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.
Hi all,
I recently came across one of the proposed mechanisms by which black hole could be formed as stated above.Can someone please explain me what is it all about? Also what's their relationship with type IA supernovae? I always thought that, a black hole is formed only when a main sequence...
Faraday's law says that an induced voltage across a conductor is directly proportional to the rate of change of magnetic flux through the conductor, but I am having trouble getting my head round how it works in this situation.
Imagine a perfectly circular thin copper disc, and that this disc...
Hi there,
When you have a loop of wire and you move a bar magnet through it, you induce a current in the wire.
What if you were in a room where there was a magnetic field (not moving) that was stronger than the magnetic field produced by the magnet? If you moved the magnet through the loop...
Homework Statement
How would you prove that every graph G is an induced subgraph of an r-regular graph where r >= D (the largest degree of the vertices of G)?
Homework Equations
NA
The Attempt at a Solution
I can picture the answer for when G itself could be turned into a...
I have a question about calculating induced surface charge:
Consider a system composed of an infinite grounded conducting sheet located at z=0 and a point charge positioned some distance d above the sheet.
Via method of images, we can find the potential in the region z>0. When we are done, we...
Homework Statement
(Draw a diagram illustrating the direction of the electric current induced in a conductor as it passes through a magnetic field)
Write a short paragraph in which you explain your reasoning for the direction of the current in your diagram refer specifically to the motor...
Hi,
I am working on a case with a flexible cylinder with a flow of air inside and a cross flow of water. This is a fluid structure interaction case and the case is such that I can define the natural frequency of the air inside the cylinder and that would then be used to solve the structure...
There's no electric field inside a conductor, a classic observation of electrostatics. Any field that "should" exist is compensated for by charge redistribution on the surface of the conductor. This produces classic results like shielding since in a hollow conductive shell, the field is still...
Homework Statement
A square loop of side .45 m is placed in a region where there is a magnetic field of strength 8T directed perpendicularly out of the plane of the loop. If the magnetic field is increased to 14 T in .03 seconds, calculate the average emf induced in the loop
Homework...
Homework Statement
Hey everyone,
I'm studying for a final and have been having difficulty determining induced magnetic field and current direction. I have a document (link below) with 5 sample problems. I answered them all, and put my reasoning for the answers there in italics. Would...
Hi there,
If you have a stream of protons passing through the inside of a coil of wire (coils of wire at 45 degrees to current of protons) and say the current of protons induced a certain current in one of the loops, would the current induced in one loop be equal to the current in the entire...
Suppose now i have connected a solenoid with a dc power supply of 10V
When i increase the voltage to 20V the magnetic flux through the coil have increased
will emf be induced shortly to oppose the change?
what if i now change it to a 10V ac power supply
so will there always be induced emf...
Homework Statement
2 parallel long, straight conductors lie on a smooth plane surface. 2 other parallel conductors rest on them at right angles so as to form a square of side 'a' initially. A uniform magnetic field B exists at right angles to the plane containing the conductors. Now they start...
Hi, everyone:
Given a top space X, and a homeo. h: X--->X , we get an induced map
(by functoriality ) h_*: Pi_1(X)---> Pi_1(X) . We can also write
the map as a map g: Aut(X) --->Hom(Pi_1(X),Pi_1(X))
Is the map g always surjective.? . Almost definitely...
In a 1964 publication Bruno Rossi describes an experiment where cosmic rays could penetrate dense materials. Finding that cosmic radiation at sea level could penetrate over 1m of lead. In these same experiments he was also surprised to record a higher rate of detection, as many as 35 per hour as...
Homework Statement
Determine the emf induced in the square loop in the figure if the loop stays at rest and the current in the straight wire is given by I(t) = (15.0 A)sin(2500t) where t is in seconds. The distance a is 12.0 cm, and b is 15.0 cm.
Homework Equations
In the question...
If a time varying magnetic field of infinite dimensions crosses a plane at right angles what can we expect induced electric field lines to look like? Straight lines with direction determined by the right hand rule?
Hey guys, I have a scenario where I can't figure out what would happen.
If I have a magnetic sphere traveling down a track made of two conducting wires (each with current flowing through them)... what would happen?
I'm not sure how the magnetic field of the wire and the magnetic field of...
Homework Statement
A square coil (25 x 25 cm) that consists of 50 turns of wire rotates about a vertical axis at 1000 revolutions per minute. The horizontal component of the Earth's magnetic field at the location of the coils is 2 x 10-5. Calculate the maximum voltage induced in the coil by...
Homework Statement
[PLAIN]http://img220.imageshack.us/img220/2589/44045733.png
Semicircular wire MN of diameter L moves with speed v perpendicularly through a uniform magnetic field of strength B.
1. Find the magnitude of the induced emf generated between M and N.
2. State whether M...
Hi all Physics (masters)
I was reading a paper on the faraday's induction experiments; i didn't quite understood the reason why is current induced into a solenoid.
There is this solonoid and a Permanant magent is pushed inside the solonoid and we observe that a current flows (by a...
Sometimes when i swipe my card at walmart it doesn't read it , And the guy was like let's put it a plastic bag and then try it, and it works and I've heard a couple of other people doing this.
So when i slide my card the magnetic strip induces a voltage and reads the card. So why does...
Homework Statement
Describe with the aid of diagrams how the back emf and induced current vary in a single-coil DC motor over one full rotation of the armature.
Give particular attention to the rate of change of flux in the coil and to the direction(s) of the DC and induced current...
Homework Statement
A flat coil of wire consisting of 20 turns, each with an area of 50 cm2, is positioned perpendicularly to a uniform magnetic field that increases its magnitude at a constant rate from 2.0 T to 6.0 T in 2.0 s. If the coil has a total resistance of 0.40 Ω , what is the...
Hello everyone, i have a question about induced voltage that i need help answering, in my calculations i believe i have made a mistake about the total voltage induced in the coil. My calculations follow as: 390 RPM / 60 Seconds = 6.5 Hz x 6 pole pairs = 39 Hz x 6.28 = 244.92 radians per second...
Homework Statement
Using the method of images: discuss the problem of a point-charge “q” inside a hollow, grounded, conducting-sphere-shell of inner radius “a”. That charge "q" is located at {\left| {{{{\bf{\vec r}}}_0}} \right|}. We don't care about its angular position. Oh yes: the problem...
Hi everyone,
I'm working on COMSOL's ac-dc module and I'm trying to find the magnetic field which is created by an electrode pair (dipole). The working environment of the pair has nonzero conductivity and relative permittivity.
I first found the current density between the electrodes in...
Homework Statement
A bar of 1 m length aligned in y direction moves in +x direction at 10 m/s, in space where B = 1 T pointing in the -z direction. Calculate the motional EMF.
If the bar above, is a part of a circuit with a light bulb of 10 ohms resistance, what would be the induced current...
I'm a bit confused about magnetism and electromagnetic induction.
On the one hand I understand that to induce a current we need a change in magnetic flux.
On the other... a charge moving relative to an external magnetic field experiences a force. If the field is uniform then we would...
(EDIT fixed format)
Hi,
I have a question about properties which are common to a manifold and its submanifolds. I start with the metric.
M \subset N, dim(M) = m, dim (N) = m+1
let g^N be the metric of N, so that (N,g^N) is a riemanian manifold and N is a submanifold.
Now, I'm...
There is well known pyroelectric effect in which polarisation of
crystals occur under heat.
I thought that pyroelectric could be good energy converter if not
problems associated with it.Thus,heat should be applied in impulses and there might be a great looses associated with cycles.Also...
According to Nash theorem http://en.wikipedia.org/wiki/Nash_embedding_theorem" every Riemannian manifold can be isometrically embedded
into some Euclidean space. I wonder if it's true also
in case of pseudoremanninan manifolds. In particular is it possible to find
a submanifold in...
Can anyone point me to a good site that explains current induction, specifically when a coil is placed around an energized, current carrying conductor? I would like to understand this principle to understand how power can measured in 3 phase power systems by using coils as a measuring element.
Hi, hopefully this is the right board to ask this on.
I'm currently reading Groups, representations and Physics by Jones, and trying to get my head around induced transformations of the wavefunction. The problem is I seem to understand nearly all of what he's saying except the crucial part I...
my question is why oxygen lines does not appear in metal oxides spectrum taken at 532nm wavelength of Nd:YAG laser at atmospheric pressure. and what is the criteria for selecting emission lines for analysis?
Homework Statement
C
alculate the emf (in volts) induced in a loop of wire if the magnetic flux in the loop increases from zero to 71.1 milliweber in 16.7 millisec.
Homework Equations
faradays Law
The Attempt at a Solution
The only law I know is faradays law which uses Area...
Homework Statement
"You have an ideal solenoid with n windings per meter, with a current I = I' sin(wt) going through it. Calculate the induced electric field inside and outside the coil. Side: compare with dipole antenna."
Homework Equations
Maxwell equations
B = n mu I (magnetic...
I dabble in miniature milling/machining with my home CNC setup. I'm building a low temperature engine and have a question. The piston will be a neodymium magnet(s) set in graphite. Rather than using mechanical linkages and a crankshaft I want to use magnets to control the length of throw. By...
A recent explanation for "the majority of ball lightning observations":
Is this plausible?
A way to debunk this would be to find credible ball lightning videos(maybe on youtube), but i don't know if there are any.
A square loop of wire of side a is rotating with frequency \omega in a magnetic field. I understand that at time t, a magnetic field B=B_{0}sin\omega t passes through the loop. But why does the current induced in the loop vary twice with the frequency of rotation? What is the expression of...
I am trying to understand Lenz law as it applies to an A.C. generator, Lenz law says " an induced current is always in such a direction as to oppose the motion or change causing it". Does this mean that if the north pole of a magnet passes a conductor in a stator, that the current induced in the...
Homework Statement
A flat coil of wire consisting of 20 turns, each with an area of 50 cm^2 is positioned so that the normal to its plane is at the angle of 30 degrees to a uniform magnetic field that increases its magnitude at a constant rate from 2.0T to 8.0T in 2.0 s.
Homework Equations...
Homework Statement
A 25-turn circular loop of wire has a diameter of 1m. In 0.2 seconds it is flipped 180 degrees at a location where the magnitude of the Earth's magnetic field is 50 micro T. What is the emf generated in the loop?Homework Equations
-(dB/dt)(A)=VThe Attempt at a Solution
When I...
Rotating Conducting Cylinder in B -- Induced Voltage
[PLAIN]http://img690.imageshack.us/img690/2600/47007002.jpg
I understand how to use motional emf to solve this problem.
\int_C U \times B\, dl
U = \omega R
and
\int_C dl = H
so the answer, symbolically, is
\omega RHB
where \omega is the...
Homework Statement
A metal loop is attached to an axle with a handle as shown. The north pole of a magnet is placed below the loop and the handle turned so that the loop rotates counterclockwise at a constant angular speed.
On the two diagrams below, indicate the direction of the induced...
1. A 100-turn, 2.0-cm-diameter coil is at rest in a horizontal plane. A uniform magnetic field 60 degrees away from vertical increases from 0.50 T to 1.50 T in 0.60 s.
2. EMF = N*d(phi)/dt
phi = flux = ABcos(theta)
3. dB/dt = 1/0.6
EMF = 1000*(1/0.6)*pi*r2*0.5 = 0.262 V
Is...
Homework Statement
The magnetic field inside a 5.0-cm-diameter solenoid is 2.0 T and decreasing at 4.90 T/s
What is the electric field strength inside the solenoid at point on the axis?Homework Equations
E=(r/2)*(dB/dt)The Attempt at a Solution
E=(.025/2)*(4.9)= 0.06125 V/m
Not sure what's...
A magnetic field B, that is decreasing with time is directed out of the page and passes through a loop of wire in the plane of the page, as in my drawing (ignore that the dots are not evenly spaced, you can only do so much in paint) Which of the following is true of the induced current in the...
Homework Statement
A very thin conducting disc of radius a and conductivity \sigma lies in the x-y plane with the origin at its center. A spatially uniform induction is present and given by B=B_0 cos\(\omega t \)\hat{z}. Find the induced current density \vec{J} in the disc.
Homework...
If anyone can advise that would be great.
1. The plane of a 5 turn coil of 5mm² cross sectional area is rotating a 1200 r.p.m in a magnetic field of 10mT.
Q. Calculate the amplitude of the induced voltage across the coil
Data:
5 turns
c = 1200 rpm
A = 5cm²
B = 10 mT
2. φ =...