What is Induced: Definition and 971 Discussions

Induced seismicity refers to typically minor earthquakes and tremors that are caused by human activity that alters the stresses and strains on the Earth's crust. Most induced seismicity is of a low magnitude. A few sites regularly have larger quakes, such as The Geysers geothermal plant in California which averaged two M4 events and 15 M3 events every year from 2004 to 2009. The Human-Induced Earthquake Database (HiQuake) documents all reported cases of induced seismicity proposed on scientific grounds and is the most complete compilation of its kind.Results of ongoing multi-year research on induced earthquakes by the United States Geological Survey (USGS) published in 2015 suggested that most of the significant earthquakes in Oklahoma, such as the 1952 magnitude 5.7 El Reno earthquake may have been induced by deep injection of waste water by the oil industry. A huge number of seismic events in fracking states like Oklahoma caused by increasing the volume of injection. "Earthquake rates have recently increased markedly in multiple areas of the Central and Eastern United States (CEUS), especially since 2010, and scientific studies have linked the majority of this increased activity to wastewater injection in deep disposal wells."Induced seismicity can also be caused by the injection of carbon dioxide as the storage step of carbon capture and storage, which aims to sequester carbon dioxide captured from fossil fuel production or other sources in Earth's crust as a means of climate change mitigation. This effect has been observed in Oklahoma and Saskatchewan. Though safe practices and existing technologies can be utilized to reduce the risk of induced seismicity due to injection of carbon dioxide, the risk is still significant if the storage is large in scale. The consequences of the induced seismicity could disrupt preexisting faults in the Earth's crust as well as compromise the seal integrity of the storage locations.The seismic hazard from induced seismicity can be assessed using similar techniques as for natural seismicity, although accounting for non-stationary seismicity. It appears that earthquake shaking from induced earthquakes is similar to that observed in natural tectonic earthquakes, although differences in the depth of the rupture need to be taken into account. This means that ground-motion models derived from recordings of natural earthquakes, which are often more numerous in strong-motion databases than data from induced earthquakes, can be used. Subsequently, a risk assessment can be performed, taking account of the seismic hazard and the vulnerability of the exposed elements at risk (e.g. local population and the building stock). Finally, the risk can, theoretically at least, be mitigated, either through modifications to the hazard or a reduction to the exposure or the vulnerability.

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  1. T

    Rate of Field Change for Induced Current of Loop

    Homework Statement A single conducting loop of wire has an area of 8.0×10−2 m^2 and a resistance of 110 Ω. Perpendicular to the plane of the loop is a magnetic field of strength 0.37 T. At what rate (in T/s) must this field change if the induced current in the loop is to be 0.33 A...
  2. T

    What is the relationship between induced emfs and circuit shape in a solenoid?

    So if a circuit goes once around an extremely long solenoid whose changing current causes an induced emf of 360 V (in the circuit) at a particular time, does that mean that regardless of the shape of the circuit, the induced emf will be 1 V per degree? If the circuit has only one resistor whose...
  3. W

    Strength of induced magnetic field inside an inductor

    I am trying to make a crude coil gun. I remember that if I run current through a coil of wire, it generates a magnetic field according to the right hand rule. Will the inductance of the coil of wire greatly affect the strength of the magnetic field, or is it mainly due to the strength of the...
  4. K

    Pointwise Convergence For Induced Distributions

    Homework Statement If U \subseteq \mathbb R^n find a sequence of locally integrable functions f_n \in L^1_{\text{loc}}(U) which converge pointwise, but whose induced distributions \langle f_n, \cdot \rangle: C_c^\infty(U) \to \mathbb R, \qquad \langle f_n, \phi \rangle = \int_U f_n \phi...
  5. DocZaius

    Induced EMF through variable-resistance-wire due to Faraday's Law

    Hello, While considering Faraday's Law of Induction, I tried to think of a situation which would expose some difficulties I have with the notion that there is an induced EMF without clear regions of relatively high and low voltage (as in a battery). Here is what I thought would get me started...
  6. phosgene

    Determine the direction of induced current in a wire

    Homework Statement A wire carrying a current experiences a force when it is placed in a magnetic field. This phenomenon forms the basis of many devices including the electric motor and the gavlvanometer. The diagram shows a uniform magnetic field B with magnitude 25mT directed towards the...
  7. O

    Force induced by mass (very simple

    Homework Statement I'm supposed to draw a FBD with labeled forces of the footpedal and the actual kicking thingy (2 separate system) http://img842.imageshack.us/img842/3812/capture2bf.png Homework Equations No equations really The Attempt at a Solution Well I got all of em right but...
  8. R

    Back EMF: Explaining the Counter Voltage Induced by Change in Current

    Hi, I have a question about back emf So, my understanding of back emf (\epsilon_b=-L\frac{dI}{dt})is that its the counter voltage that's induced by change in current, whether it be from a battery or magnetic field (\epsilon_0). We can model this as an LR circuit where \epsilon_0 +\epsilon_b=IR...
  9. S

    Average Torque on an Induced Current Loop

    Homework Statement A rectanglar loop of wire encloses an area A, has a resistance R and a self-inductance L. The loop is suspended from the mid point of one of its sides and placed in a horizontal oscillating magnetic field B = B0 sin ωt such that the field makes an angle θ with the normal to...
  10. M

    Induced EMF through a coil How/Why?

    Homework Statement In a lab I passed a magnet through a coil and measured the voltage. I need/want to know why when moving a magnet through a coil you induce a current. I don't necessarily need a direct answer - I more just want to know if my argument holds and where to look if I'm...
  11. jegues

    Do Induced EMF Direction and Voltage Signs Contradict?

    Homework Statement Are these two things not contradicting? Homework Equations The Attempt at a Solution See figure attached. Aren't these contradicting one another? They need a negative sign in there, correct?
  12. T

    Determining direction of induced current

    How do you determine that direction of the AC current at a given instant in this model. Does it really matter? The red arrows change direction when the coil is horizontal. Does anyone know why the current changes direction at that point? Why does it switch direction at the horizontal and not the...
  13. jegues

    Direction of Induced EMF (Faradays Law) Confusion

    Homework Statement See figure attached. Homework Equations The Attempt at a Solution If we attempt to solve part a) in this question we encounter several confusions. If we assume i(t) to be a positive current, the magnetic flux will flow through the core in a counter...
  14. jegues

    Induced EMF Moving Current Loop

    Homework Statement See figure attached. Homework Equations The Attempt at a Solution I'm having some confusion about the negative sign within this problem. If you compute the curl of the expression shown in the figure you'll find that it's equal to, -10v_{0} \hat{k} But...
  15. W

    How does induced charge separation work and why can it be confusing?

    Homework Statement I am having trouble understanding the concept of induced charge separation. In my textbook, there is a diagram that demonstrates the procedure, but it gets confusing because the first image is normal, and then it gets inverted? I don't understand in the second set-up if it...
  16. N

    Confused about voltage induced across inductors

    Confused about voltage induced across inductors :( Hi, As you may have gathered from the topic title, I'm rather confused about inductors :rolleyes: I have another topic going regarding boost converter design, which involves an inductor, but as this confusion/question/observation is really...
  17. C

    What causes induced magnetic fields?

    ok so you have a current flowing through a wire that induces a magnetic field, the direction of which is given by the right hand rule. my question is: WHY is there an induced magnetic field? what actually causes it? thanks. (fyi I am in classical e&m right now)
  18. A

    Repeat Q: Ignore. Show what the magnitude of induced emf

    Show what the magnitude of induced emf Homework Statement Consider a magnetic field B = K(x3z2,0, -x2z3)sinωt in the region of interest, where K and ω are positive constants and t is variable time. Show that the magnitude of the induced emf around a circle R in the plane z = a with its center...
  19. A

    Show what the magnitude of induced emf

    Someone who knows what they are talking about: Show what the magnitude of induced emf Homework Statement Consider a magnetic field B = K(x3z2,0, -x2z3)sinωt in the region of interest, where K and ω are positive constants and t is variable time. Show that the magnitude of the induced emf...
  20. D

    Induced Magnetic Field in a Non-Uniform Electric Field

    Homework Statement An electric field is directed out of the page within a circular region of radius R = 3.00 cm. The field magnitude is E = (0.500 V/ms)(1 - \frac{r}{R})t, where t is in seconds and r is the radial distance (r≤R). What is the magnitude of the induced magnetic field at a...
  21. G

    Induced emf with no change in flux

    If a loop is moved in a uniform magnetic field such that the direction of its motion is perpendicular to the magnetic field, then no change of flux occurs. Then according to faraday, no emf is induced... But I was thinking that can the emf be produced in it due to the deflection force?
  22. E

    Induced motional emf conceptual question

    A magnetic field points into the page. A conductive bar is moved to the right (perpendicular to the magnetic field). Why do the electrons move downwards toward the bottom of the bar? The book doesn't offer a good explanation of this... using right hand rule I would say that the electrons are...
  23. S

    Airfoil Induced Drag Energy Conservation

    Consider the production of lift only as the reaction force from displacing a mass of air downwards. No matter the mathematical abstraction (Bernoulli, circulation theory) this Newtonian explanation must hold true. So now imagine a rectangular wing in a wind tunnel where the wing spans the...
  24. W

    Induced current in conductor moving circularly in constant B-field

    Homework Statement A light bulb with resistance R is attached on a metal rod which is rotating around the point O on the figure. The metal rod is in contact with an electrical conductor which is a part of a circle with radius d. The metal rod and the circular electrical conductor is a closed...
  25. B

    Understanding Induced EMF: Basic Concepts and Doubts

    Basic question on induced emf - ATTACHMENT CORRECTED PLEASE RE-READ Hi Please read the attached doc which is excerpted from the text University Physics by Young & Freedman.The discussion is on the emf induced in a loop made of a superconducting material when a magnet is moved towards it...
  26. T

    Emf induced on an eccentric rotating bar

    Suppose that a conducting bar is rotating with a speed ω, around an axis a distance a from one end, and b from the other. Suppose further that it is immersed in a uniform magnetic field B parallel to the axis of rotation, and that the measured difference of potential between both ends is V. I...
  27. I

    Induced current in a loop circuit magnetic field

    Homework Statement Homework Equations I know this is supposed to use Lenz's law, but I don't really understand it V=IR The Attempt at a Solution I calculated the resistance of the circuit to be 6.4e-6 / .0015 = 0.00426666667, but that's as far as i know what to do
  28. P

    Induced Solenoid Voltage by external magnetic fields

    Homework Statement In my physics lab, we were asked to connect an unpowered solenoid to an oscilloscope and then move a magnet through the solenoid and observe the changes in voltage on the oscilloscope. First we were asked to move the north pole of the magnet into the solenoid and then the...
  29. Y

    Equivalent circuit of induced EMF of coil.

    I want to model a coil circuit with induced EMF. I want to verify that my model is correct in a circuit. That the voltage developed across the load is calculated correctly. From the equivalent circuit, you can see the current depend on the jX_L and it acts as a low pass filter in the complete...
  30. D

    Induced magnetic field in rings

    Hello, Say I have two concentric conducting rings, where r1 >> r2 (why is this important, btw?), and I run a time alternating current I(1) thru the larger one. This will create a magnetic field B (also) thru the smaller ring, which in turn will create itself a magnetic field B2 and so on...
  31. Y

    Voltage induced into coax by external electric field.

    I want to verify the mechanism to which a varying E can induce voltage into a shielded coax. According to Maxwell \nabla \times \vec E = -\frac{\partial \vec B}{\partial t} \;\hbox { and }\; \nabla \cdot \vec E = \frac{\rho_{free}}{\epsilon} From this, with varying E, you induce...
  32. K

    Definition of induced representation

    http://planetmath.org/encyclopedia/InducedRepresentation.html The thing I don't get is the definition of a group element g's action on a vector \sigma v. In the link it defines the action as g(\sigma v):=\tau (hv), where \tau is the unique left coset of G/H containing gg_{\sigma}(i.e. such...
  33. C

    Lenz' Law, induced current in a ring falling

    Homework Statement A ring falls through a horseshoe magnet. Before reaching the magnet, is the current induced in the ring clockwise or counterclockwise? What about after the ring has passed through the magnet? The answers are clockwise before the ring passes through, and...
  34. C

    Estimate induced emf in the coil

    [Solved] Estimate induced emf in the coil Homework Statement Consider a single-loop coil whose magnetic flux is given by this image: Estimate the induced emf in the coil at times near t = 0.3s, t = 0.4s and t = 0.5s This is for algebra-based physics. Homework Equations emf = -N*(change in...
  35. O

    Schroedinger's Equation for Electromagnetic field induced by charged wire

    Greetings all! I'm completely new to Quantum Mechanics (my PhD research is in Computer Vision) and I am planning to apply some concepts to my research. I would like to know whether it's possible to get the Wave Equation over the components of a \mathbf{B}=(B_\phi,B_r,B_z) field induced by...
  36. K

    Induced voltages in cables in trunking

    I was carrying out a insulation resistance test on a ring main circuit at the dist board in an industrial workshop. The majority of the wiring is single core pvc cables run in metallic trunking and conduit. The majority of circuits have no cpc as the trunking/conduit is being used. When I...
  37. B

    Q Value for spontaneous fission and neutron induced fission

    Homework Statement What is the Q value in units of MeV in each of the following processes? i) The spontaneous fission of 232U92 to 145La57 and 87Br35 ii) The neutron induced fission of 232U92 to 146La57 and 87Br35 Explain why heavy nuclei such as 232U92 do not usually undergo fission...
  38. L

    Induced charges and electrostatic potential

    There is one point I am unclear upon in terms of indued charges. If a charge is induced by another charge, will the potential from the induced charge have an effect on the inducing charge. It seems that if it were the case you would be getting (increasing) energy from nothing, however if it...
  39. B

    What Maps Induce Isomorphisms on Lower but Not Higher Homology Groups?

    Hi, All: I am curious to find examples of maps f:X-->X ; X an n-dimensional manifold that induce isomorphisms on , say, the first k<n homology groups, but not so on the remaining n-k groups. I can see if we had maps g:X-->Y, we could start with Y=X, let f be an automorphism...
  40. B

    Calculating Kg Force for Generating 1 Watt of EMF in Magnetic Generators

    Hi, I wonder if someone can help me. Looking at magnetic generators, we spin the magnets around which will induce an EMF. This EMF will create a magnetic field opposite that of the magnets, thereby creating a drag. If I had to generate 1 watt for 1 second, how much kg force will I need to...
  41. H

    Current Induced in Loops by Resistance Change

    Homework Statement a). If the resistance of the resistor in Fig. 21-46 is slowly increased, what is the direction of the current induced in the small circular loop inside the larger loop? b). What would it be if the small loop were placed outside the larger one, to the left? Homework...
  42. L

    Effect of current induced by rod magnet

    If you had a lined retangular section solenoid inclined at a angle of 45 deg and you rolled a rod magnet ( just fits inside the retagular section) down it. Would the current induced in the solenoid brake or accelerate the rod magnet.
  43. R

    Cosmic rays and induced radioactivity

    Homework Statement 90% of the cosmic rays that fall on Earth are protons. So the outside of the Earth is hit by a net positive charge but does not seem to be, in particular, positively charged. How do you explain this? One last thing: I read that a body that is exposed to radiation becomes...
  44. S

    Understanding Induced Eddy Currents & Magnetic Retarding Force FB

    I came across this in my reading and I don't understand: How does the induced eddy current produce a magnetic retarding force FB, and how do we know the direction of FB? Thanks!
  45. J

    Emf induced in a ring rolling in non-uniform magnetic field

    I have got a doubt regarding the situation when a ring rolls in a non-uniform magnetic field. We can see that the flux linkage is increasing (considering dB/dt to be positive). So EMF should be induced in the loop. But if we join any two points, say the instantaneous axis of rotation and the...
  46. M

    Does the direction of winding affect the induced emf in a an inductor coil?

    Hi, What if the inductor coil is wound one way rather than the other. Then the circular flow of current will be clockwise in one case and anticlockwise in the other. And if the inductor is connected to an ac source, then the current will vary. Now in both the orientations, the variation...
  47. B

    Find EMF Induced When Converting 2-Turn Coil to 1-Turn

    How would one go about finding the EMF induced when a two-turn coil of wire is straightened into a one-turn coil?
  48. D

    How Is Average Induced Voltage Calculated in a Rotated Coil?

    Homework Statement A coil with 10 windings(radius 0,07m) is inside a homogenous magnetic(B=0,050T) field, it makes an angle of 90 degrees with the field lines so the magnetic flux is at it's max. Over a period of 0,050 seconds it gets turned by 180 degrees, what is the average induced...
  49. F

    Induced emf as a magnet passes through a solenoid

    I'm doing a lab write-up for physics 2. The experiment is about the title, a bar magnet being dropped through a solenoid. I have to explain four graphs that plot the change in emf (y axis) vs. time (x) axis. There are incoming and outgoing peaks on these graphs. I have to tie these results...
  50. F

    Induced Emf: Magnet Passes through a Coil

    I'm doing a lab write-up for physics 2. The experiment is about the title, a bar magnet being dropped through a solenoid. I have to explain four graphs that plot the change in emf (y axis) vs. time (x) axis. There are incoming and outgoing peaks on these graphs. I have to tie these results...
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