Faulting California

Gerry is a geologist and professor of Integrative Biology and curator in the Museum of Paleontology he received his PhD at UCLA and then moved on to UC Davis for twenty-one years or so I think he was that and then finally found his way to Berkeley about 15 years ago or so looking at at Jerry's web page one of the things I noticed was a an anecdote about his becoming interested in paleontology and had to do with reading a Donald Duck cart coming for when he was about seven that he says and Huey Dewey and Louie I think I remember the Ducks nephews right we're running through a hall with a number of dinosaur skeletons that had been mounted fossils and there was a door with the word paleontologist on it and Jerry sort of thought to himself I don't know what paleontology is but that's what I want to do for the rest of my life because I can run around halls with dinosaur skeletons in fact he's taken it a bit further than that his work on biology and geology has allowed him to run not only through museums with skeletons but throughout the whole world with skeletons he and I have worked in many of the same places the Caribbean and we talk South Pacific Mireya Berkeley has a biological station Papua New Guinea Australia but he's actually done me one better I think he's a bit tougher so he's also worked in the colder waters of the Antarctic and as well as Siberia and the Russian Arctic where I would never go so with that today's talk is going to be faulting California Thank You Jerry thanks Roy especially about the Donald Duck business okay if you turn around just quickly and look straight back for blocks in that direction is it's the Hayward Fault so before I do anything with my own talk here today I want to talk to you first about what to do in an earthquake how many of you know what to do in an earthquake okay what have you done what have you done in this room already to protect yourself from the San Andreas Fault here's the earthquakes that just happen in the last day the last week and the last few hours and I drought downloaded this at 7:18 this morning so this is the latest word from the USGS and all of those seismic stations up there including Berkeley's which could fall down in the big earthquake that's coming on the Hayward Fault which could happen anytime after right now so the first thing you should do is look around this room think about what are we taught to do in an earthquake duck under something what are you going to duck under you're going down there well I'm going in this little hole under here okay and there's only room for me now look around the room false ceilings they'll be coming down on top of you look at that projector up there now not all you have to worry about this because remember these are these are northwest-southeast trending lateral slip faults so the motion is going to be like that so you guys right through there should worry about that thing coming down I'm not going to worry about it because I'm going to be under this thing up here but this is the problem I've talked to the seismic engineers around here about this building Roy knows about this and they say you should be prepared wherever you land to stay there for three days because that's how long it will take them to rescue you if the ambulances and fire engines can get here right afterwards and the other people realistically they say seven days now I'm going to be under here for seven days so I brought my earthquake bucket it's got water it's got seven little bottles of water that's not enough I've got three granola bars that's because I eat them I keep them under my desk in my office if I get hungry and so I eat them so I have to remember to replenish them and I have some candy that a Brazilian visitor gave me I have my first aid kit and some aspirin because it's going to get tiring under that thing and I've got a book in here oh well actually I didn't bring it because in my office the bookcases are attached by two little angle irons and a Molly bolt and they will I'll have plenty of books there's come down like that but I'll probably be bored and I need a flashlight to read by and I have a screwdriver and my rock pick which is about the extent of my mechanical abilities and I'm going to get out of my office if I can with this and my colleague Carol Hickman told me well you're well prepared with all this stuff but what goes in Scott to come out so this is my bucket and when the quake happens maybe in 20 minutes I'm going under here with my bucket so I hope you guys have this in mind think about what you're going to do in case there's an earthquake while this lecture series is going on it could save your lives let's take a look then at why California has this kind of activity and it's all due to plate tectonics and as you know probably and I'm not going to spend too much time on this stuff plate tectonics is essentially the spreading of the ocean floor and it's lateral movement and it sub ducks underneath the continents over here and when that subduction takes place this subduction is not smooth you'll see a little movie in a moment that shows it looks smooth but it's not it's jerky in fact subduction zones generate mega earthquakes not like the little ones we have on the San Andreas Fault which only get up to about 8.2 these generate things like nine point five earthquakes in Chile or the Sumatran one so these subduction zones are killers and then we have lateral slip transform plate boundaries here and although the San Andreas Fault is not in the ocean that in fact is what it is so here's California we have all of this in California all of the plate tectonic features we have divergent boundaries here in the Gulf of California and the Imperial Valley we've got transformed boundaries false the san andreas system because there's lots of faults just in the Bay Area the major ones are San Andreas Hayward Calaveras and a bunch of little ones and then we have convergent boundaries up here at the Cascadia Trench and that's a subduction zone killer zones all of these are problems for us so we could expect in California to be exposed to mega quakes on this subduction zone to normal earthquakes on the San Andreas system and because of the mega quakes that are generated up in all the way around the Pacific to tsunamis all of these are related let's look at this from a perspective though in terms of people getting killed in tsunamis in recorded history in California and nor in fact all of America there have been about 245 people killed in earthquakes three thousand four hundred and fifty-nine have been killed three thousand of those are estimated to have been killed in the 1906 earthquake but we don't know for sure we know that there were about 700 Europeans killed in many many Chinese they estimate two thousand three thousand but nobody's assess that in hurricanes are the big killer naturally almost twenty thousand people in the history of time how does this compare to other threats to our lives here's the data for terrorists including the war in Iraq about five thousand Americans killed so far guns since 9/11 have killed ninety eight thousand people twenty eight thousand a year cars have killed almost 160,000 this year alone forty three thousand people have died on our highways half of them not wearing seatbelts and secondhand smoke has killed a million four hundred thousand so by these standards Americans just killing Americans not including Terrace 1 million six hundred fifty five thousand earthquakes maybe three or four thousand so what we're talking about is not big numbers in terms of the hazards that we are experiencing so in addition to having your earthquake bucket with you when the earthquake happens turns out that these guns ninety eight thousand people killed they're mostly spouses and family members shooting each other so in an earthquake don't get near your spouse oh thanks in an earthquake don't drive and don't let anybody smoke around it those are the first three things to worry about then get out your earthquake bucket and start using it so I'd like to show you a movie here of the plate tectonic motions of California the North America really and this is a clip from the museum website which you can just see there let's look at this I'm going to just run it here first and it goes fast that's seven hundred and fifty million years of Earth history in a second let's take it slowly though here's North America over to that one this is North America seven hundred million years ago the other parts of the world are so broken up that it's hot kind of hard to see them but this will become China this will become Siberia this will become other parts of the world now just I'll go very slow here so there goes North America slippin slippin slippin southward to the South Pole at about six hundred million years ago at this time is when we see the first animal fossils and then it begins to move north all the way up to the equator at about five hundred and forty-two 500 million years ago and so we're on the equator here and we have fossils in California that show that reefs at that period of time and then it continues but now it begins to move south again after jumping up see it moves south and then it goes back down now it's joining up with chunks of Europe and hitting in to South America and some of the other continents at 360 million years ago all of these continents now move together into the big continent that you know of as Pangaea Pangaea is well formed at this time by all of the convergence of these continents together plus island arcs and other bits and pieces of continental material spread throughout the world this is the part of time now that I want to talk about the last 200 250 million years watch what happens to California right there this is the California coast nothing at all like California looks today of course because most of it wasn't there so here it goes slowly if I can get it to go it moves a bit at about 210 million years you can see the Atlantic open opening a little bit in the northern part a bit in the southern part and now it's opening and California is moving north and west this is all a subduction zone for the last 250 million years it's a subduction zone with the mega earthquakes and all of the tectonics that go along with a subduction zone and that lasts until just 28 million years ago so we move on the Atlantic opens up here's the end of the Cretaceous extinction of the dinosaurs things are opening but there are no mountain ranges of any size in California or anything else those come much much later and they are part of this subduction process and then finally we see the modern world it's temporary we're still moving as these things have shown with the seismic elements so this just summarizes the last 250 million years of geological time for us that you saw there here's Pangaea there we are things begin to spread and it's this is a the end of the Cretaceous extinction of the dinosaurs there were big sea waves through here in the Mesozoic and there were no big mountain ranges not like the Sierras and then today's situation and it changes this is all subduction from 250 or even before that to through 65 million years to about 30 million years when we finally override the pacific plate and we begin to tear up the continental margin of california so let's see some of these events and how they work so you'll have to excuse me while I move this into the next thing Tana Atwater Santa Barbara has put together a number of these movie clips on tectonics and they're really good this is subduction and the thing to notice this is what goes on for the 225 million years or so even more along our own coasts so imagine this is California at any time during that period of time and what's happening is that subduction goes down here it's sweeping a sediment that's deposited in the trench and on the plates and volcanic material down into the trench and incorporating it accreting it to the Continental edge and we'll see this tomorrow on our field trip all this stuff mashed into the continents so you can hardly tell what these rocks are in some cases and then as it moves on down this oceanic plate under the continental plate it generates a lot of heat and that heat then moves up and forms the Sierra Nevada batholith underneath the Continental margin and so this movie will show that and I'll just run it through once the problem with it is it runs smoothly and that's an average over geological time but it doesn't do that on a daily basis it sticks sometimes it's subducting sometimes it's not subducting and when it lets loose it lets loose with one of these mega earthquakes like the Sumatran one so let's just watch this here goes the the magma up to form these magma chambers some of it escapes in volcanism on the on the edge of the continent here's the sediments being accreted in here and jammed into the continent and as I said that's a sort of temporary or an average view I should say the next of you is the Pacific plate ten you did a great job with this one - gee I used all these computer skills to draw these things and in this view 80 million years ago here's the coast of North America this is the Farallon plate and what will become the Juan de Fuca plate and here's the Pacific plate which today is right up against our continent so this movie shows how that happened now watch the North American plate will override these plates here's this one is spreading in that direction but the North American plate is spreading faster so it overrides all of this and when it finally hits the crest this crest that spreading Center it changes everything in California and it creates the diversity that we see today geologically and biologically because it affects everything so watch this here comes North America there comes the Farallon plate is just about gone at 28 million years ago the North Pacific plate North American plate overrides the Farallon plate and now we're adjacent to the Pacific plate and this continental margin has been ripped apart by transform faults along the San Andreas System and all that happened about 28 million years ago and it is continuing today eventually as they'd like to say Los Angeles will be a suburb of San Francisco and Sam Daly City will be up in the Gulf of Alaska that's 50 million years from now so don't worry about it so let's take a look at it the next little movie clip which shows the details of this Farallon plate and the Pacific plate which is moving in a northwesterly direction the Farallon plate is moving that way and the North American plate is going in this direction the things to watch for here is look at the shape of Nevada and the southwestern part of Arizona isn't even there and California isn't there either and this is just 40 million years ago back in the ESC what happens when the North American plate overrides this crest the spreading center between the Farallon and Pacific plate is that it rips up that coastline and it forms important features like the San Andreas Fault our coastal margins the Gulf of California Baja California moves away from Mexico and a lot of California slips to the north and we'll see that later anyway take a look at this now there goes the Farallon plate now watch what happens when it hits okay there goes the Mendocino triple Junction the Rivera triple Junction is moving down the coast the coast is now moving outward and expanding Baja California is moving northward the whole thing's coming together and now we have the complicated fault system that we have there's the Mendocino triple junction between the transform fault and these other two plates this is the Cascadia subduction zone with the it's hazard of mega quakes all of this then is the San Andreas Fault and then down here is the Rivera triple Junction and then we get back into a subduction zone again where we have again mega earthquakes and then lastly let me show you the details of this California bit so this is for the last 20 million years mainly in Southern California I like this one here's San Diego there's Santa Barbara it's written sideways because this block of rocks is going to twist around San Francisco and LA don't even exist 20 million years ago I mean the terrain upon which they sit isn't there yet and this is then about 8 million years after the collision so here's the Mendocino triple Junction and the Rivera triple Junction down there and this is the seismic or the plate gap there where there is no subduction going on but this is part of California and that's still part of California and these triple junctions move both north and south as this spreading excuse me as this transform action along the San Andreas system takes place now watch this ok there it goes it's ripping up California it's twisting around the transverse ranges Los Angeles begins to appear right about there and San Francisco goes up there and there we are the Gulf of California forms starts forming in the Maya scene it's completed in a couple million years ago and you'll notice a whole bunch of Falls this transverse ranges that you have to drive over the ridge route to get to LA if you ever go there and here's some big lateral faults that are moving in east-west directions instead you want to see that again pretty cool I bet you never thought about that I didn't when I learned about the San Andreas Fault we didn't know about plate tectonics ok so the North the Pacific plates moving Northwest the North American plate is moving also sort of in northwesterly directions so what this you can sort of imagine it's not a head-on collision like two cars running into each other head-on it's more like on the freeway when some idiots in front of it going slow and you Ram him from the behind as he moves across into your lane because the a different angle so you hit them on the left rear fender or something and then you end up with a big mess on your car that sort of looks like that so there it goes again this is really important to get this concept there goes San Francisco Monterey moving northward all of this extends the geography of the Western North America outward Western westerly and Nevada takes on its shape Arizona takes on its shape and importantly California does as well because all this material is getting subducted and transformed northward in this area so let me get on then with some other material now that you have this general background of what's going on you can check these out it's really a nice site to take a look at with these downloads and she has a number of them there that she's worked on to put this together so the subduction one I've mentioned the it's the same website okay here's a summary of what we've seen then here comes the Pacific plate here's the Farallon plate North American plate overrides this boundary here's the Mendocino triple and Rivera triple junctions they move north and south with the lateral slit san andreas system between them and then it all starts about 28 million years ago where this collision takes place and then develops over time and this affects everything the biology the evolution of our marine fauna because we're developing basins in this area offshore deep basins that the Sharks you'll hear about later inhabit that we're never there before during a subduction zone these basins create new isolated habitats the same thing is going on on the land in this subduction zone situation there hardly any mountains and maybe ten million years ago in this situation we begin to see the Sierras rise up ten eleven million years ago a little bit and the coast ranges are doing a little bit of jumping around but it's not until just two million years ago or so three million to the Sears that they really get going up we can see that evidence when we go up the Sears by looking at the volcanic rocks the Merton formation and some other ones that have flowed down the slopes of the Sierras and old river channels as the last gasp of this subduction situation excuse me as it as they were eyes up so this is then is the North Pacific situation here we are with the San Andreas Fault it's all connected we're connected worldwide geologically not just by computers in the internet here's the subduction situation in the north part it includes northern California here's the subduction zones down in Mexico and South to the tip of South America and all this stuff out here the Pacific plate is huge today but it used to be little remember a hundred million years ago it was little and it was the Farallon plate that was so big so all of this then leads to seismicity earthquakes and faulting of California that I want to tell you about and this is just the earthquake epicenters for this 20 year period and you can map the plate boundaries on it I do this in my classes I give the class a map like this and I say draw the plate boundaries and label them and I'll give you a clue the plates are named for the area that they are in for example the Pacific plate is named the Pacific plate because it that's where the Pacific Ocean is that's the Pacific plate so I get the students they get the boundaries I mean everybody's connected dots in the newspaper right no big deal they connect these dots like that and then they label this the Antarctic plate they flunk so where do you think what do you think the San Francisco 1906 earthquake stands in terms of magnitude and is it a great earthquake or not it was about an 8.25 on the Richter scale and here's the 10 greatest earthquakes down in Chile in 1960 a 9.5 remember the Richter scale for every one of those divisions it's a it's a logarithmic scale is 10 times greater in amplitude on the seismographs more energy 30 times the amount of Energy's released there's that big earthquake that's the biggest one ever recorded the second biggest one is the 1964 Alaska earthquake that caused tsunamis this one also caused tsunamis but they didn't get us because we fortunately have a boundary that runs parallel to most of the direction of the wave fronts unless they come from over here uh so this one generate a tsunami this one did too this one killed people in Hawaii and Japan this one sent waves down our coast and 11 people at Crescent City died in this one at Bodega Bay and another one in Southern California Crescent City seems to just focus these tsunamis so they've cleaned up their waterfront did away with buildings and made a nice part there so you can imagine picture this Sunday afternoon they're playing baseball out there having a picnic the subduction zone right offshore there on the subduction zone they're not on the San Andreas Fault it snaps they got ten minutes a huge quake they're running all over the place they're trying to read those signs that say tsunami evacuation route some of them are going to run out into the ocean because the wave causes the sea floor to be exposed and so they're going to go out there and collect some clams and stuff for for later that afternoon and then the big wave comes and hits some and wipes them all out so they need more advanced warning but you can't get it on that subduction zone because they're so close to the coastline there's just not enough time we're talking minutes Sumatra the fourth they've actually revised this now it's the fourth largest earthquake they if it had a tsunami warning system everybody could have been warned because this was two two and a half hours away from the earthquake in terms of those tsunami over here it was six to eight hours if this earth peg actually produced a tsunami warning for Hawaii and for our coast but didn't work very well I was about a nine this is a 9.2 excuse me no that was a 9.2 this is there still revising this one I I saw it was enough you know and it first happened they say was an eight point seven then they upped it to an nine and I think it's now up to a nine point two it's hard to keep up with all this stuff there's this huge earthquake in China and that's an inner plate collision between India moving northward in Asia and that generated huge earthquakes and we often recall that 600,000 people is kind of a normal number to kill in China during one of these earthquakes or if you're over here in Iran in some of these places in Turkey which is a terrible place for earthquakes as well 40,000 is a pretty good number this is what the North American seismograph looked like for the Sumatra quake here comes the P wave and then the S wave and this is the shaking wave and this did a lot of damage and these are places like Boston and Berkeley's on here somewhere but this shows you how it works the seismograms going along it detects the P wave coming in which is the surface pressure wave and then it gets the the shear wave or shaking wave coming in and that's the one that gets everything going I thought you'd like to see what we do here at Berkeley this is a giant eucalyptus tree falling down in Woodside across the bay and they detected it on their seismogram there's the p-wave of that thing falling down and here comes the S wave in there that was about a hundred and fifty foot eucalyptus tree that just fell over so they were a little worried about this I mean what fault caused that earthquake right well no big problem we got so many faults around you know it's just unknown but they figured it out here's one aftershock on March 27th of this Sumatra earthquake this was an eight point seven aftershock I mean the second thing to remember while you're underneath the table or down in those aisles is that there's going to be aftershocks so get more stuff over yet here it is that that's the normal background and then in comes this quake eight point seven thousands of miles away and by triangulating and looking at all these records and that's the reason they revised these things is because the data comes in a seismologist at the USGS or Berkeley takes a look at it and they do a few quick calculations they give you an estimate because they know you want that but then they refine them because a lot more data comes in remember that here's the tsunami generated by that two hundred and fifty thousand people at least maybe three hundred thousand were killed by this tsunami that's about two hours out and then over here's even more and then I wanted to show you this animation of what happens to the tsunami wave as it goes across the world now this is kind of interesting okay we'll try a different version here let's see that working yeah there comes the wave that's two hours out and watch the Indian Ocean this wave propagates across this going 500 kilometers an hour it propagates over to Africa and then it'll start bouncing around in the Indian Ocean so you have several different wave fronts and they hit Africa and other places now notice they're going back they're going back to some entre here but southern some of them sneak around Australia up through here and they come around into the Pacific they come around from the Indian Ocean and go up into the Atlantic and this tsunami affected every coastline in the world in fact here in California we have ten tsunamis a year you probably didn't know that nobody tells you that I'll tell you why they don't tell you that in just a second for this I'll show you so there's the the wave as that wave went around the world it took 24 hours or something for it to get around okay so here's the data on the size of the tsunami in the Pacific 50 centimetres in Chile 19 in Chile another place Pango Pango 13 and down here san francisco was 20 centimeters San Diego 22 centimeters that's about 8 inches or so but notice Manzanillo Mexico 260 centimeters 8.6 feet that tsunami was magnified by the submarine topography and the shape of the coast in those little bays down there in 1995 they had an earthquake and tsunami that killed 41 people in the Manzanillo area we have in fact sampled that to look at the paleontology and to tell the history of this event so these are the aftershocks from the Sumatra earthquake right there for one month every single day after that there were at least even now three earthquakes of magnitude greater than six that were generated by the re adjustments of this thing that suit that event raised sea level or 60 feet in some areas and over a 600 mile or so front that's why you had such a huge wave generated about the only other thing that could generate that kind of a wave with the 10 kilometer asteroid hit in the ocean here's the 1964 mega quake and tsunami with 110 dead people and this is the wave coming out you see it comes down the coast what kind of parallel to it we don't see it we also have high coast cliffs but at the Crescent City because of the submarine topography and other things there they magnify these tsunamis just like they did at Manzanillo so this is an important thing to keep in mind here's a tsunami event hypothetical out of the Cascadia subduction zone right up near Washington and this is what that would look like now we got interested in the history of these things and so we began to investigate using micro fossils by taking cores through the edge of the continent and trying to reconstruct the history so that we could understand how often do these mega quake events take place and do they generate tsunamis and what's that history we got some money from the university's Pacific Rim project and we went around the well they cut the money in half so we cut the area in half we only did the west the eastern Pacific not the western Pacific or we probably would have been in Sumatra the idea the way this works is that s subduction takes place it drags the edge of the coast downward like that this stress that's being built up by the subduction and the dragging down of the edge of the continent is reversed in omega earthquake and it goes back up in a few seconds we can see that in the fossil record of if we drill down with cores in these marshes and mangrove swamps and then by analyzing the micro fossils that occur in there we can tell you the environments and how much motion there was on this upward or downward trend and this is the sort of sequence you see essentially there subsidence going on as the Continental margin is pulled down the submerges the trees the trees die and then when there's a big earthquake they may bounce back up here's some small subsidence between maybe two three five or ten years before the major fracture we've discovered a precursor event that isn't a pre predictor but at least a warning that the big earthquake may be coming so there's a precursor event there's a major earthquake it lays down a layer of sand in a tsunami across the the place and then by taking a core we can see that sand and the organisms that are in it the organisms that come in on the tsunami are different than the ones that live there we can tell this very simple and so on the way we do that is we drill a core through a marsh here's my colleague Dave doing that here's the ghost forest as they call it that's been submerged under the water sea water as the edge of the continent is bent down and you see these and so we went around and we sampled for the 64 earthquake we looked at the Oregon coastline we looked at Manzanillo and we looked at air at North Island which is on a subduction zone New Zealand there's Sumatra this is what we'd like to do this coming summer maybe these are the organisms we use they're called foraminifera they're single-celled organisms and they're very sensitive to within five centimeters of tidal height so we can tell when that's coastline goes down we can tell when it snaps back because these organisms and the snap-back are no longer there because they need marine water in comes a freshwater assemblage of other kinds of organisms that we also detect so we can see these events let me show you what we did not in New Zealand before we get to the other areas here's the subduction zone this is interesting because it's a lot like California here's the subduction zone with the Pacific plate moving underneath north island and then it transforms along the Alpine Fault which is very similar to California's San Andreas Fault when I was a graduate student we studied the Alpine Fault to give us insight into what was going on on the San Andreas and then it joins up with this other subduction zone so we went here to Hawke's Bay and in Hawke's Bay this entire area was hit by a mega earthquake in 1931 many people were killed but what's really important is this Bay this is the bay that occurs right near Napier on this coastline and this whole thing was a lagoon big bay with several meters it was at least a meter deep and in 1931 on that earthquake in a matter of a couple of seconds it went up a meter meter and a half and it all drained out and the bay was no longer and now up in this area they have this is a great this is like the Napa Valley of New Zealand and they plant vineyards in here and there's one up here I love this place it's called crab farm Vineyard and the reason they do it the name is because every time they dig a hole to plant a grapevine they find a fossil crab from before 1931 isn't that cool so we drilled a bunch of sites in here my colleagues down in New Zealand have worked all this material up and we see tsunami events we see things going back 3,000 years and we have some idea of that history there and it's similar to what we see in Anchorage at Girdwood and the city of Anchorage and down here at neat arts Bay in Oregon where we did the same kind of sampling this is what we you see in Alaska here's some is total organic carbon bunch of other things the thing to look at are these organisms over here these are different kinds of freshwater organisms and then there's subsidence after the quake this is all pre quake stuff sometimes it works in in Reverse so we went into subsidence here's marine organisms and that's the quake event we see maybe five to ten years before that's some kind of precursor to this a little bit of subsidence we still don't know what's going on we're not seismologist we're paleontologists and geologists but our seismo people are really interested in this now we see the same thing in neat arts Bay a precursor we see some sand material here's the sand coming in across this that's the quake disposition of sand probably in a tsunami so here's sort of a summary those diagrams are a little hard to read here's in Alaska this is what we see in our cores there here's the 64 earthquake we see maybe a 10-year precursor on that event in one of three sites at 1,800 years before the present time we see another precursor event ten years before that and then a mega earthquake here's neat arts Bay three hundred years before the present there was a bit mega earthquake we see the sand come across we don't think that sand was a tsunami doesn't have the right fauna in it it had a precursor event here's another one 1670 big BP that sand has the tsunami fauna in it so this was a big tsunami 1840 same thing with a precursor another precursor at 3,000 so this gives you a history of how often these events strike this coast we could do the same thing in Sumatra and save them a few bucks because if it takes 300 years or a thousand or 1300 years to generate enough stress on that Sumatra subduction zone to create another tsunami and we could see this in the fossil record then they could relax take their time build it up properly get the tsunami system in order okay I want to move on to California where we we get these tsunamis up here at Crescent City but the big hazards are the San Andreas system so let's take a look at that in the last you moment's here's the big earthquakes in California starting in 1906 8.25 recalculated from data they didn't have a Richter scale at the time here's a big one there the Imperial Valley earthquake these in yellow didn't have much damage because they're mainly in remote areas here's the Tehachapi earthquake in 1952 a 7.7 it did damage in Los Angeles I even remember it as a little kid the San Fernando earthquake in 71 not a big earthquake the aftershocks in Sumatra are bigger than that and this did did much much damage to the freeway systems and everything else down there Kalinda the same deal here's Loma Prieta you know about that one because you were probably in it right how many of you were not in it I got you didn't I a few I was in it over here in another building I thought it was about like a four on the Hayward Fault right over here but boy I was really surprised I went back to my office in McKown Hall and I thought after sitting there for an hour so gee I wonder if I was right on my guest went down to the seismograph there and there's a huge crowd standing around it they're talking about buildings burning up and everything wow I missed that one didn't I and then Northridge lots of lots of damage there too so here's the ones in the faults in the Bay Area tomorrow on our field trip we're going to examine the Hayward Fault we're going to cross over go up this way look at the subduction zone complex look at the San Andreas in Tomales Bay and then come home and hopefully there won't be any big activity there tomorrow but these are the faults that are worrisome the Hayward Fault in the San Andreas and I'll show you right here the probabilities of earthquakes on each of these faults that gives us a total probability in the next 30 years of a 62 percent chance of an earthquake greater than six point seven six point seven does some damage here's the Hayward Fault 27 percent San Andreas in this area 21 percent in that various area to area and some of the other ones are interesting these these over here are not as active 3% so on Calaveras down here's 11% san gregorio 10% so the biggies are still these two there is a group of people that say the Hayward Fault and I know this because I live on it right about there it's creeping all the time little ones twos threes you can feel them especially at night when you're lying in bed around my house can't feel anything during the day this is a modified McCurley Mercalli intensity this shows damage and this is recalculated for the 1906 earthquake and these are huge areas of damage and you can see where they are and the damage extended along sort of the trace the fall this is the break of the 1906 earthquake and this has just been published this month I want to show you a few pictures of what happens in these things and then think about what you would do and how to deal with these situations this is San Fernando 1971 major earthquake it destroyed the freeways look at that it just jammed the concrete like that it snapped up it took a few seconds here's a guy he's driving along the freeway 60 miles an hour he sees that crumpled he hits his brakes and he launches himself into the air it happens fast folks how many of you were driving during Loma Prieta what do you think what's going on with your car yeah how about you yeah I know my wife said she said that she thought she had a flat tire too but she kept driving said you should always stop if you think you have a flat tire this guy wasn't so lucky this is what was the name of this hospital there olive View Hospital where right this is the Olive View Hospital this is the stairwell goes up here the built this building was okay this however was the first floor of this building which is now about three feet tall this is what will happen to us and I will be under there for seven days with my bucket I don't know what you guys are going to do but I'm not coming out but I will have my pick so this this is the status then that you can expect to have your emergency buildings in this is the reason though that we're going to have to wait seven days these are the ambulances how are they going to go get anybody be self-sufficient and remember these earthquakes is particularly bad the worst nightmare scenario for me in this area is an earthquake on October 10th as the Santa Ana type winds are blowing out this way the houses go down the water heaters explode with the gas and we have another 1991 fire and you can't get around because remember in Loma Prieta that earthquake snap the tops off of the redwood trees and they fell down and blocked the roads and the roads were all messed up you cannot rely on the government to help you because they can't even if they want to because their ambulances are under something like that there are other ways around the problem you can pray let me just quickly end here with our own campus where you're sitting today this is the trace of the Hayward Fault I assume you're laughing because you're really feeling a little uptight about this our building is located right about there where you're sitting in this area this this is from a bag there's the website and they've done this so this is the hazard zone the big hazard zone it's all a hazard zone down here it's really bad why is that Bay mud Bay mud these buildings have all been seismically retrofit this is our building Roy tells me I talked to the seismic engineers when this building was rehabilitated for us that's what I call it reconstructed and they said it's seismically the the strongest building on campus so I'm talking to Roy you know what are you going to do in an earthquake I said or I said I'm going to you know run out get my car and go away back to the guns and stuff in my house and Roy told me don't do that because the walls are going to fall off this building they'll just go out like that because the walls are 19:31 and these walls inside have been reconstructed in 1995 this is the campus in 1907 actually but in 1906 this is South Hall it's still here they've rehabilitated that one in its seismically good bacon Hall is gone North Hall is gone those agricultural buildings are gone but these withstood with some damage the 1906 earthquake and so we have this tradition and the Campanile has been fixed up but you know I don't trust these guys I tell you I remember they had a big earthquake in Caracas all the buildings fell down bends whele said oh we built California building codes here's Memorial Stadium we're going to see this tomorrow not with the drill team here but what we're going to look at is the Hayward Fault which runs right through there it doesn't run up like that but the crack that we will see tomorrow runs right through section KK and we're going to go look at that it's offset and the campus has put a big steel plate there to hold the fault from moving up the stadium apart it's now bent about that far so it goes like that but the Chancellor is working on getting us a hundred million dollars to build a new stadium I wonder where they're going to put it some people have suggested right down here at University and Oxford I think it should be down in the bay here's the summary of losses they estimate for the Berkeley campus with an occasional fault fault movement on the Haven teaser Hayward faults 720 million dollars that's not a big deal I mean the earthquake there's a rare event a billion seven hundred million and here is a very rare very large event like the 1868 earthquake two billion a three billion in total three billion dollars damage to the campus when I was telling the Museum of Paleontology group this one of the students said well they have a plan to move the campus after the earthquake I mean you know that's probably what they'll have to do because they're going to have to rebuild a whole damn place but where are they going to do it they're going to build it next to a fault almost anywhere I think they ought of rebuilding Kansas so all of this stuff that I've been telling you relates to California's geologic and biological diversity the subduction and accretion and transform faulting have created California the way we see it the subduction has given us our mountains the Sierra Nevadas the coast ranges the offshore basins LA was a basin there's la a basin Santa Barbara was a basin Santa Maria these areas they were all basins that were deep like six thousand feet deep in the geological past you've seen how that has happened and how its transformed into what we see today that action is continuing and we'll see some of it tomorrow on our field trip that leaves and goes in up in this direction and back to Berkeley so thanks very much

Channel: University of California Television (UCTV)

Views: 44,101

Rating: 4.6913581 out of 5

Keywords: earthquake, fault, geology, biology, California

Id: QzdBx9zL0ZY

Length: 57min 50sec (3470 seconds)

Published: Fri Feb 29 2008

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[u/alllie]

Jere Lipps of the UC Museum of Paleontology & Integrative Biology at UC Berkeley explores California's enormous diversity of geology, landforms, and biology which has been shaped by more than 200 million years of seismic activity. Series: "Uniqueness of California" [9/2005]