Engineering Geology And Geotechnics – Lecture 15

now which i’ll be posting on blackboard as well on its the handouts called abandoning Richter I told you I was gonna hand it out today and that’s about why we don’t use the Richter scale anymore so that when you go for an interview somewhere you don’t embarrass yourself they say that I got a good pedigree going to Missouri S&T and they told me what’s actually going on but the reason is the stuff that I showed you last week it’s about site response magnifying the body waves and so they’re not they’re not reliable surface measurements aren’t reliable indication okay I hope I don’t run out I may run out here one two three I’m gonna run out looks like we got you guys all ready one two one two so I’m too short okay I’ll see if I have some more hang on anyway this is a nice concise write-up it’s only four pages not even four actually and that’s the best thing I’ve seen out there in terms of not chewing up more paper than it’s worth to explain to you what’s going on so that’ll be covered on the final the stuff that’s in this little handout I’m giving you I have the final scheduled for next Monday week from today the same timeslot four to six is that what you all have – okay all right it’s a multiple-choice open book final that’s not I’m not gonna try to make it hard for you and usually if you’ve done all the work and you’ve you know everybody scores pretty well on it the distance learners always score ten points higher on average than the class learners because my classes tend to be much more practice oriented because I spent 25 years in practice where I got here so I don’t tend to ask theory questions I’d tend to ask more about things that I covered in the lectures which are more concepts type things but it’s multiple choice and it shouldn’t it shouldn’t stump any of you if you’ve just done the basic work and you show up and and if you ask a question I will answer that question for everybody so I don’t know it doesn’t matter what yeah if you see if you think something is really you know not clear come up and ask me that’s what I want you to do when you go to work somewhere come up and ask the boss and say boss I just don’t quite get this and and I understand that you know I had five children you know my wife and I miss communicate every day of the week for 30 years so there’s always going to be communication things that are different because the way we communicate is predicated on our own unique pedigree of

experience with how we’re raised what culture were raised in that kind of thing so I understand that I’m gonna take the sweater off because I’m already too hot it’s a second all right now questions David did you have some you had some questions I want to cover okay the first problem the answer should be 118 West and it’s given his 18 degrees west all right all right so there’s a typo probably all right the only question I had I wasn’t I think I did the static too far wrong on the very last problem you had some parallel pipettes that were one meter by one meter face and a half different heights how did you I was trying to figure out how you determined why the last few toppled over and the ones right below it didn’t because you have a higher center yeah one has a centroid and then you have a force right that’s centroids but did you compare that to the searching course yeah yeah you have to look at the faces or some usually a customer fiction of 0.3 on the base rock it was they gave it as point to point – yeah it’s polished but like that was like that case I told you last week about that the water system they had the you know concrete top on it that weighed over a ton and it was completely thrown off so we went back and you know used a point three five point three point two five and in all of those we had to get more than a G lateral force to knock that thing off so when you get up on top of ridge lines that’s what you really you know you really get a topographic effect if it’s a steep enough ridge line you know that’s that’s a flat Ridge you’re not gonna get it but steep enough Ridge that thing’s that’s called the flagpole effect it’s really gonna whip around up there because it’s unconstrained and so that’s where the connection details and the structure are so important I mean that Loma Prieta earthquake these houses look like they had been blown up in an aerial attack there was just just splinters everywhere then all of a sudden there was an a-frame house perfectly right between all the all the destroyed ones right yeah same geology then you’re going Wow what’s different here well we went down to the county records after they opened up six weeks later got into the building files for those buildings in that building that was the a-frame had been built for a doctor the doctor had hired a mainstream architect the architect had hired a sub out some work to a mainstream structural engineer the mainstream structural engineer specified diaphragm framing system and a frames of diaphragms that’s all kind of sure wall you’re sure wall and diaphragm the same things the roof and connection details so it performed very very well the other ones were owner builders which we have lots of in the state where you know don’t tell me how to build anything don’t want your building code infringing on my freedom and they went out and built their own places which cost more money than the one that came through actually without any damage but it’s you know it’s when you go on those kinds of field trips and see those kinds of things that you realize the connection details are everything yeah speaking of that I watch the show on I think it was Discovery on Haiti and it was besides the fact that they didn’t have a steel reinforced concrete and said if they had had the right connections between the floors it would have come down the way did it would have at least been failsafe and they said it wouldn’t have cost more than about 15% more and you said more line number that’s percent more like two years yeah shouldn’t be more than half a percent typical on a new construction two percent when you’re trying to retrofit something so yeah when they’re higher numbers you know sometimes I they if they do concrete and like when we got the Kobe earthquake one of the things that I saw was they they came out with all of their steel and all the steel were the same lengths they were about four 12 foot long four meters and then they lapped all of them at exactly the same spots so they had a nice laps you know they were overlapping about 21 inches but you have that soft transition at exactly the same height throughout the structure so when the earthquake came along and of course with each cycle of loading and building

cracks some and that degrades the natural fundamental period of the structure well these buildings all broke right along the lines were all the laps where they didn’t stagger the laps you look in the Los Angeles Code way back in 67 they started putting in there you know you have to stagger the laps you can’t make all the laps at 12 feet then you’re gonna have a built in weaknesses own throughout the structure but those are the kind of things you know you learn when you go out to earthquakes and you see how things fail if you ever get a chance to go out on any kind of disaster go just go because you’re gonna learn things that are very hard to learn in the classroom you’re gonna see things that are hard to see that are there emotionally trying especially on Haiti but you remember there our codes aren’t meant to protect the structure they’re meant there life safety so that means you have to tear the building down and they have to put a new building up after the earthquake if you want the earthquake to be safer than that like we do for a lot of security installations military installations fire stations police stations hospitals then they have to be designed to a higher standard engineering wise and that’s called a functionality criteria that’s so you want it to function after your disaster and during the recovery phase of the disaster then you have to spend more money but you got to realize this really came up in a big way after Hurricane Katrina I was on the National Science foundation-funded team that was look at the flood control infrastructure and we were looking at the offshore infrastructure of the offshore platforms and way back in 1973 shale oil had looked at their offshore platforms in the wake of a platform leak in the Santa Barbara Channel in 1969 which had cost the oil industry dearly because there’s a lot of wealthy people that live in Santa Barbara there’s more fortune 500 CEOs that live there than any other city in America and when this oil started washing up on the beach those people just said no more oil drilling in our backyard it’s okay in your backyard and yours but not in our backyard no more oil drilling so the oil industry took that and said what can we do to make these things safer so we don’t have something like what happened in Santa Barbara this is you know almost 40 years ago and so they started looking at all the different things and they started looking at these new categories of hurricanes and they said what if we have a repeat of a category 5 well they’d only seen a category 5 in 1900 the Galveston earthquake sounds 73 years previous and when they started looking at cost-benefit ratio they found that once you get the factor safety you know typically designed for 1.5 and the Corps of Engineers had decided back in the 1930s to design levees 41.3 well that was because back in those days those levees were pretty much to protect agricultural areas not high-density urban areas so you use a lower factor safety because all you’re gonna lose is a year’s worth of cotton crops if that levee breaks but if you apply that 1.3 factor safety to a densely populated urban area you’re putting that area at considerable risk because 30% isn’t much when you look at all the unknowns so you look at shale oil what did they do they decided to design halt their offshore platforms for a factor safety of four because after they did an economic analysis they saw that the cost of replacing that’s and all the lost income from having it down for a year and a half justified it they saw that as you beefed up the connection details you spend a very little amount of money and you get a big increase in factor of safety and that’s why you need to have engineers making those decisions not accountants and attorneys and that’s what’s happened in our country in the last 50 years is the engineers are not making engineering decisions the decisions that have to do with finances are getting made by bean-counters lawyers and accountants who do not appreciate what factor is safety is they don’t they could even tell you a definition of factor safety but they’re making the decision and they’re looking at the engineer saying ah we don’t need it that safe well that’s how people talk who haven’t seen dead children if you haven’t seen a few dead kids that’s how you look at things cold hard cash real easy to do need to get out and look at some disasters and realize a little more duct tape a few

more screws those kids wouldn’t be dead is it worth the 20 extra cents damn right it’s worth it especially if you’re one of the kids so how safe is safe all right well I’ve done enough preaching for one day huh what’s the next question what are we gonna get a break what does this class gonna be done okay well let’s see we can go with today I have some of this kind of stuff today actually for you see all right estimating permanent ground deformations I’m not going to make you an expert in this category I just want to expose you to it what the state of the art is in this area it isn’t it’s come a long way how would we estimate permanent ground deformations now a lot of the panels I’m on our review panels things like for the World Bank Asian Development Bank Corps of Engineers Bureau of Reclamation Metropolitan Water District the questions we generally asked was we look at screening analyses to tell us if we have this earthquake which is the most probable earthquake in the next 30 years seventy-five years how much damage is it going to do and do we need to spend money now to go out and beef up the structure or can we wait till the earthquake occurs and then draw into our insurance pool so that’s the question here you’re asking most of the time and so we have to have simplified methods to look at these structures and look at the deformations how much strain am I gonna get and I remember strain has an engineering definition what is it remember strain is right change in volume over the original volume or the change in length over the original length so it’s got a very very stated definition so lateral spreads are a big big worry lateral spreads were initially recognized here in Missouri after the 1811 1812 earthquake sequence this is from myron Fuller’s 1912 USGS monograph and fuller wisely recognized that he saw these grubbin structures where you have a fault going like this fault going like that and the ground is dropped and then these would be parallel and to a channel and they would typically have an arcuate shape so he was the first guy to recognize lateral spreads and right here in the Midwest and what he theorized was going on there was some quicksand forming down there which is true liquefaction we’re losing shear strength for a period of time and the cohesionless soil silt sand gravel is behaving like a fluid without shear strength and while that occurs this whole mass floats over and laterally goes into some depression over here usually a stream channel or a bayman or something and so you can have very large tracts of land involved in these things and fuller I recognize that they are always at depths of 10 to 20 feet deep it was down some depth in the ground that these things were occurring well this is the picture that Walt Hanson drew after the 1964 Great Good Friday Anchorage Alaska earthquake and this is the picture you see in most the textbooks because you have this huge feature in Anchorage this one feature alone was about a cubic mile of material that’s a big slide and the escarpment going right through the downtown business district like this was a mile plus away from the nearest inlet so this was this was a really really big hunks of land that we’re moving around on discrete surfaces down here and actually in this case on silt horizons wasn’t even sand was silt and large tracts of land moving now you got remember this earthquake two to four minutes duration how many quibbling cycles of loading is hapless way out there you don’t usually start seeing these kinds of features to get past five equivalent cycles of loading and of course in Alaska we’re talking forty to sixty so it’s way up there and you start having earthquakes of that duration and you have saturated media with low cohesion you’re gonna get lateral spread so this is number one design problem right now in the Midwest we’re in a design of interstate highway bridge over the Mississippi

whether it’s down near hey died June he died and Dyersburg are up here in st Louis federal highway administration’s coming in saying how are you designing against lateral spreads and the do tease back here going what be a lateral spread you know Walmart talk what’s that we don’t know what those are we never even heard of that stuff before well I’d better start learning about him these are some very very large loads you have to design your caissons for or you got to do something in here likes and I like um stone columns to alleviate the liquefaction potential over a large zone so that’s a big design problem in geotechnical engineering you got lateral spreads as bad news and here’s the the one that everybody puts in all their textbooks this is a bootleggers Cove spread and Turnagain heights east side of Anchorage in the back side of Anchorage in 1964 and see what it was was a discontinuous series of silt lenses along the same stratigraphic horizons more or less so it wasn’t sand sand was up on top these were selfs within a clay unit okay and what happened here is when you have lenses it’s very important geologically because when I have lenses I’m not gonna get drainage when I shake it there’s only one thing that’s gonna happen the pore pressures are gonna elevate lenses are just like a big coke bottle with the top on it and you shake it all up again you uncork it excess pore pressure is all over the place okay so lenses are bad news and earthquakes lenses are very very very hard to identify if you bring a geotechnical engineer out here and they drill a hole here they do a cone penetrometer siding and they get silt here and they get silt there they get their ruler and they draw a straight connection between them like an interstate highway always always always always they don’t even know what the word Lenz means outside of going to get a pair of glasses LensCrafters so how do a hot Big Dave know you have lenses not easy not easy I have to be looking for them to see them and I’d have to do enough cone penetrometer soundings in the small enough area to try and identify them so not easy lenses are still one of the biggest geotechnical exploration problems we have in the business even when you’ve got smart people looking for so not not an easy one to solve here’s what happened to this and by the way this all got recently got rebuilt they put houses back on it because they need land and Anchorage what happened is you get a lateral spread you get horse grab and horse grab and horse grabbing and everything just moves on over and there’s a beautiful aerial view of all this outside my office if you want to see one taken by Chevron and given to their employees who live in this area during the 64 earthquake and hairy seed was one of my co advisers on my PhD thesis I worked for he worked on this and that was really his big huge contribution in his career that that’s 64 earthquake jump started him into geotechnical earthquake engineering in that particular study was where he achieved his first international thing is there potential for lateral spreads in the New Madrid Seismic zone oh yeah yeah they’re there all over the place they just aren’t recognized real well this is a site that the Missouri division of geological survey geological and land survey trenched they actually saw it’s north of Sikeston and the east side of a Crowley’s Ridge at a place called Holly Ridge and they got in there and it was an it was a quarry yeah when they got into the face of the quarry they started seeing all this very active faulting the nine meters of vertical offset in the Peoria Loess now the Peoria lost all blown in just in the last 11,000 years so that’s definitely very active faulting this is not even on the New Madrid zone this is along the Commerce geophysical lineaments seismicity on it active seismicity this is what I think’s going on at Holly Ridge I think we’re actually we’re not seeing down deep enough to see what’s going on down here in the stuff down beneath but when you when you have lateral spreading out here

somewhere you start getting blocks that go up and down and you get relative faulting between these blocks and you get these little sand dikes that shoot up and these sand dikes shooting up are just pervade crowley’s rich now you want to see sand dikes man Missouri and northeastern Arkansas just are filled with these sand dikes everywhere so this orange stuff is the stuff that’s liquefied and are partially softened enough that it’s lost shear strength for a few seconds and it’s moved around and then it’s solidified up after it’s bled off enough port pressure bleeds off enough excess pore pressure it solidifies like concrete doesn’t get quite as hard as concrete but it solidifies just strength then so this has to have shear strength in order to hold these blocks in there because if you have bearing pressure here and then you get the pure area loss being blown in over that at the end of the Glacial age the end of the Wisconsin glacial so what you end up with today is something that looks like that so that’s one way you could explain that observation at Holly Ridge so you can see here we’re doing good engineering geology is all about using the artistic side of your brain you got to use your artistic site you got to be able to sketch things like this and show them to your own people and to your client and say here’s one working hypothesis for this realizing it may may not be the only one there may be three or four we call that multiple working hi pathi sees that is a central core aspect of geomorphology study of landforms you have to have multiple working hypotheses because generally what happens is it’s a combination of factors that form the landforms we see it aside and what’s happened today in academia we get all these experts in these little tiny areas you know we get Loess experts we got sand dyke experts we got worm burrow experts and the experts to get them all in a room and what do they see everything is due to their particular expertise what you gotta do is crack their heads together like a football game and say don’t listen guys all this stuff could be going on here yeah we could have the worm burrows we could have you know we could have the sand dikes and we could have the Loess all this is probably interacting so multiple working hypothesis is a very central aspect you have you can’t get away from that when you’re trying to psych-out and characterize a site what things carve this site one of the first things you got to do is get off that site that your client site and look around the whole area to get an idea for the kinds of things that have shaped that site okay what are some of the field identification things we look for with lateral spreads well we look for saturated cohesionless soils capped by low permeability materials capped by things like clay and silt proximity to adjacent channels or some sort of natural depression prominent evacuation grab ins because as this thing pulls apart and moves away it’s gonna leave a gap of Robin that’s how Fuller found the things he saw this depression he noticed the depressions were linear and then if you walked out the depression it curved back toward the river in that direction and it curved back toward the river in the other direction and the light bulb went on in his head and he goes oh this is a slope feature but there’s no slope just flat boy you’re getting your cell mechanics class they go hey you can’t have any driving force here it’s just flat well that’s that’s the thing about lateral spreads they move on very that either totally flat to maybe up to three degrees that’s it you know now much slope on these things at all so here’s what they look like this is another picture this cartoon that I did this is down near Helena Arkansas this is the st. Francis River east side of Crowley’s Ridge and what we see is big lobate pancake shaped spreads that have pushed into the river channel and the key thing here is they leave this grabbin this depression that becomes a slump and it’s laterally restricted laterally restricted means it stops right here it doesn’t keep going it’s laterally restricted gets thinner thinner disappears thicker thicker wider deeper and then thinner thinner thinner disappears and then above this you see these arcuate scarps blocks rotational slumping we call this retroactive slumping and you see retroactively slumping once somebody shows you what it looks like it’s very very diagnostic of some kind of slope failure so you have a

horst and graben complex up here things going up and down up and down up and down because stuff is floated out this is the liquefied zone right here in orange see that liquefied zone we have a pancake shaped mass a material that’s moved out into some depression and we have the pull apart depression here so you have to have all three of these plus the channel down here you put those together and that there laterally restricted you probably have a lateral spread you have to have a deep channel to move into now here is the geologic setting of southern college Ridge and 50 60 years ago was hypothesized that there’s a fault a bounding fault coming up on the east side of the ridge and on the west side of the ridge nobody that I know of has a we found those faults and confirmed that they’re there but everybody believes that they are because Crowley’s Ridge is such a terrific topographic anomaly and it runs for 240 miles from Cape Girardeau Missouri down to Helena Arkansas long long distance and remember I told you before that they Mississippi River float over on this side of it most of the time and the ohio river flowed over on the east side of it most of the time so we get up here in the ridge this is dissected peoria Loess sitting on top of Pliocene sediments on top of tertiary units like the Wilcox formation the Claiborne group and the Jackson group well when I looked at the topographic map I was immediately drawn I just looked at all the topographic maps down in b12 one afternoon and my senior design students got a test I love lists looking at topographic maps some kids like listening to iPads other guys like watching pornography I love to look at topographic maps okay so turns me on and when I was doing this I started noticing these features divergent contours steppe topography head scarp evacuation grahdens and arcuate head scarves in this area these are smaller ones and right here so I said you know next time we go down there Bridget Doyle was my grad suit I said I really want to look this one over and this one real carefully because I think these are I think these are both lateral spreads along this old channel this river channel along here it’s a Langley’s River which flows them to the right down your short distance it flows into the st. Francis River which then the short distance down from that flows into the Mississippi River so we went down there and didn’t take long to figure out sure enough that’s a a big lateral spread feature and here’s that graben there’s the swamp that doesn’t drain where the ground waters or the waters right at the ground surface you can’t walk across it it’s just filled with water and it’s sitting right there where it’s supposed to be and then this thing in here is just a series of arcuate in echelon scarfs that have been backfilled with Peoria lusts and you have this very sharp arcuate head scarf up here cutting through the crest of the ridge so I was pretty pretty neat kind of exciting and when you look at it in cross-section this is what it looks like it’s the language River out here this is the lobate part right here there’s the Grabbe n– the gravan tells you how far it moved and moved about that far and then these are the retrogressive slump blocks that came down into that Grob and so this is a different style of land slippage than you have out here this is just a big lobate thing that’s cruising along on ball bearings on liquefied ball bearings and moving out into the channel and what this is this width here is basically the width of that river channel back in 1811 1812 was probably lighter than it is today but we had a very very well-developed arcuate scarp right up here that was about 60 70 feet high that’s pretty hard to get away from so there’s how much it moved that spread move to the right and there’s the lateral displacement behind it and then there’s the retrogressive slump blocks now I’ve showed you this little earlier this is the one that we think is the largest of these features identified yet in the world and this is actually down in southeastern Missouri the advanced lateral spread these are the the Benton

Hills this is the Commerce Gap the Mississippi River has recently blasted through this gap just in the last six to eight thousand years and it used to flow down here and went through this portion here and then before that I went all the way out here along the edge of the Ozark uplift and this had been this feature had been identified as a cut back from the Mississippi River cutting it and then coming around and that said that’d be easy that would be an easy conclusion to come to if you didn’t know about lateral spreads so there’s what it looks like and of course one of the big dead giveaways is we have the subsidiary scarf right here which is just as high 9 meters as this main scarf just an incredible large feature and so that was called the advanced crevasse play they thought the river broke through here at one time because all this drainage goes off in that direction it doesn’t drain back towards the river well if we look at that it’s 67 square kilometres one landslide feature that’s an enormous amount of real estate it has a very striking head scarp let’s look at that if we look at these drainages here these drainages are beheaded so those drainages used to be going this way and this thing drops 9 meters about 30 feet and started moving that way and this one dropped even more drop another 30 feet and kept moving that way and so you have a beheaded drainage which is a dead giveaway and then you have this arcuate scarp and then you have a channel that has been displaced to the east and has a very flat gradient boy you add all the things up and you just can’t come away but not thinking that’s a lateral spread feature so this one really bears having more research done on it why would should we be concerned about these things in the Midwest well guess where all the pipelines are that take all the natural gas and oil from the Gulf up to the Detroit and Chicago areas and Cleveland and on up they’re all going through this area and here’s the railroad line which has pipe lines going through it so the rail goes right through this thing over that mix carp ride over the next scarf that’s the main line going between Little Rock and st. Louis and so if you have pipelines coming across here pipelines are going to get pulled apart in this thing so there’s where the original channel probably was we look at the river to the river channel today is out here that’s how much it moved over kind of in that sort of a direction that’s where the channel was at one time it’s been displaced a good kilometer and a half and there’s the flat gradient anytime you have a gradient like this you either got one two things either there’s a dam right here or there’s some sort of blockage this is a landslide or it’s a dam there’s no way you get a fall wag profile looks like that unless you have some sort of hydraulic choke right here so that’s that’s what’s going on that’s why we run that kind of analysis all right how would I estimate the permanent deformations of features like this how much is it gonna move in a given earthquake and that’s what we get asked on these panels and that’s what you’ll get asked when you go out in the consulting world because your boss the first thing they want to know is do I have to go get some diamond stickpin downtown Chicago consultant to help us on this that’s gonna cost $300,000 so the boss wants to know do we need to do that well so you run what’s called a feasibility analysis or a sensitivity analysis to look at it and say well how bad is it the Corps of Engineers decided for their levee systems and their earthen embankments that if you get permanent deformation of less than a meter then you don’t need to do anything about it you don’t need to go get a consultant and do a whole bunch of retrofitting because less than a meter of permanent deformation soils pretty flexible it’ll probably survive that kind of a movement but if it’s more than a meter then you need to drop back and do something it’s a more rigorous analysis of it so if we look here’s our problem if I have a levy like the Corps of Engineers is looking at that’s a nice system because it’s all very mushy and if it’s all very mushy

and it’s homogeneous when I have a big earthquake motion lump I’m gonna spread that shear strain over a considerable distance and volume if I put this stiff foundation or the stiff material on a soft foundation layer down here I have a little layer of silt or clay down here that’s an inch thick that’s a bad situation because what’s going to happen if the if the modulus between the fill material and the foundation is very very different like an order of magnitude differ then this is going to behave as a rigid block and all that strain energy is going to be taken up as basal shear right along here so that little zone is going to feel a lot more attraction shear so that’s where engineering geology is everything in this kind of stuff it’s just everything most levees are homemade and they’re not engineered what does that mean that means they come out there were some big old equipment and they go you want to let it here we have a little lever here okay I’ll take whatever you got over there I’ll bow here and there we go letti now that’s about how much engineering went into him that little probably a little more so what they’re saying is they’re taking native material from right here and they’re moving it the shortest distance they can possibly move it so they’re borrowing it from right here and pawing it up right there now that’s good for this kind of a model because that means it’s difference between this stuff and this stuff should be what dn squared damn near nothing they should look pretty much identical the only difference is this is going to be disturbed it has some sort of compaction and you’re probably going to get this thing settling under the surcharge of that embankment that’s kind of stuff you should see so when you’re drilling a levee you’re going to look for things like that and you got to realize as you come off the levee and you go down here you’re gonna see less and less and less and less and down here you can see no impact of the surcharge now the big mistake they made but I criticized the court for I got a little you know I got a lot of heat for it but it was I had to make the criticism even if it been my brother or my parents that were running that that office down there they drilled the holes here and did all the analysis off these holes and said this material has something such a strength based on the tests we did you can’t do that why it’s called su over P factor P prime pre-consolidation pressure you have the most overburden sitting right on top of you right here that’s the strongest that Foundation’s ever going to be is right there but it gets weaker and weaker and weaker as you go out here and out here you got nothing overt except air so you have to take this number and reduce it by some measure that’s significant if you’re doing a slope stability analysis and they didn’t do that they took the numbers taken right off the centerline of the levee and used it for the whole cross section that would not have happened if they had had an external peer review board of people outside the Corps of Engineers reviewing it that’s why you have to have external peer review boards of people who don’t have ties to your organization they aren’t just retired from it last week they’re not tied to the organization who come in and look at it from an outside perspective and that’s been proven over and over and over and over and every single earthquake or disaster post reconnaissance report I’ve ever read has that in the conclusions every darn time and we still don’t do it cuz we save money ten cents sometimes 20 cents save money we don’t need external peer review we have this internal peer review alright that’s what I like for traffic tickets internal peer review yeah I was going too fast but I didn’t hit anybody I think kill anybody I shouldn’t get a ticket alright concept of shear strain if strain is divided over a considerable area you aren’t going to have much strain so that’s the lowest in simple shear strain like this that’s the lowest level of strain but if I have a big stiffness change between this material and this material or a big plasticity change this is more plastic this is more

brittle I’m gonna get concentration of shear along that boundary and this is the one you got to watch out for this is the leve one that’s why levees do pretty good an earthquake specially got enough clay and them got enough clay you’re good to go natural slopes has Stratego fee so tigre fee has differences in properties and stiffness and there’s gonna be your Bane remember we talked about in rock mechanics Dave’s view of rock mechanics very basic it’s all about differential strain one thing strains more than another you’re gonna have a problem so if we go out and we look after earthquakes along steep-sided ridges like this this is north of Northridge and the Santa Susana Mountains hundreds and hundreds of little seismically induced rock slides and when you go up and look at some of the larger slide features you see something like this I actually sketch this one in the Luzon earthquake in 1990 and what you see here is you see that they had liquefaction along discrete zones and they have sand dikes coming up but the whole mass only moved you know a couple meters now we’re gonna talk about why edit this is because of incoherence big landslides have big incoherence small little baby dance I don’t have any coherence because you’re small so when you excite them the whole thing just goes it’s like a body block on a sweep than a football game you coming around the corner you got acceleration F equals MA mass time acceleration some poor defensive ends stand-in there going boom you could have a hundred and sixty-five pound guy blow a 350 pound er right off the field because force equals mass times acceleration so that’s why when you’re playing football two steps on somebody makes all the difference in the world because it gives you some a some X acceleration one two BAM hit it if you just stand there like this if somebody you’re not gonna get anywhere near as much force so we’re also gonna learn about this kind of stuff I don’t know so what we do with all this stuff is we back calculate something called the yield acceleration case of Y now you run enough analyses of case of Y especially after an earthquake then you have some confidence in this number but as I’m going to show you this depends on the geology the topography and scale but that’s the way you get a comfortable feeling about K sub y is doing back analyses all right there we go there’s a big-ass block of the a B we call it and that big-ass block did what it went for a train ride it move now statically if I gave this to you on the final exam must be a great problem say back calculate defeating GLE for Uncle Dave these big heavy block what kind of slope was it sitting on PDF pretty damn flat not much of a slope but kind of friction do we got on that bottom of that block bath big-ass friction big friction so how did it get there donut not not doing all over well me at once just one person one person answered a time now earthquake yeah yeah something else going on here I mean we got something down here that lost strength and we have some conservation of momentum issue here because we’re pushing this thing and once it starts moving this is a big huge intact block and he’s gonna conserve his mass his mass isn’t disintegrating like a liquefaction failure and this is the kind you gotta watch out for this is a liquefied seam and you’re just rolling along the seam and the seam isn’t getting any pore pressure dissipation because it can’t get out can’t drain so this blocks traveling and this is the kind of stuff you see in big earthquakes and you just go frightened yeah it’s good to be frightening design things better all right so we go in to do a pseudo static analysis and we have some big old existing landslides and that’s usually the problem we go out to some place like coastal California 70 percent of the slopes in coastal California are covered with big old dormant landslides

and they built stuff on them all the time especially in the old days they didn’t recognize every slide so they look up the next day well yeah it’s an ancient landslide what does that mean that means I don’t have to analyze it it’s so old it could never possibly happen again and besides my legal liability is only for ten years do they stick the tongue out not usually that’s only when the lawsuit comes ten years so do we have a long term view no and it turns out they were wrong a lot of these started reactivating in the 1980s part of the reason was in Hawaii in California Oregon and Washington they developed them and they put in septic systems and leech fields and they brought the moisture levels back up to where they were in the ice ages they started reactivating them so we take them a lot more seriously today that we did 50 60 years ago now if I put have an input motion here peak ground acceleration 0.4 gee that’s 40% gravity and say okay how much is this thing going to move around that’s a sensitivity analysis so we’re going to do here is we’re gonna run through this thing and run a max you know run a big event on it and see what it does this is the case we’re looking at it’s called the Mission Peak landslide and this particular slide I worked on back in 98 99 s about a mile long drops 1,300 feet here’s the crown of it up here here’s the toe of it down here it’s about a mile long coming into this neighborhood of Silicon Valley executives now the had an area of about 85 acres seventeen million cubic yards how much movement is going to occur in an earthquake well we go back and look at it this orange area is the landslide that reactivated in 1998 the yellow area is the landslide complex that had been mapped by various individuals back as far as 1958 1958 they showed this area right here being in the landslide 1994 a little slightly larger area and the big orange area I mean the big the big yellow areas 1994 and then this is how much of it actually failed in 1998 so we look at that in cross-section it looks something like this we have a an active fault coming up right here all this strata is basically overturned we have the landslide in here we have a bunch of out-of-sync line frosting and we have a slide mass that looks something like this and the active part is the yellow part right in here that we’re seeing okay so it’s a series of coalescing earth flows some of which are up to 180 feet deep and individual lobes that are up to 900 feet long so when you have a big landslide it’s actually a series of landslides you have a lower part that moves first and then the middle part that moves second and then a upper part that moves third so it’s you have to divide it up into pieces to be realistic so there’s a real cross-section of the real fly here’s the maximum thickness of 180 feet so that’s about an 18-story building and so I have some the biggest pieces of this thing we’re right up in here here and right here and this one right here is the one that had the lowest factor of safety so I ended up concentrating on it and here’s what that one looks like and it’s actually there it is and it’s about 2,000 feet long and then I have the middle I have a section right here that’s about 1100 feet long and then I have a very small one right here that’s about 550 feet long now this is really important because these are some of the games consultants play and they play a lot of games trying to be friendly to their clients we call that being a client advocate when you’re advocating things for your client the reviewer calls it being a because you’re not telling everything the way it really is but client advocate sounds so much nicer than and you make a lot more money than the does but right here if you just look at this guy this is the one that’s going to have the most movement because it has the least in coherence in other words I can take earthquake motion and that are that strong motion is gonna be locked within this mass in the very short period of time where it takes a longer time to travel up through this entire mass so I can’t have that

point for G peak ground acceleration on this entire mass at exactly the same time unless I’m doing a pseudo static analysis so that’s what’s wrong with a pseudo static analysis it’s really only it’s only valid for small stuff for rigid blocks and small slides not for real-world stuff but we use it as a screening tool to tell us if we have to do more sophisticated analyses so it is valuable for that so I know that in the end this one’s gonna be the one that has the greatest deformation and we’re gonna see that like I know that from the get-go before I even run any numbers okay then what do I do I have to do some sort of realistic modeling of the water situation in other words this is 75 percent of the slide mass is saturated this is 50 percent of the slide mass of saturated this is 25 percent of the slide mass is saturated and when I do that I get different yield acceleration curves there’s my yield acceleration curve at a one-third saturated 50 percent of the mass saturated and 75 percent of the mass saturate now I’m not gonna test you on this stuff and you’re not gonna see this on your final I’m just giving you this so that I’m opening up a window and you can see what’s going on out in practice now here’s for the bigger slide mass and you can see I’m doing the same kinds of things and I’m getting very different curves why well because I’m doing a rigid block analysis for the medium-sized earth flow now and it’s it’s different scale and it’s got a different geometry and then here’s for the overall mass now when a client once do it when a consultant wants to paint a nice picture this is what they’ll come in with they’ll say well doctor otters we don’t think we have a landslide problem here you don’t you have a landslide Bronson biggest landslide in the Bay Area well but we did some analyses and we think you’ll find this interesting when we look at the you know of that whole slide you know we don’t get a very low factor of safety well no you don’t the bigger you make the slide the lower the factors safe is going to be because of incoherence so you got scale factors so we do this one and we look at it but you got to realize it’s this little one right here on the front where you’re gonna get the failure you got a house right here you’re hosed that’s what you’re gonna get decked so we’re looking at these things we’re backing out values and the values we’re backing out are the yield accelerations for these different sizes and different amounts of water that’s called a parametric analysis and that’s what computers are great for doing do I ever believe an answer I get out of the computer not on your life never ever the best we can do in the world of geotechnics isn’t like a hundred and fifty percent strains so I’m not gonna believe everything comes out of the computer but the computer is valuable for is to do a parametric analysis and to change these variables and see how much each variable tweaks the analysis that’s what’s important you want to know should I put in sub drainage how much sub drainage should I put in you can you can look at all those things and evaluate them that’s where it’s very valuable as relative assessments now what’s the appropriateness of pseudo static methods they use a rigid block assumptions and those should not be used to model earthquake induced movements of large large dormant landslide complexes okay they work great for this kind of stuff sliding blocks go with Newmark will you get a good answer yes we know that from back analysis of block slides small Lock slides and earthquakes all over the world like Northridge but those are small earthquakes and small landslides that ain’t the kind of stuff that does huge property damage and so it would even work for a small rotational failure like this when you get out into the real world and you have blocks and flows and things that are larger it doesn’t work as well there because things go are much more nonlinear okay so here we are flying around the Santa Susana Mountains just after an aftershock on Northridge and what do you see you see dust just flying up all over the place that’s because of this flagpole effect on these very very steep sided ridges these

ridges are steep they’re all around 40 45 degrees that’s very steep so you get something that’s steeper than 40 degrees you’re gonna have very significant topographic enhancement that’s what you would expect here we are flying along looking down on that a couple of weeks later up higher now we’re on a commercial flight coming from Oakland into Burbank we fly right across this Ridge I look down the ridge that’s a knife-edge ridge on the Santa Susana thrust and notice something I see a whole bunch of failures going to the right but I don’t see them going to the left that’s real typical of earthquakes what’s going on here is you’re in the hanging wall block the Santa Susana thrust is down underneath you here and what you’re seeing here is this thing getting punched by vertically propagating shear waves coming up at an angle like this and so this side of the ridge is really getting blasted but you don’t see it over on the other side of the ridge that’s pretty typical focus effect called focal effects that you see from topographic enhancement and the directionality of the incoming seismic wave train vertically propagating shear waves are the worst for liquefaction and for slope failures and you’re gonna get more of those when you have a reverse fault or a thrust fault and so strike-slip faults not such a bad deal right to the fault everything’s horizontal much much nicer less complicated easier to analyze when you have a reverse fault motion with high vertical component you get a lot of this kind of stuff now new mark by the way analysis works great on all these analyzes them randy Jibson that usgs analyzed all these slides in the Sam’s and mounds II he had an incredible fit between you know what they saw and what he what he theoretically backed out of all of it it was an incredible fit was way up on the 90 percent tiles okay so if you want to look at these masses and estimate how much they move one of the first things you got to do is estimate the fundamental period of the slide mass that’s good be a sanitary landfill as well you characterize this thing you say what’s the characteristic period of it characteristic period is going to be four times the depth divided by the average shear wave velocity that’s pretty easy to back out of it that’s what you need is the first calculation to do any kind of analysis then you’re gonna look at impedance effects now impedance is this shock energy that’s coming up through the bedrock which is nice and hard and as it goes into something soft it can’t transmit to the soft stuff as fast it is transmitting through the bedrock now here in the in the Midwest their impedance factor as I told you last week this sky-high it’s somewhere you know the shear wave velocity down here in the bedrocks between 1400 and 2800 meters per second that’s faster than bullets that’s just incredible because we don’t have a busted-up crust back here so you look at the average impedance ratio in the Peoria Loess and thus official materials we find back here post-glacial materials 165 to 180 5 meters per second so big change 20-25 fold I never saw anything approaching those kind of numbers working out in California nothing close not anywhere not in Yosemite Park you know anything of that close so you have this contrast think of it like this if I have sure wave energy coming up like this at 2000 meters per second and it gets up into something you only go 180 meters per second what’s gonna happen in ten seconds you’re going to have 25 times as much energy coming up into this thing more than it can transmit through it so you’re gonna store that energy and magnify it because of impedance contrast so that’s your big enemy that’s how you have to think about things you have to think about things as a dynamic system you got to think like back when you took for use civils you know go back to structural analysis fundamental course civil engineering structural analysis that’s how you have to look at it look at that doesn’t that look like structural analysis the impedance ratio is the density of the foundation times a shear wave velocity of the of the bedrock that’s two same things down here in the gray divided by density of the landslide times shear wave velocity of the landslide so now you have vertical incoherence and you

have lateral incoherence a lot of people again forget that this is very important if you don’t have strike-slip faulting which we don’t you know in the Midwest we have strike-slip faulting on the New Madrid and the Reelfoot rift is a reverse fault so that last big earthquake we had in February 1812 the one that blocked the Mississippi River for half a day and lifted things up 20 feet that was so devastating because it had a very high vertical component created Reelfoot Lake so here look vertical incoherence is the upward component of seismic energy it travels through the slide mass it’s going to alternately compress and dilate compress and dilate as that wave train moves up just like this it’s going back and forth but it’s coming up like that so that what that means is I’m gonna have one load right here and something different right there right there right there right there right there now we do pseudo static we just put the same load on all at one time we ignore the dynamics of the whole thing and that’s fine as a screening analysis it’s just not real accurate now here’s where you get in big trouble lateral incoherence back when I went to school in the Stone Age we look at all these huge landslides up in the San Gabriel Mountains and the San Jacinto and the San Bernardino Mountains and my geology professors were all saying well you know we live right on the San Andreas Fault and the San Jacinto fault we got all these big huge fault so all these giant landslides we see they’re probably all seismically induced by earthquakes and we all and we all grew up truth that we all believe that well then we had an earthquake 1971 San Fernando earthquake mag six nine six seven six nine then we had the San Northridge earthquake same round seven point one and we didn’t see all these landslides reactivate what you find out about landslides is the water table has to be high and the focal effect of the motion has to be coming from a certain direction to trigger them so you might have 10,000 landslides out there and in a big earthquake a hundred of them will get reactivated you don’t see all 10,000 all get reactivated all at the same time that’s a myth based on a lot of nothing so what you see here the larger landslides don’t typically move as one big huge unit because of lateral and coherence so now I got this seismic wave train these are horizontally propagating shootings this thing’s coming through like this and you can see you’re going to have a peak ground acceleration here but not there another one here they’re not another one here not there and so that wave train is traveling through the slide mass so when I got over to the luzon quake we had a huge earthquake and in the Philippines and I knew that northern luzon was just blanketed by huge landslides on altered ash beds and there in the tropics they get big moisture levels so I was expecting to see huge detachments never saw one big is earthquake what did I see lots and lots of little head scarp movements up here that were one and a half to three meters and the reason is the slides are so large they go out so many kilometers there’s no way you can have that large acceleration uniformly applied to this entire slide mass at the same time you have a bunch of body waves traveling through the thing like this that’s what’s really going on that’s the dynamic system and we can model those things with computers but it’s expensive all right so what do we do screening analysis we take the maximum horizontal acceleration we look at the window of duration for different magnitude events we back out our duration and then we look at the Nemean period of the acceleration time history and we look at durations of that and we’re going to use these factors to go to this chart which looks at the normalized maximum horizontal equivalent celebration at the base of the landslide and it’s normalized divide it out so we came in here we ended up in this zone this is data from earthquakes around the world and we’re going to look into here is at normalized fundamental period so we see here’s our band we’re going to be somewhere in there and if we take the mean or right about here and that’s where I brought my line down and you see

my ratio is just about one so the T one of my landslides versus the natural period they’re about equal that’s that’s pretty pretty interesting that’s just a coincidence that it worked out that way then I go to this procedure where I’m going to look at the yield acceleration divided by the maximum acceleration and I’m going to go through a series of simple range calculations because I have non-linearity I go to this chart which is a normalized based sliding displacement versus that ratio I was just showing you and in this particular case my zone is right in here and I come over to here come down and there’s my numbers go from here to there so there’s my range that’s the range I’m going to be in in this case for this is a for a 2d analysis it was 0.632 0.88 so the displacement I’m going to get is going to be between 1.5 meters and a 1.5 and 10 millimeters per second on the basel rupture surface so the expected range of permanent ground deformation I calculated for this one was three point six two thirty three point six millimeters which is well below a meter so that’s a third of a meter not not not even that’s three three centimeters not a big deal so when we got done with this whole thing here’s what I ended up finding out the sure enough the one out here on the front has the most likely movement somewhere between two and a half and nine and a half inches this one the scarp will move point two to one point three inches and up here point two to 1.5 inches and that’s exactly what you’d expect and that’s the kind of stuff that you see when you go out after an earthquake recon so you’ll see the smaller ones detach and move a lot more than the bigger deeper masses that are longer because of lateral incoherence so that’s what I wanted you to get out of this lecture so Newmark method gives an adequate evaluation for surficial rigid blocks but the berkeley simplified method predicts permanent ground deformations generally increase with a decreasing size of the landslide mass if the movements are greater than one or two meters then you may need to do a site-specific dynamic analysis like quad for pro something like that it’s going to be much more expensive all right we’ll take a little break right now and then go on with the next lecture are we on yet yes we’re not and so I

went to st. Louis and and leading up to

this I had months and months of phone conferences with different members of the Federal Reserve Bank system talking about the things that interested them and could I address these things and so that’s why you’re gonna see me talk about the kinds of things we’re going to talk about here and I think this is a good door just kind of crack open for you to realize that these are the kinds of dialogues we should be in as as an engineering community let’s start here peril breakdown of insured losses so insured law statistics what are they based on they’re based on what’s occurred in the United States over the last hundred years and that’s going to be statistically biased towards the events that occur with the greatest frequency so I’m not gonna see things that don’t happen very often within a hundred year period like 100-year floods two hundred year floods I’m not gonna see those because what I’m going to see the things that happen all the time now notice here where’s the what’s the biggest single area terms of property damage property damage is based on what people take bank loans out for because that’s where we lose a lot of money if your house gets blown away in a hurricane and it’s gone are you gonna keep making the house payments for the next twenty seven years you all laugh at me your banker is just gonna get stuck with that well the rest of the depositors at the bank are who’s gonna get stuck with it that’s to get stuck with it so yeah so so hurricanes are the single big dureena over the last hundred years 44% and this doesn’t count the biggest hurricane in our country’s history which is Galveston 1900 Galveston is not included in this and that’s also the biggest storm event we had in Missouri was the Galveston Hurricane in 1900 still the storm of record for Missouri as well as Oklahoma and Arkansas and a lot of the parts of the country okay the narrow fringe consists comprising 17% of the contiguous US land has more than half of the nation’s population so 17% of the country has more than half the population between the years 1980 in 2003 population of coastal counties increased by 33 million people or 28% this is a very significant number I want you to think about in 2003 23 of the 25 most densely populated counties were in coastal areas by 2008 over half of the American population live within 50 miles of the coast now we know this when we do faculty recruiting here we don’t get many people from either coast people on the coast want to live by the coast we get mostly people from the Midwest and people who want to get a green card real bad okay aren’t party animals alright so so what is that saying are we parking ourselves an area of greater risk yeah yeah people got off you know be 90% of the population 115 years ago were on family farms today less than 10% of the population is on farms I mean it’s not even 7% back you could even get those farm tractors now to drive themselves with GPS you don’t even have to be there for it I guess other than deceptive turn it on turn it off so for the people in the coast Wow now here’s you know tornadoes tornadoes and hail hail got my roof this last year while I was gone had to have a roof replace $23,000 that’s a very real one and that one tends to to stay pretty constant

this is earthquake now the big problem is we’re going to see with earthquakes is earthquakes come without any warning at all so we’re gonna have half the people we’re gonna have less than half a tank of gas in their car they’re not gonna have the options that somebody else has who has a full tank of gas in their car nice thing about hurricanes nice thing about floods is and tornadoes generally is you have some forewarning winter storms all the rest of these guys that the two exceptions are terrorism and earthquakes we don’t have any warning they just hit you and they’re boom so they have a big shock factor annum all right now we look at where earthquakes are earthquakes are along the suture zones most of the earthquakes are at boundaries of tectonic plates New Madrid big exception Yellowstone area another big exception so most of the world’s earthquakes are along these major tectonic zones this is just looking at earth quakes from 1960 to 2010 50 year period all right earthquake frequency versus magnitude the higher the magnitude the less the frequency but a magnitude 9 earthquake is equivalent to about a hundred and seventy two million tons of explosive Wow so the largest nuclear weapon ever tested was detonated in the Soviet Union 1961 that had a yield of about 50 million tons of explosives so equivalent of a magnitude 7.7 earthquake and fact that’s how we monitor all these things with the seismic network that’s not hard to do so we look at San Francisco 19600 wake right there New Madrid event bigger event notice Wow look at some of these Chile 1960 way up there Alaska 1964 or a magnitude bigger than the San Francisco earthquake pretty interesting how these things spread out so there’s the nuclear explosion there Novaya Slough typical variation earthquake activity since 1895 earthquakes are very very cyclical this is the bad thing this is what’s very hard when you’re when you’re talking to a client California I used to always have that the one I hated was coastal retreat I did a lot of dispute resolution work for the California Coastal Commission because they have a law that says you know you can’t have your structure closer than 75 times the average rate of close little retreat so if the average rate of coastal retreat is one foot per year the closest you could put any structure to the top of the bluff would be 75 feet away and of course people want to be right out there a little closer and I would get into all these battles with clients people very wealthy people usually and they’d say things like this I’ve lived here 27 years a lot longer than you’ve been here you’ve only been here 15 minutes and I’ve never seen anything I wrote off that Bluff not what do you say to that goodbye I’m going home see you in st Louis huh what do you say yeah yeah I see the thing is every year they’re sitting there there’s a greater likelihood that that cliff is actually going to have a movement sequence when you go back and look in the aerial photography on California coast what you find is it’s very episodic what does that mean that means every once in a while typically every 30 to 40 50 years there’ll be a sequence where you’ll get a lot of rain and you get a lot of storm activity and they coincide in a way that you get a sequence of cliff regression so all of a sudden 30 feet of cliff just goes overnight and it sits there for the next 90 years and does nothing but that cannot be appreciated in a human beings time frame of observation they can’t appreciate the risk because they haven’t seen the dead child yet out in the floodplain or in the in the building see so if you know when you go out and you look at disasters all the time you become very hardened like a cop you disable this is easy you know you just you need to do more but if you sat there and you’ve never seen the devastation with somebody losing everything then it’s hard to appreciate

now probably have is statistically look at this a whole bunch of activity very little activity how much are we going to worry about earthquakes right about here answer is not very much what’s going on here well it’s this horny looking thing huh that too much testosterone what is that thing that’s the Chilean earthquake in 1960 that’s a magnitude 9 big energy release so big basically you know it biases the whole chart if I didn’t have that thing there I could show these as much being much bigger features over here so that thing and we have another one of these with the Andaman Islands earthquake right here didn’t quite show up quite as big so right now we’re going back into a period of relatively high seismic activity that’s typical of the cyclical nature of natural systems and that’s bad for us as a Democratic culture because we like to plan for things and we like to budget a flat budget for stuff and that’s not how catastrophes work and then I’ll work with flat budgets you can go along for years and not spend much and all of a sudden you start having a lot more activity and you’re gonna go bankrupt that’s what’s happened to us with since 2005 whether the National Flood Insurance Program have was bankrupted by Katrina and Rita it still is so is the apparent increase in earthquake activity since 1994 relative to the period before is it just a coincidence well it’s just part of these natural cycles that we have and right now we’re in a higher earthquake cycle than we were in the 16 years prior to 1993 so let’s look at let’s look at our hurricanes hurricanes in the North Atlantic and we didn’t have any hurricanes come north of Cape Hatteras prior to 1935 that’s kind of interesting so there is a there is a pattern shift because we haven’t watched it for a whole you know for thousands of years or anything what you actually see here is you see there’s a cycle in these things a relative cycle and yeah we are an upswing right now and it could go down it could could stay up stay elevated so there we are prior to 1960 mean hurricane standard deviation and there it is since 1960 now what’s bad about this chart is where did all those people move to the coast down here you got more and more people moving into this zone at the same time you had higher and higher and higher risk and this is what’s bankrupted the banks because the bank’s actuaries just plugged through one mathematical equation and it’s the mathematical equation based on how many trains I seen go by going back as far as I can see so they’re plugging all this data in to their risk models and those are not good data for predicting where they are right now they’re way above what had ever been before way above the maximum where they’ve ever been before so in this case using that actuarial data to look at your risk for a homeowner’s mortgage it’s gonna get you the wrong answer remember we have this stuff when you took basic physics what do we call it skewness remember the term skewness and what was the other one there’s another term two’s cirrhosis or something that’s first how something’s changing rapidly well this look at that line that’s changing rapidly that should scare you you’re in the mortgage business because it’s going up like that all right now over the last 200 years Missouri has experienced the largest earthquakes in the lower 48 states but I would also say to you 200 years isn’t very long at all all we have to do is look at the Christchurch New Zealand earthquake we had back in mid-september that’s surprised everybody why that fault was thought to be an ancient dormant fault they hadn’t had an earthquake on that fault and 16,000 years the active fault on the South Island of New Zealand is over on the west side of the island Christchurch is over on the east side of the island I hop to the side of the island so they had this

magnitude 7.1 earthquake right underneath them and it’s kind of like put of prints for Haiti and they they didn’t expect that at all and that nobody was killed probably that was the timing then 6:15 in the morning but that people had been at work they would have had they would lost some people but that just shows you the problem we have with natural systems and that we haven’t watched them long enough to be a significant sampling so what does that mean what does Dave want you to learn about all this here’s what I want you to learn you ready to write down you’re always gonna get surprised by natural perils you’re always gonna have things happen that have not happened previously so what’s that do to your actuarial calculation it means it’s always gonna be wrong now this really worries actuaries and when I got into this with the Federal Reserve we got into a very spirited discussion believe me very spirited discussion because what scares the insurance industry is something they haven’t accounted for that’s big enough to do what bankrupt them that’s what that’s what they worry about that’s what they lay asleep at night worrying about did we miss something here that could bankrupt us okay and what you want to do in something like this you can say well we got this earthquake risk here we want to spread this to as many households as possible so that we don’t go bankrupt and give you an idea all state insurance after Hurricane Katrina and Rita they pulled out of Louisiana they said been there done that had enough we’re out of here you know we’ve had one after another after another after they just had Ivan in 2004 and next year to add Katrina they said we’ve had enough we’re out of here they pulled out its first time that one of the big 15 15 largest insurers in the country had just said we’re not going to serve that market anymore we think the risk is too high now here’s the National earthquake hazard risk we asked FEMA what’s the risk FEMA has fairly simplistic models these are based on assumed soil thickness of about a hundred feet over the bedrocks it’s not realreal detail these are by counties this coloration but here’s here’s this zone down here which isn’t doesn’t even really take into account the Wabash Valley seismic zone right up in here and so we have this earthquake risk in here that’s never been tagged previously what’s tagged me it’s based like me telling you you know you live in a hurricane zone but you never had a hurricane so how prepared are you gonna be you’re not you’re not gonna be prepared and nobody’s gonna you know there’s very few people are gonna be really prepared till this thing goes down and then everybody’s gonna say why aren’t we you know greater prepare for us why I didn’t FEMA take care of us well FEMA’s got four districts coming four regions coming together right there so that’s that’s really gonna be interesting as we’re going to see all right paucity of data paucity is a big English word it’s means don’t have much of it paucity don’t have much data what do we have we got one significant earthquake sequence 200 years ago when nobody was living west of the Mississippi River so we got these iso sizeable lines all the way across eastern United States hey we’re ringing church bells in Boston way out here what yeah what happens over here well you’re safe over here see there’s no lines over here no data it’s no data over there Native Americans did not keep their data they shredded all of it when they did these Sinese treaties that’s a joke dave tells you jokes okay so this is modified Mercalli index that’s what we had back before we had seismographs so did you feel it did it knock your chimney over that it knocked the building down did it knock you to the ground acceptor acceptor etc all right so where are the active Midwest seismic zones we know New Madrid active we didn’t even start instrumenting it till nineteen seventy three four seventy four why because somebody came in here and wanted to build a power plant in West Memphis across the river from Memphis and to do that you have to process an application about this high with the Nuclear Regulatory Commission that a Nuclear Regulatory Commission has the most conservative stringent seismic design criteria of any regulatory agency

in the world so they are tough and they look that they look at earth quakes for design purposes that are five hundred thousand your earthquakes correctly five hundred thousand year that’s very very conservative because the word nuclear you know just scares a lot of people and so they didn’t even start looking at this till they went to process that power plant thing and then they got into the you know the geologic records and they found this report by fuller of the USGS back in nineteen twelve and they go earthquakes so that’s how it started and that got the seed money to put the seismograph network down here to get a good feeling for what’s going on so we only got forty years of data coming up on 40 years of data not even at 40 yet and then in 1999 seismologists decided we have this Wabash Valley zone now these are all historic earthquake epicenters we’re showing here all these dots all over the place so we have this zone that’s recognized these are just not recognized they’re amorphous they’re outside the zone then we have the Wabash Valley zone we think that it spawns a magnitude 7 earthquake probably every thousand years or so but we don’t really know nearly as much about this one because we don’t have the kind of our net on this one all the instruments are down here and then we have this amorphous zone which I call the south central Illinois seismic zone I can’t say that inside the state of Illinois they’ll try to assassinate me you know they say you can’t call it that has not been decided that is not go away go away go away go away well their quakes are there so you call it what you want I call it the go away zone the go away earthquake zone that isn’t going away got some big quakes in there and so these are the sources owns that we know very little really about them the problem with south central Illinois by the way is it’s underneath a book you know 400 feet of glacial drift so you can’t go down there and look at the bedrock there and that’s why it still hasn’t gotten hasn’t gotten decided on now last good-sized earthquake was a hundred and fifteen years ago Halloween 1895 centered in Charleston Missouri it’s way down south east of Missouri not too far from Cairo Illinois and this I showed you the Cairo bridge last week this earthquake affected shaking intensity it affected an area 20 times the size of an equivalent sized earthquake would affect in California Wow Wow 20 times two times would be a big number 20 times unprecedented so that’s that’s a big problem here’s the problem I showed you this last week the problem is attenuation energy does not attenuate or lessen with increasing distance very much in the Midwest so what’s Dave’s conclusion don’t use charts generated with seismic data from California which is just about everything just about everything we have those things I was showing you before all those charts I had with all that data for estimating the landslide that’s all California data so you know not real applicable to being used back here you can’t use attenuation versus distance and magnitude versus distance data that’s out there in the data pool right now for the Midwest doesn’t work back here all right the other big problem is it’s shaking intensity varies from one area to another so where you live where your park has a huge impact on how intense the shaking is gonna be so I get the calls all the time whenever time I get quote in the paper I get about three dozen calls saying what the caller says you know dr. Rogers are you the earthquake expert world quit God of the world ask her question do you have a cashier’s check for $500 no I don’t say that I usually try to answer the question but what’s the question always in it no should I have earthquake insurance you know I can save 25 bucks if I didn’t have earthquake insurance you know so if you’re on bedrock you live in Rolla you probably don’t need earthquake insurance alright so I showed you this last week seismic site response whether you’re on the hills or you’re on the flood plains it makes a big difference in terms of how much the energy is going to be magnified I showed you this as well you’re on the rock you’re gonna feel a lot less shaking then you’re gonna feel being up on top of the alluvium if you’re up here on top of the bridge you’re gonna feel even more because you’re gonna have you’re gonna be that much higher above the ground so you’re gonna have the structure moving around in excitation relative to the foundation moving around and when you look at these things and you look at the spectrum on the rock

versus what you’re gonna feel on the ground it’s a huge difference and that’s the biggest impedance contrast of any place in the world and this is I think I showed you this last week too this is just looking at the difference in spectral acceleration with depth of the soil cover the alluvium and the deeper the alluvium gets the more this shifts over so that long period motion becomes more and more important and that’s very important to us in st. Louis because we’re at 200 kilometres plus from the source area so we’re gonna get long period motion from the New Madrid or the Wabash zone they’re about equal distant away so that means it’s the structures you know 0.8 seconds and above that are the most vulnerable the long period structures tall or long structures so we see I showed you this before last week to on the bedrock here you’re not going to get shaken too badly on the shallow cover which some of its st. Louis’s in this category by the way the shorter buildings are really going to get rattled big time the two to four storey stuff especially East st. Louis that kind of area really gonna get the hex shaken out of it but the longer period structures are the ones are gonna get shaken out in the deeper alluvium so when you look at this stuff Oh point two seconds specular acceleration that’s like for a two three storey building that’s the kind of stuff that we cover in the building code the building code basically covers up to three stories wood frame with nails and shear walls you do everything like the building code says you’re gonna get out of the building alive the building might take some you know additional damage the building might burn down on the fire that occurs after the quake because the the the fire mains are compromised by lateral spreading that’s what happened in st. Louis I mean in San Francisco in nineteen six and in 1989 in fact the sad thing about San Francisco earthquake I told the story to the Federal Reserve Board after they had the earthquake they and the city burned down they said how can we make this safer let’s have a panel of experts that’s always a thing to you so we’ll get some two professors from Berkeley we’ll get two professors from Stanford we’ll come in and we’ll say I’m professors make it so we don’t knock all these buildings down and kill 5500 people again so the professor’s turned in their report and they suggested that these structures be designed for an equivalent wind loading of 40 pounds per square foot now usually designed wind loading for about 15 and so when they started to design buildings they said oh this is gonna cost too much money we can’t get the the bond financed ears from New York and Boston and Philadelphia to give us this much money to build a building they’re saying cost too much money they can build a lot less than that in Memphis or st. Louis or Salt Lake City some other place so what they did is they rescinded the building code they passed in nineteen eight took out the seismic tenants well how do we couch for that well the reason the whole town burned down is because the fire mains were compromised so let’s make the fire mains so they won’t be compromised so they brought in engineers on this one and the engineers looked at and they said well the place where you lost the fire mains was at 7th and Howard three blocks south of Market in a made land area an old inlet on your bubbling a Cove so we’ll do is we’ll put a redundant system right down the middle of Market Street so they tore up Market Street and put in these two parallel fire main systems and they had emergency crossovers but they were locked off so now they had a separate system South of Market Street and North America because north of Market Street they got the hills that have the big fire storage tanks water tanks in them and if you break it at 17 Howard you don’t want to have these tanks all get drained out through that oh that’s what happened in nineteen six outs why the town burned down fire didn’t even start for five hours six seven hours after the earthquake so that’s what they did no seismic code but we have a redundant firefighting system that was in nineteen ten well along comes nineteen sixty four and who remembers 1910 they didn’t even have cars in 1910 hardly they didn’t have television they didn’t have radar they didn’t have any of the great things we have today and so they were getting ready to build the Bay Area Rapid Transit District and they had this tenderloin area down at the foot of

market it’s really sleazy a lot of sleazy bad stuff and they wanted to reinvigorate that and get it built up and so in fact they even put a BART station in down at the bottom because it was so bad down there and so they decided well we want to do something to stimulate redevelopment of this bad area and so that’s what they started doing and pretty quick they ran up against a unified uniform fire code UFC which says you know if you guys start building high-rises down here you need this much water and you don’t got the water for fighting the fires down there oh no oh we didn’t see this one coming what are we gonna do this is just killing us here we’re trying to make a better place to live in a better city and you get rid of the Tenderloin area and bring in some nice you know high-rises and a Hyatt Regency Hotel and all this thing no we got to do something let’s get our heads and put our heads together and see what we can do and the fire chief tell them well you know we got this redundant fire fighting system here you know and so some person says I know we can do we can open up these crossovers so we can double effectively double our firefighting capacity on either side they probably didn’t think of that back in the old days good I didn’t have television or anything you know didn’t watch doesn’t listen to radio even those days so they opened it all up and took out the redundancy so when the Loma Prieta earthquake hit in 1989 which an earthquake which wasn’t even 135th as big as the 1960 earthquake okay it was about wells about 125th as big where did the San Francisco water main system get compromised at 7th and Howard and it drained the entire city’s firefighting capacity welcome to the world kids where Dumbo’s blossom like bacteria every time you turn around there’s somebody who runs a city or a state or a county who doesn’t know jack bananas about the history of the place they live in and makes an ill-informed stupid moronic decision like that and San Francisco would have burned to the ground in 1989 in the marina district said no firefighting capacity and they had all these gas natural gas lines on liquefied made ground that had been built in 1915 for the Pan Pacific Exposition to celebrate the rebirth of San Francisco they put it on made ground the made ground all liquefied they lost the fire mains had no fire in the tanks because the tanks drain through 7th and Howard there’s only 6 nights a year in San Francisco where the winds not blowing in October 17 1989 was one of those six nights otherwise the fan town would have burned down again Wow so that’s the kind of stuff you go up against as an engineer and you better know your history because I came out with this stuff and boy I got called a lot of names I didn’t got called some bad names by some famous people until they found out I wasn’t making these stories up and one of them who was a National Academy member he said to me later we kind of apologized Jimmy he goes I’ve been around here 40 years and I never heard these stories yeah they don’t make it onto the evening news or on the halftime the NFL game or Vietnam they’re not even on the PGA Tour I mean you have to go the library and crack open some books to read about them all right so what our future earthquake hazard maps of the Midwest going to look like they’re basically going to look like this they’re going to track the channels that have the alluvial sediments that magnify the earthquake motion and these are your areas that have much greater risk here’s Crowley’s Ridge see that’s night that’s the place to be be up on top of Crowley’s Ridge you get a better view anyway and you’re not going to be nearly as much at risk for you do have seismically induced landslides up there get back off the top enough but that’s that’s what the future maps are gonna look like they’re gonna be along the major river channels does that mean you don’t get any shaking in here no you’ve got to get shaking in here it’s still gonna be serious in some of these upland areas for the 0.2 second spectral acceleration but not for the long stuff not those real big Peaks they’re they’re not gonna be a big issue for you all right well this is the most likely earthquake we expect the magnitude 6 to 6.8 what if that earthquake happened tomorrow what would get whacked in st Louis and a magnitude 6.5 earthquake well basically structures sitting on alluvium

deeper than about 50 feet structures are improvements on filled ground where the alluvium thickness is greater than 50 feet taller structures ie greater than seven storeys tall embankments placed on unconsolidated alluvial materials a lot of this over on the Illinois side of the river in the floodplain and tall structures situated on old soil filled basins and we have a lot of that actually out by the airport we’ve got many tall buildings out there so the airport’s got a big basin they’re about 150 feet deep so lake basin much lake sediments what are the critical infrastructure that we need to worry about well it’s the multiple span bridges as I told you last week in particular it’s the tail spans it’s the approaches and the one that’s got the government most worried is Poplar Street bridge built for interstate 55 1967-68 because all the fiber-optic network goes across that bridge also be showing that to you the Buried oil gas coal slurry water and sewer pipe lines crossing the flood plains are all at risk that’s a single biggest effect the high-voltage transmission lines crossing those flood plains also arrest the power plants that are situated along the major channels are gonna go down that’s a big factor for us because that’s most of our thermal plants are located along the major rivers and water treatment and sewage treatment plants along the channels all of them are along the channels and underground storage tanks now what is the non critical transportation infrastructure that could be affected well barge traffic that’s a big unknown PIMs what time of year what kind of year you’ve had when that occurs the fuel pumps are gonna be made inoperative by the loss of electricity this is the single biggest factor affecting recovery on Katrina you couldn’t get gasoline within 200 miles of New Orleans there’s no electricity no electricity don’t pump the gas you can’t pop the gas the drain network is gonna be compromised in the reclaimed floodplains places like the Bootheel of Missouri railroad corridors are going to be disrupted which affects getting heavy things in Interstate secondary highway Network airport runways and fuel handling facilities and the municipal off stream water storage tanks and the distribution system here’s a good example of that here’s the Louisiana offshore oil port loop system we bring in about twenty six percent of the nation’s domestic production comes in through this area like this and it comes up and distributes well that line is coming straight through the New Madrid Seismic zone right here so that’s gonna affect the cost cuz of supply and demand for everybody the cap line carries 1.1 million barrels a day of crude the plantation pipelines 26 million gallons a day liquid fuels and the colonial pipeline a hundred million gallons a day so these are these are major major infrastructure elements for the central u.s. fact of the biggest ones other refined oil products pipelines you got all kinds of pipelines running this corridor I call it the the Tulsa Chicago corridor and this is right in the New Madrid zone here we have seven pipelines I’m going to show you this on north side of st. Charles County right here going through and you’re gonna have a shock factor because having fuel unavailable is gonna cause a lot of turmoil and that’s going to be unprecedented and it’s likely going to necessitate rationing that’s never occurred before by the way we haven’t in rationing since 1978 crude oil and natural gas pipelines where do these things go we’ve got 17 lines that actually cross the New Madrid zone 17 major lines that cross the Upper Mississippi embayment and then we have the lines that come and bunch and go through st. Charles County now how did this happen well this is all geology geology controls everything got all these lines coming across and they want to come around this big metropolitan area how do you get around a metropolitan area without going bankrupt and and y’all the attorneys and everything what what you do is you group everything up here into this agricultural area that’s in the floodplain and you go around st. Peter’s and st. Charles and come out to the peninsula and you cross over right here just above the confluence between the Missouri and the Mississippi so we got seven pipelines bunched right here just

upstream of the water intake for city and county of st. Louis about the worst possible place to have the water intake so there’s what it looks like on a geologic map the section on the state engineering geologic map of st. Louis County and st. Louis metro area there’s the pipelines in red coming across they used to be on the internet they’re not now they come right down here and they cross right here right above there’s the confluence right there so they go through here now is this a problem right here no that’s buried right in here that’s the problem we’ve had all kinds of breaks where these pipelines cross the levee right here 17 breaks in this area since 1946 more than any other spot on the Mississippi River why because their trenches you how do you backfill underneath a round pipe in a rectangular trench you don’t you’re supposed to put it in slurry some sort so they’ve got all these breaks that occur along here routinely the problem is where these come back out of the floodplain over here and go on to the bedrock that’s where they’ll break that’s where they’ll be you’ll have the problem because you have a sudden change in strain so how about cyber physical infrastructure this is a big one why because we use cyber technology to exist each day and so we have to look at our reserves than our redundancies in these kinds of systems because they’re going to topple and go down like a domino just like the power system does if we don’t look at this kind of stuff with a very very increasing view towards having a robust system a robust system is one where you you’re able to break it in a few places but the whole thing doesn’t go down and so we call this ICT which just means information communications technology we have to have just-in-time management procedures so that we handle this thing and manage it right at the time these things occur because we depend upon these for all of our critical communications like seeing if our kids are alive at the local school or grandma’s still alive at her place or you know you’re gonna want to make those decisions before you get in the car and go running over there now who do you go see first kind of thing fiber optic cables probably one of the greatest I think the greatest inventions of the 20th century were fiber optic cables why do I say that they’re composed composed of strands of glass and plastic bundled together they transfer a laser light through those fibers through internal reflection and they can transmit in tremendous amounts of data as compared to electrical conductors such as copper wire now here’s what makes them so special the next one third-generation fiber-optic cables came out in 1973 the third-generation ones which we have now transmitted 10 trillion bytes per second down a single strand using the same cables that were buried 25 years ago there’s no other technology that’s out there that we’ve been able to retrofit like we have fiber a pass where everything’s going fiber-optic now what does that mean that means the reader we put on the end has gotten increasingly more sophisticated we’re using old fibers but new readers let’s the only place you can do that we should do that with your car or with your body this is the same amount of data in one second that’s stored on 1900 full-length audio CDs or a hundred and fifty million simultaneous phone conversations Wow that’s that’s hard to even get ahold of now here’s your major fiber-optic cable network in the Sam st. Louis metro area and this looks good until you get to the Mississippi River so we see a lot of switching offices these stars are switching offices so we have a lot of redundancy in the network out in West County but everything is grouping down and grouping down and going across the Poplar Street bridge including all of the national geospatial-intelligence agency stuff from down here by the bush plan and Arnold all goes up through that network across the Poplar Street bridge for the Poplar Street bridge is your critical cog and the whole thing amnesty approach spans on the east side of that bridge that I’m most concerned about right here it’s going down the main span is not gonna go down so I’m bedrock all

right how vulnerable is our electric power grid in the Midwest this is what I get the most questions about from people who are on the more scientific and engineering side of thing and they all ask me is this are our kilise heeled Achilles heel is that our weak point well here are some of the popular concerns that I hear and I’ve been on several call in programs for for some of the radio stations and one of the concerns number one is is there enough energy to meet the public demand yeah there’s sufficient energy in the National Grid if we look at Ameren UE Amer in a union electric system they’re based in these two states and Missouri and Illinois they supply the power for Rolla right down here and the big factor here is stalling disaster recovery your recovery time today is a single greatest impact on economic law and the number one factor is electricity do we all use electricity I mean how you gonna charge the cell phone well you can charge it with a car if you got a car charger but you can’t pump more gasoline into the car think about it if you had an earthquake in January or February that’s when the big ones occurred last time that’s a lot more serious than having it and the summertime just because of the heating issue all right where most of the power plants they’re a little hair along the major rivers back my power being I’m with them with Rural Electric out here my power comes from this guy right here this is the New Madrid plant sitting right over Earth quake central well the chances of it going down about a hundred percent it’s gonna go down so are there sufficient spare parts on hand to repair the downed power lines and transmission hardware this is our Achilles heel no when we start electrifying the United States 1920s st. Louis one of the first cities come up online we had one lower there was one in City in 1913 Keokuk Iowa but basically 1920s and we got rural electrification out here in all parts of phelps county about 1956 so 1922 1956 so that means a lot of the infrastructure is getting to be 80 years old its aging go out and look at a switching station here in Rolla we have an earthquake we have big heavy components and transformers transformer falls down or if we have a a ceramic insulator here that breaks where are we going to get a 25 year old transformer or a 40 50 year old insulator and the answer is we don’t have them they wait till they break and then they use what spare parts they have in the stockpile in the yard in st Louis and then after that they order them they have to order them to be fabricated somewhere in Iowa or Nebraska or outer Slovakia they don’t know where so that you know we’ve never had a major regional disaster where we’ve had to order parts from a large area now what about the power grid why aren’t our public utilities upgrading their transmission networks to make them more resilient and the answer is nobody wants high tension power lines in their backyard they want them somewhere else they don’t want in the backyard because of the cancer scares and so the transmission network is congested and that transmission congestion has been increasing every year we specially see this with a brownouts in the summertime and that’s what causes the power lines to overload and when they start overloading we get these cascading failures and what the utility guys are telling me is you know this is the part we’re having the biggest problem with because there’ll be one critical component in the system that was just about ready to fail but we didn’t know about and then it fails and that wasn’t in our model and then that causes an overload over here and that goes down and then we get these cascading failures so we’ve seen this with the wind storms and the ice storms over the past few years so what happens then as we get transmission gridlock and that’s only going to get worse and then that next decade because we’re putting more and more juice through the existing lines that we have and that’s because of the worry about electromagnetic effects having causing cancer and the transmission lines are unsightly is a transmission network vulnerable to

induced seismic hazards so yes any of the transmission towers that are on more than 15 metres of unconsolidated sediment especially in the Bootheel area are very very vulnerable so how fast can you get it restored that all gets down to manpower availability what we have done a good job on over the past sir decades is mobilizing more and more of the workforce to go into different states and help bring people back online and we saw that during during Katrina Africa Trina what are the negative certainties all these things the speed of recovery the ease of recovery duration and the public perception are all very important if a business has to shut down and move it’s very hard to woo them back they get you know they get operating in some other place it costs them money to move every time so we have situation reports today this is one in Katrina we have a lot more tools out there than we ever had before one of the problems we have in the Midwest is that we do have four FEMA regions all meeting right here at the New Madrid Seismic zone so we have four different regions having to coordinate with one another and we have to have good disaster plans and the way you get good disaster plans is you have to have exercises you have to exercise your plan so that everybody knows what’s expected of them when they disaster comes and so that’s what didn’t happen with Hurricane Katrina with the school bus drivers they had never exercised them to save money so when the hurricane came they just booby took care of the families and left and the buses got got wet so the biggest economic impact is how fast you can restore the power grid we haven’t done real good in that area on the wind storms and ice storms that we have they’ve been pretty local we also have the underground storage tank issue which we haven’t had a deal with yet that’s been a big issue in all the earthquakes that I’ve gone and visited because it’s the ready fuel and if you we also have a barge traffic which has never been impacted previously which we depend upon so the actual cost is somewhere between 50 and 70 billion dollars we had a repeat of the New Madrid events like a magnitude seven seven a maximum event it’s very very high and you’re gonna have a fickle factor that’s very hard to gauge and that’s the public confidence is a public confident that we’re making a good recovery and that we you know people are gonna get up and move their businesses so we’re not able to gauge a lot of these kind of things in the current models that we have right now and so they’re working on those things but that’s that’s going to take several decades to work out so I’m going to go ahead and end it there because I need to this is our aging infrastructure just turtle in it that there with UC tracking different kinds of elements looking at highways sewer systems water supply electricity telecommunications and and of course those things systems get older they get more more vulnerable okay I’m going to stop there and pass out the the course evaluations I need to get a volunteer and we’ll take these back to Patty tomorrow somebody want to volunteer do that okay and I’ll give you the envelope in all right you