Prediction of the world : Where We Stand in Earthquake prediction । Prediction 2020, part-1

Prediction of the world. Prediction 2020

Prediction of the world
Prediction of the world

Thank you very muchfor joining us prediction of the world, prediction 2020.
 tonight. I really want to thank Meredithfor always doing and making this really nice,elaborate introduction that are at the same time humblingbut extremely flattering.

 So really, really appreciate. So tonight, I’m going to speakabout a topic that’s actually quite new to me, but Ithought it was a lot more relevant to humanity.

 Population is howwe can or we may or we may not be able toactually predict earthquakes. And if you fly to the SanAndreas or San Francisco and you have yourlaptop open and you show seismogrameverybody will ask you, can you reallypredict

Prediction of the world. Prediction 2020…

 When is the next big one? And every time we tend to, wehave to say carefully that we probably cannotpredict earthquake, because we can have liabilityissues in saying wrong things.
 But I’m actuallynot losing hope. Recently, we’ve harnessedso much data and we’re making more observationsthat I’m actually– I think that one daywe’ll be able to do so, but I wanted to gowith you and show you what are thetimescales involved in and where it actually matters.

Prediction of the world. Prediction 2020

 And so, this is aquite old photo. It’s taken afterthe 1906 earthquake. It’s a fault that runs throughthe city of San Francisco. So that image that yousee here, of course,
 it’s older constructions,it was very dramatic. Most of it was dueto the fire that started after the earthquake. So earthquakes do generatea lot more hazards that are just coming out after that. The other type of– When we think aboutearthquakes, we think about this previous photo.

 And what we see hereit’s mostly damage that is sudden rightafter the earthquake. It’s people dying,it’s building collapse, it’s highway collapseas you mentioned. And these are iconic figuresof what earthquakes are.

Prediction of the world. Prediction 2020

 What I also wantto point out it’s not necessarily thecasualties that we refer to, but it’s also thegreat economic loss that are a componentwith these earthquakes.
 Some countries have reallya lot of trouble recovering from those, such as Haiti in2010, Japan in 1994 and in 2011 was hit twice badly. So there’s a lot of economicloss due to these earthquakes. Earthquakes are alsothe way that the earth has to form landscapes.

 This is a photo from 2010,another big earthquake in Southern California. And you can seehere very nice fault scar that’s not been erodedyet and a geologist for scale.
 And if you can seethe hills behind, you actually startunderstanding that earthquakes are the cause of the buildingof the landscape around us. And I want to zoom outand look at the Earth.
 And I can tell youmost of the topography that we see here isdue to earthquakes. So what you can see here is the[INAUDIBLE] image topography map.

Prediction of the world. Prediction 2020

 We are looking over there,centering around the Pacific ring, because we have a nicedistribution of seismicity around it. But you can see there’s alot of texture in this photo. It is just showing you thatthe earth is very dynamic, and actually the earthquakesare a system, a mechanism to deal with this.
 So the plate tectonics isbasically all of these.
 They’re not totally rigid,but we can simplify the system as a very rigid plate. They are surroundedby those zones, that you can see thetopography quite clear. You can see thezones here and here.

Prediction of the world. Prediction 2020

 The topography shows you thatthis is the Pacific plate. It’s surrounded, it’sbordered by active faults, and the San Andreasfault being one of them. So if you look at the Earthat this scale you say, these are lines. People like to see fault lines.
 It’s not lines. It’s the surface, it’s a volume. But we can simplifythem as line, and then we can assume thatmaybe earthquakes are on it. Earthquakes are indeed mostlylocated on these lines here.

 So these are ridges, this isthe San Andreas fault system, this is Japan. And you can seethat globally, you may have distributed seismicity,but all those stars are representing where most ofthe big earthquakes are. So crudely speaking, you knowthat at boundaries of plates you may have earthquakes. Of course Oklahomais showing up here, not quite but the [INAUDIBLE]that you can have seismicity. But on to thefirst order,
 if you want to know whereearthquakes are, it’s usually on thoseplate’s boundaries. Now if you zoom into this boundary, it’s actually amore diffuse system.

Prediction of the world. Prediction 2020

 These red linesand the black ones are representing maps faults. And you can seeit’s not in line, it’s not necessarily straight. It has curvature,
 ithas nice delineation. The dots here areshowing the seismicity that we have that actuallyseems to correspond to those topography features.

 So if we want to knowwhere faults are, traditionally what we lookat is the past seismicity in these catalogs and lookat where seismicity is. So this is San Franciscoand the biggest earthquake was along this fault. Andyou can see for most of it, there’s actually noseismicity at all.

Prediction of the world. Prediction 2020

 So if you rely on these catalogsto know earthquakes are and try to predict it, you are actuallymissing out a huge part, because here you canhave a large earthquake, but you have any seismicityto understand it. So I spent my PhD,
 youknow, somewhere over there and had zero earthquake for 5and 1/2 years, which is good. But sitting thereit was interesting. Faults can be very quiet.
 So to deal withthis, geologists, they dig big trenchesthrough faults and they look at thetexture and the composition of the minerals in rocks.

 And they try to datethose rocks and then to try to find thehistory of the faults and how manyearthquakes there were. So this is an example onthe Wasatch fault in Utah, which borders the SaltLake City to the east.

Prediction of the world. Prediction 2020

 And so, if you actuallylook at those rocks and you make timehistory of them, you can find whenearthquakes happen. And I’m showing you the bestexample we have of this. So this is New Zealand. And I don’t knowif you can tell, but there’s somelinear feature here. Linear features are not natural. They’re really caused by faults. And this is highlighted herewhat we call the Alpine fault.

From a French perspectiveit was like, these aren’t all the Alps. [LAUGHTER] – [SPEAKING FRENCH] .
 But New Zealand is like it. They also make excellent cheese,so they have a good excuse. But so basically,this is the Alpine fault. It’s a quite fastfault. It’s also heavily– There’s nice topography to it.

Prediction of the world, Prediction 2020,

 And if we trenchthrough it, geologists have found a niceseries of earthquakes. It’s also nice becauseit’s not really populated, so it does not causetremendous damage, so we can use the word niceto think about earthquakes. This is the dates ofthose earthquakes, in thousands of years.

So if you look at theinterval between each of them, you make those plots here,which look at the recurrence interval between
earthquakes,and you see that they’re mostly around 300 years.
 And for all of these 10to 20 year earthquakes, every 300 years youmay have an earthquake. And so the last onebeing in the 1700s, we’re close to the end of thecycle for this earthquake.

Prediction of the world, Prediction 2020,

 We think about earthquake cycleshere because every 300 years, we can have an earthquake. So bingo, we should be ableto predict earthquakes. Of course, I’m notgiving you this talk to say yes,
 we solved that. Many faults do notbehave like this. This is a time series hereshowing the lifelong time series of the faults.

 These [INAUDIBLE] are showingyou when earthquakes happen. These are several faults.

So the predictabilityhere is not strong, because we haveclustering of events and we can’t evencontrol those clusters. So what happened on a fault? We think aboutearthquake cycles, because an earthquakehappens, it heals, it’s in betweencycles and hit again and it’s supposedto be periodic.
 Scientists today do notreally like the word cycle because of this irregularityin some of the fault systems.
 But I’d like to justemphasize that it’s just a very, if we think aboutit, a very simple model. You can think aboutthis model where you have a spring in a handle.

Prediction of the world, Prediction 2020,

 You have a sure phase that couldbe rough or smooth as you wish. And then you have ablock, and you pull it. So that if you have elasticityin your string here, the block is notgoing to move as you pull until it’s tootensed, and then the block will slide it toward you.
 And so this effect ofincreasing the stress loading on thestring, and then slip, and it sticks, and it slips,and so on and so forth, is the fundamental viewof earthquake cycle, where you increasethe force the plates are moving at a somewhat regularpace and then it’s locked.

So if we modelforces in the earth, you can say it’s a constantforcing,

Prediction of the world, Prediction 2020,

 constant slip constant forcing, constantslip, this is the ideal case. We have in the UnitedStates one fault that seem to behave like this. It’s in San Andreas faultin the Parkfield area and it was soregular in the past.
 These are years of occurrenceof these earthquakes. Every 20 plus years therewas a little magnitude 6 that would occur on this fault.So these are the earthquakes series and you can look atnumber of earthquakes and time. You draw a line andyou predict when the next earthquake will go.
 So the prediction was thatbetween 1987 and 1983, we should have an earthquake. So the USGS deployeda lot of resources around Parkfield toinstrument the fault and to capture the full cycle.

Prediction of the world, Prediction 2020,

 But the earthquakedid not happen. And I think a lotof the seismologists completely lost faithbecause it took many more years for the earthquaketo actually occur. And so I think when big eventslike this,
 either like Tohoku or all these events where wedon’t expect them to happen, it’s very hard forseismologists to react. And so I think because ofthat, a lot of the seismology has been going awayfrom prediction.

So let’s think aboutthis time theory that I was just drawing you. We have the earthquakeat time zero, we have what happens beforeor in between earthquakes, and then we havewhat happens after.

 So here, I’m showing youthat between years to months to second beforethe earthquake, this is the phase that wecall a nucleation phase. We are at the end ofthe earthquake cycle, something is happening, wewill have an earthquake.
 We just don’t know when t=0 is. What happens after isthe earthquake ruptures. It’s not and[SNAPS FINGERS] instant. It’s not a snap likethis, it takes some time. So we have a few seconds totens of seconds, during which and after which all theshaking, the ground motion goes, and that’s whatdestroys the building.
 So the prediction ofearthquakes within years, I’m a little bitskeptical today. And I would say thatprobably we may not be able to do thatanytime soon, mostly because we do have manyyears in our records.

Prediction of the world, Prediction 2020,

 But let’s look at nucleation. What happens between months andseconds before the earthquake? Unfortunately, all ofthese precautionary phases are seen or detectedafter the earthquake. So far, we haveseen those phases,
 but it’s always after goingback to looking at the data. So in 2011, March 29, 2011,magnitude 9.0 in Japan.
 This is a map of Japan. This plot is showing you withcolors the amount of slip on a fault surface. It’s dipping like this.

So basically inthe middle, that’s where you had about15 meters of slip and then nothing in between.

Prediction of the world, Prediction 2020,

 And these colorsare showing what happened before the earthquake. And so using dataon shore, scientists have been able to look at howmuch slip, very slow slip, happened years beforethe earthquake.
 This line here,this time series, is showing you what a GPS wouldrecord as a function of years. So you can see wedon’t have that many, we have maybe a fewdecades worth of data, but not that much more.
 And if you removesome of the effects, you can see that there is thisnon-constant but accelerating phase of displacement, andthis is mapped into the fault.

Prediction of the world, Prediction 2020,

 And so we have thisacceleration of slip, it’s very slow andsteady, but it grows. And we can detect it bylooking at years of data. It’s very often afterwardsthat we notice this. If you look at the foreshocks.
 Foreshocks are earthquakes thathappened before the earthquake, the main shock. Foreshocks are onlycalled foreshocks after the main shock,so it’s hard to use them as a prediction. What I’m showing youhere is three earthquakes that happened inSouthern California.
 This is the El Mayor-Cucapahearthquake in 2010. I have sensors actually nearby. And my husband actuallywas on a Jeep on the road with GPS deployingsensors at the same time. These are twoearthquakes in the 90s that happened on the easternshore zone in California.
 These are showingyou the magnitude with time of the earthquakes.
 The black ones are, yousee the aftershocks. because they happenafter the main shock, shown with this cross.

Prediction of the world, Prediction 2020,

 And the red onesare the foreshocks. Do you see any pattern? No. There are someearthquakes, but are they foreshocks, aftershocks ofthe previous earthquakes? We don’t know.
 So these are kindof the observations. In the lab though, if you wereto make earthquakes in the lab, the system is a lotmore predictable.

Prediction of the world, Prediction 2020,

So I would say that whathappened in nucleation, I think maybe we rarelyobserve them, usually for large earthquakes. But we have observed some.
 So I think lookingback at the data, we may have hope to studythose phases a lot more. So now, the user,
 theperson, the surgeon, the eye surgeon withhis laser is saying, when should I stop the laser? When is the shaking comingif there is an earthquake? And so, I’m notskipping this phase, I’m just saying, who cares aboutwhen the earthquake happened?
 I really care just about theshaking and how much shaking. And this becomesactually a different side of seismology,

 which is verymuch oriented toward operation and user and, you know,what matters for people is really just the amount ofshaking, whatever earthquake style we have. So, if these are yourscience question, then we can lookat other things.

Prediction of the world, Prediction 2020,

 So I want to focus therest of this discussion on what happened during therupture and right after, and how can we help theearly warning of the shaking. And this is– I’m an amateur at this, butI wanted to show you briefly what the system of theearthquake early warning is about.
 And I heard todaythat the funding will be continued, whichis nice when you already spent 20 millions ofdollars, to have it finally an official earthquake earlywarning system in the United States.
 Mexico has one since the 90s. So we’re developing– Scientists are developingone in California,

Prediction of the world, Prediction 2020,

 and we’ll see theWest Coast in general. And the system is as such. Phones and internet isfaster, propagates faster, than seismic waves. That’s where you win. That’s basically it. If you have an earthquakethat happens on a fault, some ways will propagate. The first one, the yellow one.
The first one is notthe most damaging, but he carries alot of information. So what you want is havingsensors close by the epicenter. Then you have more to say well,this is an earthquake and not a car driving by, so you may need a few sensors for this.
 But then the information is nolo get sent with seismic waves, but with phones and communication like this,
 so then the data gets into the earthquake [INAUDIBLE],, and then there’s adecision-maki get module which says, this will be the size of the earthquake, therefore this will be the shaking.

 Should we alert, yes, no. All of these modules are quite complicated and elaborated. And then it gets to the people.

Prediction of the world, Prediction 2020,

 And there are apps,you can have it on your phone that would tell you the level of shaking of intensity of such will arrive

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