GeoSci.xyz GWB Lectures, 3 Feb 2020

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From YouTube: 2020 02 03 Day1 Part4 Background1

Description

In this video, we present the basics of the DC resistivity experiment. We then show a 7-step framework for applying DC resistivity to a particular problem.

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We're gonna talk about this later. Don't worry.

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Anyway, the person we're trying to find this resistivity and then find the wrong types, so we can't find the water finally.

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Which are maybe Oh rough type of tell news. Irish are may be.

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And then, with it run time after that, water yangjia.

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Picture of and then matching those units to the expected resistivity value, Romulan.

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Honey resistivity, yet damn boy, oh no come on Tara, thou, Romeo mummy in a message: Nettie outcome yeah! Yet anytime people yeah the attending and they I don't know.

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Okay, so, following this model target set up current charges potentials we can look at. We can take a look at more of the details.

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To set up to parents to charges to potential taken zero Deepika have a security comment, so.

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Say the aquifer here.

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Is it's just it's just.

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A very thin layer.

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Goes infinitely out there.

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Together I put five yeah Mon yeah Mon.

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The V form on treating your body.

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A paulina in a dilution so.

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Horizontally, everything is the same: there's only a difference when you go down. Oh.

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My new and then isn't it, who knew each other back then that fine with live, is on an ample Brooke for our time. Who is she yeah.

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It has a low resistivity.

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Let's say 100 or 5000 meters and then it's surrounded by rocks. That's high resistant, perhaps 500 meters, I'm.

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On phone mom unit, ID, Navona I, might see the amplifier eyes are up, go on resistivity its native unanimously. Now that the I love she she made that way. Oh, my god, hi again, I, don't know tell or not.

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And then, when we have the 4 electrodes.

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We do this four times we inject the current. We can do some modeling, it's a mathematical modeling and see that the current it largely it stays inside the low resistivity later.

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I not gonna, move the electrodes legal like mu yet alive. You know Nessie jumper,.

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Like this are never I guess it tell me ie.

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Interested it's not be showing the current density, its measured in amperes per meter squared, so the.

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Of current flowing through an area.

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What is the union against reason.

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Finding parents.

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And an economist.

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How much criticism.

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In a the wife, Anna.

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So see this area is green. It means there's a lot of current concentrated in this area, so.

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I say: I'm sorry I'm on yes he's down the pool. You know Sabido today as.

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You remember from the other slide when we have a change in resistivity. We also, we also have charges that are accumulating I'm.

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A resistivity down lobbies on here my charges, theater.

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Okay, so then it's just.

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Imagine there are a lot of.

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These plus and minus charges inside and.

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What's our idea, the way mother plus two without me right for not just economic.

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And then, if we measure the voltage along this profile- and this is what we will measure for.

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Charges steer the pole takes.

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Little tiny return on me, yeah.

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So many of you remember because Coulomb's law for the voltage it's V equals some constant times the charge the amount of the charge Q divided by the distance. So.

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It's it's like this.

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I wouldn't go into it.

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Okay, well, basically, so so this is a CA B or a M and B. So we measure the voltage at em. It's this value. We measure voltage and is this value, and then we take the difference. Ii and.

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Ends with the pointy do not time daddy, so M the end, the rifleman. If you look then at that point, I'm and.

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Then is this equation based on all the distances between the points like.

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What's the equivalent in the equation they fell on it.

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And then we can find the resistivity ro by taking a potential difference between em and then dividing by the current times. His number juice currents, time and.

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So it's kind of hard to see, but all these all these numbers here- that's all G, so it becomes V equals Rho by G. And then, if you divide by I G and this Rho equals V over.

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This G is a it's a geometric factor, so it will change depending on how far apart these electrodes are spaced natural.

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Yeah quality right, G, gallop down.

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Now you notice that it's not just row, it's grown with a small a so this is not just resistivity, we call it the appearance. This is stability.

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Row together that row, eight.

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So we call it an apparently sympathy because it's kind of like this is average okay, say look over here when you make the measurements there's the question. Well, we're gonna do a resistivity, but of which part is it? Isn't this part? Isn't this part? Isn't this part? We don't know.

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Resistive di Nakata I am I'm tiny about it. Yeah, maybe of Pamela the argon along here.

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This is like some kind of average of this layer and this layer and this layer I.

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Bentley is average every layer. It was acting that young yeah that's.

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What we call it.

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Sound very apparent.

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No such thing as a stupid question we're all we're all trying to learn.

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Us intellivent-asv that still in Bihar, she managed to share with our motivation.

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We're going to look at this 7 step framework.

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In a bit more detail, so doc discussed it in the morning. The first step is set up, so you know we collect all of our information. What are we trying to do? What is Tomaso.

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Pantera set up set.

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Than I achieve nearby sedan in Israel information is some sound, a zoo.

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Zombie, too much of a knife. Finally, as.

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Drought shock for you or not step back, okay and then.

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The properties well, our property, obviously is so.

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Good udi general properties, probably is about man. You see permits that work, so they didn't have your electrode. This is stupid and.

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Many different ways that.

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We can set up the survey, for instance,.

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Maybe mmm there many different ways.

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Serenity, mother Navarro, how many talent with pharmaceuticals, anatomical, APA mental.

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General salvation and then for our case, the data.

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Going to be some kind of map.

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A teen area to Allah may go a mother, resistivity diet, America Zara, Montilla genetic engineer, electron on my name.

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Will process the data and for this particular method, mostly that means disputes to physical inversion.

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Decided that that process anxiety to physical method, without you know my process, love that reverse Ladakh. Once.

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We have the inversion, we can try to make kind of geologic or hydrogeological trepidation.

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Now, someone's our interpretation.

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Then we can do a synthesis which is kind of like a big review or evaluation.

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Can try to integrate for combined geophysical.

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Into other disciplines.

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Much it's a protector quality be tied to physics, they advertise the opinion in a Taha, the founding family domain, meaning we probably want to.

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Compare with previous resistance precedence if I, if I did a surname.

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You know mo dog Buster, but maybe.

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This year we go back.

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To mood on the.

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That shanty my book, you know, look at how that.

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I never bother, listen to me young man and then.

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We asked well after integrating Wallace's all this information. Are we happy with results? If we're happy, then that's good, we're, not happy, then you know we can go back to the first time.

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Alopecia peace Americans are still I'm a goner Oh.

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Mortality dinners in the time.

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So, of course, our problem is aquifers in one state.

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No I, don't I, think you could just sort of flip through I. Don't think you need to go into detail, will come will come back, but you just mention like which, like which step were actually on. We have to set up. We have.

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Ci by no baby devil by didn't after the knocks in today and two different that all chat with water setup step.

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This thing the goal is using these Tiffany find.

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Idiot Oprah netday aquifers will shout it out and.

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Then physical properties well DC resistivity, and then we said that our our target is this freshwater, which typically has business that the 50 to 100 or 20 to 100 meters. No.

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Talking about as I need to vote no but resistive this, you mister mouth, and if they ask John or me that she did pity a freshwater shock.

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So it's interesting because 50 with the 100 that can either be low or high, depending on what is surrounding the freshwater.

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So ain't my husband at the osmotic wahoo she liked what she does. Women I do win toilet yeah busy day for material yet resistivity other. haha She.

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The one kind that is very common is the celebrity ugly.

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That's where the potential Electro's M&N are quite close together.

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And naturally, subunits are.

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So I believe the DRG has they.

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Two system, so you can do it in the.

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Of course, for us, we're going to be using organ system is Cisco or oneplus, which can.

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Do tunisia face justice for r1 plus become um a duty to Langley.

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Now, for this case study the data, so this was taken with the Cisco- are.

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You have access to the a.

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Cuz we missed it out in there I'm sure we have so.

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And x axis is a B divided.

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So like baby and.

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Pink, which is trying to straighten all that out. This is your a.

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Believer in it.

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Like the spacing yeah.

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Point baby, which is.

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Like a distance distance, distant of a be divided by two, so.

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See you here, the distance was.

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The distance is 10 to the power 2, which is.

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Is 10 to the 5.

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Be but a few fools you mean eventually 100. Of course it means the distance between yes, like a P, so.

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Okay, so what we see here this is very small, then you have high Mississippi, but then, when.

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The distance bigger you have lower well.

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Is what I know this is still yeah yeah.

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Know why wait a minute, okay and then it GU I got that up. There is.

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So when you have a small separation, then it's only very the current will only go very shallowly, not very deep. Okay.

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Thank God in it. So sorry, Hank, Nick, Oh, God. 'my name is li mochou, a lot of heart and think they came a.

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Long way, next, one.

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This tells us that somewhere deeper, there is a lower resistivity area which maybe is not.

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Common as a linear power name, we Katara and Nettie Guarico guess these are Mexican authorities, a magnetic Iranian, gamma or low resistivity Sheena study area and.

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Then she'll were closer to service and there's higher visa seventeen, where maybe like, go elaborate.

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So they tapped of a more technical that makes you know. My name is really, however,.

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How so, how deep exactly is this you.

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Know this is a distance.

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But it does not tell us how deep is this aquifer so to find that out, we need to go to the next step.

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Magnetic Juarez roger area, these a Medina mean I, did another thing said la.

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So that's the next step.

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For us is inversion, table.

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Stands out inversion with your money.

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So this was played.

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Me that's a smooth modeling version, but it's it's in 30 layers or something.

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This is what we call a smooth inversion and it has many different layers in fashion.

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This is the particular process.

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Inversion isn't evil smooth inversions? They are denying how.

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I think we go into details about this. You can see as we go deeper.

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Acidity there's a small.

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Netwok imagine.

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Of minimum Bernays- oh yeah, maybe not.

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The interpretation is that this low resistivity zone number one is.

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About one year so much in it does, this is stivity native and the ISO much at all. They named Tatiana and.

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Then load resistant zone number two, maybe it's the fraction aquifer.

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Nominate Judea resistivity near any other, a fracture at for $5.99 for anyways.

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Remember that we said earlier, you had this table and we thought that fracture or whether to bedrock is in range of 40 to 400 meters out.

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Evenly outrageous, this is diagram, cannot it. This is about.

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About 30, we know how to read above.

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Ultra-Radical new palace of america.

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So 10 20 30 40 50 60 70 80.

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So this is approximately 30.

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It's inside this range.

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Then, as we go much deeper, then the resistivity gets higher approaching 1000 10.

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Into 3 things a lot longer, whoever system here so.

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10 to the 3 over that could be something like igneous rock.

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But with no no pressures so.

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Not as I said before mr. meanwhile.

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Your appetizer, the other mechanic with.

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Of course, actually actually find out what kind of rocker waters that are, then we need to drill.

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Yada yada, but every time you know, she'd have any any tamashii that form with the video meter. You can do out.

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So the synthesis final step but, as I said, to really find out what is happening, whether our interpretation is correct. We need to drill the hole and prepare the information, so we do not know the answer.

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So statistics, kavadis or bad result, apology, there's no drama number to our example. You know it's a friend.

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Of pyrimidine fiamma's.

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Rolling in the tradition.

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Team at the Amazon, these.

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Ok, so now we're going to apply the 7 step framework to another.

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Think every team.

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2018 in constantly.

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Each in this and then another cave of zip, our IQ positron, sir three thousand thirty thousand Oh.

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This this machine in 2018 was a lot more limited, but we didn't have any support from an organization like Jim scientist about borders, so this was the first.

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Year that Wow, how long's she get that one? If we don't talk, did you physically pathetic.

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So, of course, the purpose of the survey first was to identify it if the instrument is working, so we can do some.

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Japanese Japanese international cooperation agency JICA, they did a survey in one village in between culture. It was five kilometers, apart from.

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Being internship, the.

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Man p.m. you never.

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Check that had a location in the tank I actually so.

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We couldn't go because.

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Results are why.

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Yeah- and this is just holding up a hammer.

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Physical properties, while you seen this before okay public survey so survey, we used, it was a wonder rate what it's called when ur irate it's like a bit different than some Virginia. It's urgent, though.

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Why we're not really savvy Rosati when I read it.

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So basically, in the.

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Winner array, they.

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Just the distance between all the electrons same so safe distance so and.

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When I read minds are naturally I will bow.

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B

And here's the data that we obtained on top of a village again. This is a it's not the same as a B over 2, but it's some kind of spacing and then here we measure the apparent resistivity I'm.

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Not parent resistivity, you are well, we young. You know that you change, you change the length and mass on it. That is why we do it. Thank you. Yum yum eat I'm, going on.

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Don't believe you.

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And then we used a very simple software.

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Now, some to line a model formula.

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But what wait, what what.

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It's called Monte Carlo Monte Carlo come on Musti.

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In bashing the computer compiled active or not era, mother.

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So, as you can see again, there's possibly a to aquifer system, there's this layer here with a low resistivity in another zone, so is so low resistivity of maybe 70 so.

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Not money tree about a minute, inaudible data, but a my boy. My aquifers are not a machine on guitar Nettie. Same y know the ya want to know yeah.

B

So see so we took this and then we just.

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Don't have that many body.

B

A

Our interpretation is.

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That there's a very high resistivity layer here the value is maybe 2,000 meters. We think it is a thank.

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You it's a tradition to our yeah, we'll go. Take a pointer, Katara, hey man turn on the town last. You know we're not the point like that: neon Jonathan, yellow box in Managua and.

B

The bedrock is from a box nearly 5 to 20 meters, Oh.

C

Mon Ami Danny, that's an antiqued enemy, not a--not, and.

B

Then below 20 meters, possibly there's a fractured aquifer with the lower value of 7000 meters, they're.

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Not retired fractured.

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Rock it could be 40 to 400 meters. Seventy not.

C

Whether resistivity narrow an alpinist, a mahogany, miss Amy, yo I had a resistive Network atomizer, another fracture 459 lat, where oh yeah do Buddakan our acquaintance. Talia taught me after George F cinema, Oh, No.

B

So for synthesis.

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A

B

Because we can look at the data from trek up in the 1g village, so.

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This is, this is Jacob wandering.

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Village, this is us in English.

C

Take a look at it. 0:01 see my locator how to belly up Ruti I, don't get it happen.

B

A

Made the comparison you can see.

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Maybe the purse have some similarities, but they're also quite.

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B

In terms of the values and the locations in.

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The document they may belly a viewer, an iguana.

B

C

B

At depth there is a lower resistivity ro.

C

Ma de la ma, parody or resistivity natives of power pan in a banana.

B

Over here, the lower sixth episode is about 9000 meters. Again, that's inside the range 40 to 400. So both these surveys show that there could exist fracture aquifer so.

C

Imagine at the urinal I'm at example, resistivity narrates only together any indeed gonna hit the road Briana Jeanne freshwater, tinnitus in agony, I, wanna.

B

Of course, actually find out.

B

Okay, that brings us to the end of the background section. So hopefully you have some more understanding of the physics geology.

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Business, never that would connect no yeah.