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Author Topic:   Heat release from tectonic friction
PaulK
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Posts: 12688
Joined: 01-10-2003
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Message 16 of 102 (683375)
12-10-2012 2:02 AM
Reply to: Message 15 by Faith
12-10-2012 1:43 AM


Re: Earthquakes
If you were being scientific you'd already have done basic checks like this.

But OK, your model seems to assume a linear decline.

Therefore 2000 years ago the rate would be 4/9 of the maximum, about 21,120 inches per year.

By herebedragons calculation that gives us a rate about 14,000 times greater than for the San Andreas fault.

I think we can be sure that earthquake frequency was not so great only 2,000 years ago, so a model based on a linear decline must be rejected in favour of one that uses a much faster rate of decrease, and consequently a much higher starting rate.


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 Message 15 by Faith, posted 12-10-2012 1:43 AM Faith has responded

Replies to this message:
 Message 17 by Faith, posted 12-10-2012 2:05 AM PaulK has responded

    
Faith
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Posts: 24846
From: Nevada, USA
Joined: 10-06-2001
Member Rating: 1.1


Message 17 of 102 (683376)
12-10-2012 2:05 AM
Reply to: Message 16 by PaulK
12-10-2012 2:02 AM


Re: Earthquakes
Sorry I have no way of imagining what that rate of earthquakes means in real life so you are going to have to spell it out with more detail, with a little graphic imagination perhaps, as well as something clearer about the model you think works better with higher starting rate and faster decline. Why suppose a high number of earthquakes rather than a smaller number of huge ones?

Edited by Faith, : No reason given.


He who surrenders the first page of his Bible surrenders all. --John William Burgon, Inspiration and Interpretation, Sermon II.

This message is a reply to:
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PaulK
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Posts: 12688
Joined: 01-10-2003
Member Rating: 2.8


(1)
Message 18 of 102 (683378)
12-10-2012 2:22 AM
Reply to: Message 17 by Faith
12-10-2012 2:05 AM


Re: Earthquakes
Herebdragons numbers would give 36 magnitude 6 quakes PER DAY on a fault the length of the San Andreas. I think that we can say that even one per day per fault would be extremely implausible.

Here's a description of a magnitude 6+ quake:


Can be damaging/destructive in populated areas in regions of any size. Damage to many to all buildings; poorly designed structures incur moderate to severe damage. Earthquake-resistant structures survive with slight to moderate damage. Most likely felt in wider areas; likely to be hundreds of miles/kilometers from the epicenter. Can be damaging of any level further from the epicenter. Strong to violent shaking in epicentral area. Death toll between none and 25,000.

It's not the sort of thing that goes unnoticed.


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 Message 17 by Faith, posted 12-10-2012 2:05 AM Faith has responded

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Faith
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Posts: 24846
From: Nevada, USA
Joined: 10-06-2001
Member Rating: 1.1


Message 19 of 102 (683381)
12-10-2012 2:37 AM
Reply to: Message 18 by PaulK
12-10-2012 2:22 AM


Re: Earthquakes
OK I will ponder and pray about it.

Now how about the heat factor?


He who surrenders the first page of his Bible surrenders all. --John William Burgon, Inspiration and Interpretation, Sermon II.

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 Message 18 by PaulK, posted 12-10-2012 2:22 AM PaulK has responded

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 Message 21 by Coragyps, posted 12-10-2012 8:45 AM Faith has not yet responded
 Message 23 by herebedragons, posted 12-10-2012 10:35 AM Faith has responded

    
PaulK
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Posts: 12688
Joined: 01-10-2003
Member Rating: 2.8


(2)
Message 20 of 102 (683392)
12-10-2012 7:58 AM
Reply to: Message 19 by Faith
12-10-2012 2:37 AM


Re: Earthquakes
I don't know about the heat, although I'd say that the friction in the OP is distinct from the heat of the magma.

(And then if you want accelerated radioactive decay in that period, there's heat from that, and probably the Siberian and Deccan Traps would be pretty hot, too...)


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Coragyps
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Posts: 5268
From: Snyder, Texas, USA
Joined: 11-12-2002


(3)
Message 21 of 102 (683395)
12-10-2012 8:45 AM
Reply to: Message 19 by Faith
12-10-2012 2:37 AM


Re: Earthquakes
OK I will ponder and pray about it.

I'm sure that will work as well as calculating something, or looking at the historical/archaeological record of earthquakes.

Probably better.

Edited by Coragyps, : fix tag


"The Christian church, in its attitude toward science, shows the mind of a more or less enlightened man of the Thirteenth Century. It no longer believes that the earth is flat, but it is still convinced that prayer can cure after medicine fails." H L Mencken

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herebedragons
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Posts: 1324
From: Michigan
Joined: 11-22-2009
Member Rating: 6.0


(2)
Message 22 of 102 (683398)
12-10-2012 8:51 AM
Reply to: Message 20 by PaulK
12-10-2012 7:58 AM


Re: Earthquakes
I don't know about the heat, although I'd say that the friction in the OP is distinct from the heat of the magma.

I don't think that heat from friction would have played a significant role in raising the temperature of the hydrosphere (see Message 10). I thought I would try to estimate the heat input from magma later today and see what that comes out to.

And then if you want accelerated radioactive decay in that period, there's heat from that

Actually that is one of the points that need to be brought up in calculations based on this model. The continental plates move by convection currents that are caused by heat differential in the interior of the earth. This heat is generated primarily by radioactive decay. YEC proposal of accelerated decay could explain the increased heat needed for the increased convection current rates needed to move the plates faster. However, I don't think there could be enough heat differential to account for 20,000 times the rate of convection. The crust may have been thinner and the molten portion of the mantle extend further into the upper crust, which would have allowed for better transfer of motion from mantle to plates.

So possibly that could account for some increase in the rates of plate movement - what if it was 100 times faster and account for increased radioactive decay. But that comes no where near the rate it needs to be to move the Americas 3000 miles away from Africa in 4300 years.

You know if YEC models proposed a earth that was "young" as in around 100 million years old, they may be have some credibility in their models. But try to cram all of earth's history in to 6,000 years ... it is just untenable. The problems are off by orders of magnitude, not just a little bit here and there.

HBD


Whoever calls me ignorant shares my own opinion. Sorrowfully and tacitly I recognize my ignorance, when I consider how much I lack of what my mind in its craving for knowledge is sighing for. But until the end of the present exile has come and terminated this our imperfection by which "we know in part," I console myself with the consideration that this belongs to our common nature. - Francesco Petrarca

"Nothing is easier than to persuade people who want to be persuaded and already believe." - another Petrarca gem.


This message is a reply to:
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herebedragons
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Posts: 1324
From: Michigan
Joined: 11-22-2009
Member Rating: 6.0


(2)
Message 23 of 102 (683406)
12-10-2012 10:35 AM
Reply to: Message 19 by Faith
12-10-2012 2:37 AM


Re: Earthquakes
OK I will ponder and pray about it.

Faith, you seem like such a nice person and I do admire your faith. I don't want to hurt that in any way, but I don't think that having faith means denying reality. I too am a person of faith and believe fully in what is acclaimed by the Apostles Creed. But I have completely abandoned the idea that the earth is very, very young (ie. 6,000 years). To believe that forces me to deny reality. A young earth is not one of the pillars of my faith.

So all I ask of you is that you do look at things with an open mind and realize that God gave us both the Bible AND reality. The two don't have to be mutually exclusive. (I know you will say the bible IS reality, but what I mean by reality is what we can observe by studying the creation).

Now how about the heat factor?

I gave some estimates of the heat generated from friction in Message 10. I was really surprised at how little affect that amount of energy released would have on the ocean temperatures. I will try to come up with the amount of heat from lava flows later today. But honestly, I don't think it will be a huge factor either - the hydrosphere is just too immense and can absorb enormous amounts of energy.

Also check out Message 22 for some additional problems with this model.

Another point of reality is that there is just no way there was this amount of tectonic activity as recently as 2000 B.C.E. There are just too many know civilizations that date from that time that did have large cities and population centers in major fault areas - in particular the Arabian plate and Indian plate. This would have affected Egypt, Mesopotamia, Greece and India - all with civilizations older than 2000 B.C.E.

So now we need to cram most of the plate movement into a couple hundred years immediately after the flood. You would be better off assuming that the continents were created close to their present positions. Why does a YEC model need to have land masses gathered into one place to begin with?

So even if the heat factor is greatly exaggerated, it doesn't make the model anymore tenable.

HBD


Whoever calls me ignorant shares my own opinion. Sorrowfully and tacitly I recognize my ignorance, when I consider how much I lack of what my mind in its craving for knowledge is sighing for. But until the end of the present exile has come and terminated this our imperfection by which "we know in part," I console myself with the consideration that this belongs to our common nature. - Francesco Petrarca

"Nothing is easier than to persuade people who want to be persuaded and already believe." - another Petrarca gem.


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 Message 19 by Faith, posted 12-10-2012 2:37 AM Faith has responded

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herebedragons
Member
Posts: 1324
From: Michigan
Joined: 11-22-2009
Member Rating: 6.0


(1)
Message 24 of 102 (683454)
12-10-2012 5:54 PM
Reply to: Message 3 by Trixie
12-08-2012 11:33 AM


Calculations regarding the heat produced by lava flow at divergent plates under water.

Figure half of the estimated 40,000 miles of faults are divergent plate boundaries. That would 20,000 miles of lava per day 10 feet wide and I will figure 10 feet deep that can transfer heat to the surface. That works out to 1.06 x 10^10 cu. Ft. of lava per day forced into the ocean. Convert to cm^3 and you get 3.00 x 10^14 cm^3.

Use a density of 2.5 g / cm^3 (granite is 2.6 - 2.8) and you have 7.50 x 10^11 kg of lava per hour.

Lava initial temp = 1000 deg C
Lava final temp = 100 deg C
Change in temp = 900 deg C
Specific heat of lava = 1046.5 J / kg C (would be different for the solid and liquid state but we'll just use the same value for simplicity)
Specific heat * change in temp = 9.42 x 10^5 J / kg

Latent heat of fusion for lava = 418,600 J / kg

Total heat per kg = 1.36 x 10^6 J / kg

Total heat per hour = 7.50 x 10^11 kg * 1.36 x 10^6 J / kg = 1.02 x 10^18 J

Using the energy required to raise the temperature of the hydrosphere by 1 deg C of (5.6 x 10^24 J / deg C) ...

Total temp increase per hour would be (1.02 x 10^18 J) / (5.6 x 10^24 J / deg C) = 1.82 x 10^(-7) deg C per hour

Over 4300 years temperature change would be about 7.0 deg C

While 7 deg C doesn't sound like a whole lot, it would be a significant, possibly catastrophic, change in ocean temperatures. In the discussions about global warming, scientists are concerned that ocean temperatures are raising 1 or 2 deg C. However, I don't see it boiling off the oceans.

I can't guarantee these calculations are correct, and instinctively they seem rather low. Maybe someone can offer some suggestions to make these estimates more accurate????

HBD

Data Source


Whoever calls me ignorant shares my own opinion. Sorrowfully and tacitly I recognize my ignorance, when I consider how much I lack of what my mind in its craving for knowledge is sighing for. But until the end of the present exile has come and terminated this our imperfection by which "we know in part," I console myself with the consideration that this belongs to our common nature. - Francesco Petrarca

"Nothing is easier than to persuade people who want to be persuaded and already believe." - another Petrarca gem.


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 Message 3 by Trixie, posted 12-08-2012 11:33 AM Trixie has not yet responded

  
TrueCreation
Inactive Member


(2)
Message 25 of 102 (684019)
12-15-2012 2:24 AM


Back of envelope calculation
Frictional heat dissipation isn't necessarily a problem for heat budget problems because once you initiate melting slip efficiency will increase. You could look at this in detail using realistic rheologies (flow laws for rocks under stress) with all sorts of dependencies which theoretical geophysicists like myself are very interested in, but this doesn't really matter in our case.

Heat is, to me, probably the most obvious problem inherent to any young earth hypothesis. The heat problem is (at least) two-fold: (a) radiogenic heat (most heat producing radioisotopes are concentrated in continental crust) and (b) the conductive cooling of oceanic lithosphere.

I'm on vacation now so I'll just do a quick calculation focusing on the latter problem, which happens to be close to my research specialty. The thermal structure of oceanic lithosphere is, to first order, extremely well understood. The main idea is that we know that oceanic lithosphere is formed at spreading centers, migrates away and cools. Observable consequences of cooling are things like surface topography, surface heat flow, potential fields (gravity, geoid), and tomographic methods (mostly in seismology), so models can be well constrained. A very rough approximation of the heat content removed from exposed oceanic lithosphere is about 9*10^28 Joules, which comes from cooling the upper 100 km of the mantle below oceans (~3*10^19 m^3) by about 700 K with a volume heat capacity of about 4*10^6 J m^-3 K^-1. This is close to a quick integration of seafloor heat flow for a detailed lithospheric cooling model I have developed. I get about 8.4*10^28 J.

We can probably consider this a lower bound since you will have to account for a far more than currently exposed seafloor given the record of tectonic motion and subduction, anyway.

This amount of heat is enough to heat the oceans by about 14300 K (mass=1.4*10^21 kg, specific heat=4200 J/kg/K), or boil an ocean 140 times more massive than Earth's.

If you want to release heat over the course of a year, the average surface heat flux over that time would have to be about 3*10^8 terrawatts. Released over 1000 years the surface heat flux is about 3*10^5 TW. This can be compared to the present day seafloor heat flux of about 30 TW or the solar heat flux of about 1.7*10^5 TW.

I hope I haven't made any mistakes.


Replies to this message:
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 Message 27 by NoNukes, posted 12-15-2012 11:34 AM TrueCreation has responded

  
herebedragons
Member
Posts: 1324
From: Michigan
Joined: 11-22-2009
Member Rating: 6.0


(1)
Message 26 of 102 (684050)
12-15-2012 8:55 AM
Reply to: Message 25 by TrueCreation
12-15-2012 2:24 AM


Re: Back of envelope calculation
This amount of heat is enough to heat the oceans by about 14300 K

Which is much more like the numbers I expected to get when I did some rough calculations. But I came up with much, much less.

It seems the main difference in our numbers is that you accounted for cooling of the entire seafloor 100km deep. I assumed that the majority of the seabed would have been cooled prior to the flood, maybe it was created cooled off? So the only new input that needed to be cooled was the lava that filled the gap created when the plates diverged. I only figured that the new lava would cool ~3 m deep since I was calculating the heat generated per day. But you are right we would need to account for much deeper cooling.

I am not sure that heat from below maybe 10km would actually be absorbed into the ocean though? Wouldn't it be more likely to go into surrounding rocks? But even if only half of the heat made it to the oceans it would still raise the temperature by 7,000K.

radiogenic heat (most heat producing radioisotopes are concentrated in continental crust)

I am interested in your thoughts regarding this portion of the problem. In order for the plates to move at the proposed speed, the mantle would have to have convection currents that increased proportionally. Theoretically this heat could come from a rapid acceleration of radiogenic decay rates (a favorite of creationist theories). Would it theoretically be possible to produce such convection currents? What kind of heat differential would be required?

I hope I haven't made any mistakes.

Thanks for clearing up mine, though ... My numbers seemed extremely low, but I couldn't see where I erred.

HBD


Whoever calls me ignorant shares my own opinion. Sorrowfully and tacitly I recognize my ignorance, when I consider how much I lack of what my mind in its craving for knowledge is sighing for. But until the end of the present exile has come and terminated this our imperfection by which "we know in part," I console myself with the consideration that this belongs to our common nature. - Francesco Petrarca

"Nothing is easier than to persuade people who want to be persuaded and already believe." - another Petrarca gem.


This message is a reply to:
 Message 25 by TrueCreation, posted 12-15-2012 2:24 AM TrueCreation has responded

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NoNukes
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Posts: 9550
From: Central NC USA
Joined: 08-13-2010
Member Rating: 3.0


Message 27 of 102 (684069)
12-15-2012 11:34 AM
Reply to: Message 25 by TrueCreation
12-15-2012 2:24 AM


Re: Back of envelope calculation
Frictional heat dissipation isn't necessarily a problem for heat budget problems because once you initiate melting slip efficiency will increase.

This does not seem correct to me. If slip efficiency increases, you still have the problem of reducing the speed of fast moving plates to the current slow rates in the same small amount of time. The same amount of kinetic energy is still being converted to heat. Reducing friction to nil just makes it harder to argue that plate movement was once much faster than today.


Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846)

The apathy of the people is enough to make every statue leap from its pedestal and hasten the resurrection of the dead. William Lloyd Garrison.

If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning. Frederick Douglass


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 Message 25 by TrueCreation, posted 12-15-2012 2:24 AM TrueCreation has responded

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TrueCreation
Inactive Member


Message 28 of 102 (684073)
12-15-2012 12:27 PM
Reply to: Message 27 by NoNukes
12-15-2012 11:34 AM


Re: Back of envelope calculation
The energy released from reducing the velocity of the mass of the oceanic and continental lithosphere (~2.5*10^23 kg) from 0.3 m/sec to 0 m/sec is about 10^22 J. Although this is a large amount of energy which almost certainly should have left a signature in geophysical observations, this could be dissipated over a large volume in the mantle by viscous forces (not released into the oceans) and is about 7 orders of magnitude less than heat content removed by lithospheric cooling.
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NoNukes
Member
Posts: 9550
From: Central NC USA
Joined: 08-13-2010
Member Rating: 3.0


Message 29 of 102 (684075)
12-15-2012 1:01 PM
Reply to: Message 23 by herebedragons
12-10-2012 10:35 AM


Re: Earthquakes
Why does a YEC model need to have land masses gathered into one place to begin with?

It wouldn't except that YEC is linked tightly to a literal, inerrant Bible. Having the continents in one place explains things like how the animals got home after the great flood and how humans scattered after the Tower of Babel was destroyed.


Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846)

The apathy of the people is enough to make every statue leap from its pedestal and hasten the resurrection of the dead. William Lloyd Garrison.

If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning. Frederick Douglass


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 Message 23 by herebedragons, posted 12-10-2012 10:35 AM herebedragons has not yet responded

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NoNukes
Member
Posts: 9550
From: Central NC USA
Joined: 08-13-2010
Member Rating: 3.0


Message 30 of 102 (684076)
12-15-2012 1:05 PM
Reply to: Message 28 by TrueCreation
12-15-2012 12:27 PM


Re: Back of envelope calculation
and is about 7 orders of magnitude less than heat content removed by lithospheric cooling.

That's fine. But I'm really asking about the effect of slip efficiency on the generation of heat. Perhaps my question is irrelevant?


Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846)

The apathy of the people is enough to make every statue leap from its pedestal and hasten the resurrection of the dead. William Lloyd Garrison.

If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning. Frederick Douglass


This message is a reply to:
 Message 28 by TrueCreation, posted 12-15-2012 12:27 PM TrueCreation has responded

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