling of the ground motions. Uh, we sat down with the geologists as well as the people who dig turned to the cross, the fault, the Paleo seismologists and sort of other geophysicists within the USDS and some of our external collaborators at Lawrence Livermore and Berkeley. And we developed sort of our, what our scenarios were as suite of scenarios there, where we would have main two large events, the main tune, like 6.8 to 7.1 [00:07:00] for the Hayward fault, incorporating, uh, the known history of earthquakes on the faults, um, how much slip we would expect in those events and the length of rupture.
Speaker 4:Um, and this is a, that's where we really looked at sort of past events is where as well as, you know, what is the latest information about how, say the Hayward fault may connect to the writer's creek fault under San Pablo Bay and would they go together? Um, and if they went together, you know, would it generally be, [00:07:30] uh, would the eruption need to start sort of underneath the bay or would it be able to make sort of a jump from one fault to the other? And we eliminated the possibility that, uh, in terms of considering the most likely scenario of it, having actually jumped across to actually starting, uh, under San Pablo Bay if it did rupture both of them. Um, but generally we believe that the two faults in most cases are going to operate independently. They may have events relatively close in time [00:08:00] because the stress is on, one will, uh, are when they're relieved in large event will actually increase the stresses on the other because they basically like end to end. Um, but in most cases we would expect them to actually rupture in separate earthquake.
Speaker 1:This is method to the madness. A 30 minute show about the innovative spirit of the bay area. I'm your host Eileen Huizar, and I'm speaking with Brad, a guard a geophysicist with the u s g s in Menlo Park who's telling me about a model. He's made a three d model [00:08:30] that simulates a 6.8 earthquake on the Hayward fault. Can you take me through this with a lotto? We're looking at as the right now, the 6.8 with a [inaudible],
Speaker 4:um, center in Berkeley. Uh, we're actually, well, they were actually looking at the ground shaking in Berkeley, but the rupture in this case starts down there. Fremont. Okay. And so we're watching the color showing the intensity of the shaking. And so this light is what we call the p wave. Um, and it's coming through and that's where you'd just be able to start [00:09:00] to feel a little bit of shaking. And then now we're about 17 seconds into the rupture and then we get the strong s wave. And that's where the intensity of shaking increases significantly. Um, and that's where you would sort of a, a person would have the sensation of rather than relatively balanced shaking, uh, in the case of a large event like this, this close to the rupture. Um, and when we look at our three d view, we see, um, some important f effects.
Speaker 4:If you look along the fault, the intensity of shaking [00:09:30] is higher. And then as you go away from the fault, the intensity of shaking is generally decreasing. But then there's areas like the Livermore area where we have a basin that extends the strong shaking away from the fault. And then along the Hayward fault, we actually, uh, have, uh, less rigid material on the east side of the fault. And so the intensity of shaking is slightly higher there than it is on the west side. Um, these 3d simulations, we don't have the very thin bay mud, which sits right [00:10:00] along the edge of the bay. And so, uh, when you include those effects, then these intensity, the shaking in these models would actually increase a little more. Um, so that would tend to slightly even out the shaking on the east and West sides of the fault.
Speaker 4:But in general, uh, with the softer sediments, um, and this is due to the fact that the areas east of the Hayward fault between the sort of the foothills all the way into the great valley is an area that's been highly be formed over tens of thousands to a hundred of thousands of years. And that's sort [00:10:30] of broken up the rock and made it a less rigid. Whereas underneath the San Francisco Bay, um, once you get rid of that very thin, shallow sediment that's quite soft, then you get into much more competent rock quicker than you do east of the heroin form. So does that mean, so on the Hayward fault where it's more broken down, it's less, uh, the impact would be less because it's more flexible or all the more flexible means that a, it acts a little bit more like Jello. And so it [00:11:00] tends to, uh, you can think of it as being a softer material that, uh, is allowed to move around by being sort of more flexible.
Speaker 4:It tends to move more when the same amplitude wave, uh, enters that medium. When it, when that amplitude wave enters a medium, if it goes into a softer medium, actually grows and amplitude, if it goes into a more rigid medium and actually decreases in amplitude. So, uh, that, uh, less rigid material means that it's going actually gonna amplify the shaking. [00:11:30] Um, and so, you know, if you are to be your sort of, your most desirable location is on bedrock, which is very hard. Uh, it means you're gonna sort of move maybe with sort of higher frequencies rather than sort of, uh, but you're going to move less than if you're on a, uh, a less rigid material. Gotcha. Okay. So a, the
Speaker 5:Hayward fall, it looks, it's going right along the foothills. It looks like it goes right into the Berkeley campus.
Speaker 4:So it goes right underneath [00:12:00] Berkeley stadium come up along, uh, the base of the foothills and then runs into San Pablo Bay at point Purnell. Um, and then running down, it runs down along the base of the hills from Hayward down into Fremont. Um, and then it sort of Peters out in some respects at the surface, but then at depth it continues and, uh, migrates over towards more, even with the Calaveras [00:12:30] fault, um, things at the southern end, um, uh, sort of just east of San Jose, it becomes quite complicated. The surface, there's a lot of secondary faults in between the Hayward fault in the car. The Calaveras fault.
Speaker 5:Yeah. I follow one of those earthquake bots on Twitter and there seems like there's always a little something going on down under San Jose, a little bit south of Santa. There's a lot of different things down there, right?
Speaker 4:Yeah. So there's a, there's sections of the Calaveras fault that have a lot of [00:13:00] small earthquakes and the Calaveras fault also is, has, uh, once you go farther south down, your Morgan Hill tends to have more, what we call creep in that the stress is being relieved almost continuously by just slow motion the fault. And so it's not as prone to larger earthquakes. And that's also true for sections of the Hayward fault near the surface where you tend to have a creep going on. So there's some sections, uh, in Fremont, um, [00:13:30] up through Hayward and then some sections near Berkeley where, uh, you have offset curves, offset walls, um, and, but these are primarily limited to just the very shallow, most, uh, about a mile to two miles of the, of the ground. And underneath it's locked. And we know from historical records that, uh, in 1868, there was a very large earthquake magnitude about 6.8 November on the hero Fox.
Speaker 4:So it's, even though [00:14:00] it has these unique features of slowly creeping up the surface, it's still capable of a large earthquake. And that was the last major earthquake on there, you Hayward fall, right? Yes. And, uh, 1860 was the last one. We know, sort of a definitive deep, um, and Mark Twain wrote about it and roughing it, and we did. So there's a, there's several like witness descriptions. Um, and before that, then it, uh, the previous event to that was somewhere around 150 years, but we don't have [00:14:30] historical accounts. Um, so we don't know the precise date. And so our uncertainty start to grow. Um, in terms of precisely when the last few events have happened. Um, but we do have a record of 12 events over the last, uh, 2000 years for the Hayward fault, um, in Fremont, um, and there approximately 150 years or something like that, about 150 years are ranging from anywhere from about 130 years to 107 years. And we're now [00:15:00] 141 years since right in the sweet spot, right? Somewhere near the middle of the time we expect a Hayward fault event.
Speaker 1:You are listening to k a l ex Berkeley. This is method to the madness at 30 minutes show about the innovative spirit of the bay area. I'm your host selling his arm. And we've been talking to Brad, a guard from the u s gs and Menlo Park, who's created some cutting-edge models on what the major earthquake that's about to happen on the Hayward fault will look like. Now we turned [00:15:30] our attention to preparation so we know this earthquake imminent. How are we doing on getting ready for it and searching around. I found that Bart actually has received an innovation award in 2010 from the Northern California chapter of the Earthquake Engineering Research Institute for its efforts and its earthquake safety program to protect the system in case of a catastrophic event on the Hayward fault. So I reached out to bart to learn more about the retrofit project that began in 2004.
Speaker 6:[00:16:00] Hi, my name is John McPartland. I am art director, but I'm also the vice president of the Bart Board of directors. And I'm also on the Seismic Safety Commission for the state of California. The original retrofit was designed simply to have portions of the system survive and other portions of the system to be able to be operational. [00:16:30] There is a magnitude in cost of about four times in order to be able to improve from survivability to operability. And the reason is you have to have much stronger base structures in the pillars and the list goes on and on and on. The biggest risk of the entire system was the Transbay tube. Uh, and that has since that that was the [00:17:00] first target for our retrofit. And it turns out that not only were we able to stabilize the, the weakest length, which was the, the juncture of on the Transbay tube as you transitioned into the peninsula itself.
Speaker 6:Um, but in addition to that, the bay was a lot more stable than we thought it was when we saved a great deal of money. Second issue along those lines is that because [00:17:30] of the recession, a lot of the contracts that have been coming in, um, are coming in, continue to come in at 20 to 25% below the estimate estimated bid. And the rationale behind that is that a lot of these construction companies aren't trying to make a real profit. They're just trying to make payroll. And so we've saved money there between the combination of those two things with the amount of money that we have saved, what we are doing now is we are [00:18:00] increasing the amount of operability sections so that for instance, the on Transbay or the Oakland y, which is the Oakland underground area, basically exits going in the direction of East Oakland, right at about, um, fifth hour, then east seventh.
Speaker 6:And from that point on, as soon as it goes, Ariel goes [00:18:30] above grade, it has a survivability quotient and the original design. Now we have enough money to be able to retrofit that for an operability all the way out to the coliseum station. It hasn't been done yet, but we have the money. It's on the books as plant, we're going to do it. That's very interesting. So a combination of factors has made the original bond money go further? Yes. Yup. Um, how do you determine [00:19:00] in terms of priority levels for survivability reasons, operational operability, um, there's a big system. How do you determine which ones is there? Is there a ranking that bar has in terms of what parts are more important than other parts? Yes, and the ranking basically is now, here's where we end up going beyond just servicing the local community. And what we're looking at now is, um, how [00:19:30] we can end up serving as a better component for partner with regional disaster planning.
Speaker 6:For instance, if we ended up comparing the now understand that the Oakland Coliseum, which is not designed as a refuge of any kind in the event of a, uh, major earthquake, but let's use a comparison of the coliseum and the Superdome. Now, the Superdome [00:20:00] was refuge of last resort. There was somewhere between 60 and a hundred thousand people in there that had no hope and no way out if we had correction when we have this catastrophic earthquake that is going to for a short period of time. But, uh, it depends on short, his relative term depends on whether you're in the middle of it or not. Well, there's going to be a two days or two weeks, there's going to be a complete collapse [00:20:30] of the infrastructure. Can't use the freeways, rebel in the streets on no water, no communications, no electricity and no way out unless you want to walk.
Speaker 6:Now realize that if you had those populations that were gravitating towards the Oakland College, Sam, now all of a sudden the calcium is empty because with we've got electricity and we've got rail, we're moving people a thousand at a time and we're taking them [00:21:00] to outlying areas either on the line that goes to Livermore or online. That ends up going to Richmond or to Concord or to San Francisco because there's five ways into the East Bay and that means there's five ways and there's five ways out we can end up taking refugees out. We can end up bringing a row a week and end up bringing resources in. If I could give you a visualization of what I personally experienced [00:21:30] during the Loma Prieta earthquake, I was the staging officer for a as battalion chief and the Oakland Fire Department as a staging officer for all the apparatus during the Cypress collapse and the initially we had, within four hours we had apparatus fire apparatus that was stacked up four blocks deep and a half a block wide down the side streets.
Speaker 6:It was total [00:22:00] gridlock and Cruz were standing there waiting to go to work and we put them to work and we tried to do all the rescue. But over the next two and a half days, the only way that we could end up changing crews was to have a pathway to bring a bus in and have crews simply exchange with one another and take our first cruise in and tired crews out. And we did that for three, four days. We did that until [00:22:30] the Saturday when Buck Helms was found and visualize that same kind of quagmire or gridlock or collapse of infrastructure and in a village and inability to get people out and resources in and take it from Fremont. And then certainly not for the entire things, but in patches from Fremont all the way to Richmond. How the hell are you going to end up doing that? How are you going to get the, the injured out and get the, the, uh, the resources in? If we've [00:23:00] got bart running, we can do that.
Speaker 1:This is KLX Berkeley. You're listening to method to the madness. A 30 minute show about the innovative spirit of the bay area. I'm Eileen Huizar and we're talking to Vice President John McPartland of the Bart Board of directors. Bart recently, one in innovation in exemplary practice in earthquake risk reduction reward from the northern California chapter of the Earthquake Engineering Research Institute. And I was asking vice-president McPartland about this award and the retrofit that's going on on Bard right now. And specifically I want him to [00:23:30] know about the Transbay tube. What would happen in the event of a huge earthquake and what would happen to the people underneath the bay.
Speaker 6:First of all, the, the two danger areas and the transplant to trust me to have is three and a half miles long. And you ended up having about 57, I think 58 sections. Don't quote me on that, that are 330 feet long. And each one of those sections then was put into place, uh, [00:24:00] welded and put into a trench that was dug in the bottom of the bait. And then they turned around and we ended up, uh, putting balanced on top of it. The big fear that we had was that the bottom of the bay was potentially unstable in the event of an earthquake and we would have to on build a better structure to hold it in place. [00:24:30] The Loma Prieta earthquake caused a lateral shift at the, on the peninsula side and the two flux points that, uh, were critical were at the Oakland vent structure and at the San Francisco event structure and at the San Francisco event structure, um, there had been a lateral shift that, uh, move the alignment or the tolerance to a very [00:25:00] short distance within, uh, inches.
Speaker 6:That's maximum tolerance for additional lateral shift. That was our first target. Um, not only did we end up fixing that first, I actually went down there and watched them do the, the last piece of work that put it into operation and basically retrofitted that particular section. Additionally, we have found that there has been no lateral shift at all on the Oakland side because [00:25:30] uh, basically we're pretty stable on the Oakland side. The Hayward fault is a long ways away, number one. And number two, it's a continuum of merit. The term that they ended up using in geology is a, uh, Merritt sand. So the consistency of the soil that actually goes to that portion where we ended up having the vent structure is continuous. And so we haven't had any movement there at all. Then the third section, like I said, was that [00:26:00] we didn't have to do any on retrofit at all during for the entire length of the tube because it's in a solid silt and a lot of balanced on top of, and that's not going anywhere.
Speaker 6:If I had to be anywhere in the bart system personally and I worked in the safety department and did a lot of training and the translate to, if I had to be on anywhere when a major earthquake hits, I would probably [00:26:30] prefer, I would prefer to be in the Transbay tube. And the reason is that if you're in the underground, then uh, your train can't derail, it'll slam one side and slam the other, but it's not hell yes, it candy real, but, uh, it's not going to end up, uh, doing nearly as much damage. And I have full confidence in the system, being a watertight and be providing enough power for us to be able to get out of there [00:27:00] salsa nights that we've got a lower gallery that we can end up walking through all, although it, it is a long walk.
Speaker 1:So there you have it. You can put those co underwater and the Transbay tube fears to rest courtesy of vice-president McPartland and [inaudible]. But we should all have a healthy dose of fear because this earthquake is going to happen. And I asked the question too, Brad Hagar, the geophysicists from the u s g s about what he tells [00:27:30] people to do in preparation for earthquake.
Speaker 4:Taking it out of the science world, you're an expert in this is what you've dedicated your life to studying. Um, so what advice do you give to normal people? And they ask you if you're at a party and someone's like, what should I do for an earthquake? What do you say? Um, well the key is to be prepared to have food and water on hand and have a plan of how you're going to contact family members. Then if you can't contact them, do you have a sort of an understanding [00:28:00] of how are you going to handle rel relatives, children that may be dependent upon you because it may be difficult, for example, particularly difficult to get across the bay a if there's a large event because of bridges may be out, maybe even if the bridges survive, then, uh, along the edges there may be some extensive liquefaction that causes difficulties in disruption of actually getting onto the bridge.
Speaker 4:Um, and our water supplies, [00:28:30] uh, especially for Hayward events, most of our water, um, comes across the Hayward and either in one form or another through pipelines. Um, as well as, uh, our power. A lot of our power comes across the Hayward fault. Um, much of those left lifelines have been retrofitted. Um, but then the distributions, the secondary distribution systems, a lot of those are still quite vulnerable, um, to disruption in earthquakes. So having enough water and food on hand. Um, uh, up to a [00:29:00] recently people were saying the 72 hours, and now it's, uh, ideally it's a week, um, because, and it's not so much that you wouldn't be able to get any water after 72 hours, but it's gonna be a lot more convenient if you have it on hand and don't have to, you know, perhaps hike a couple of miles or you go to, uh, a centralized distribution point where, uh, quantities may be very limited.
Speaker 1:This has been method to the madness on KALX Berkeley. I'm your host Ali in his r and I'd like to thank our guest today, [00:29:30] Brad Agar from the u s gs and John McParland from Bart, both of whom showed us that the innovative spirit of the bay area is alive and well in dealing with the problem of the imminent on the Hayward fault.
Speaker 3:You can learn more about this story@ourwebsiteatmethodtothemadness.org.
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