Did the moon cause the 8.3 magnitude earthquake off Chile

[chum]

Anyone else hearing a lot of nonsense about how the full moon caused the earthquake or that full moon earthquakes are the most powerful?

[Kestrel]

Anyone else hearing a lot of nonsense about how the full moon caused the earthquake or that full moon earthquakes are the most powerful?

An easily predicted form of lunacy.

Sometime later today a fundamentalist preacher will say the earthquake was cause by the immorality of the people of Chile.

[Travis]

An easily predicted form of lunacy.

Sometime later today a fundamentalist preacher will say the earthquake was cause by the immorality of the people of Chile.

Literally.

[Rodney]

Anyone else hearing a lot of nonsense about how the full moon caused the earthquake or that full moon earthquakes are the most powerful?
Now that you mention it:

The 8.8 magnitude earthquake that struck Chile was one the most powerful in recorded history. The Chile earthquake hit on Saturday February 27 at 06:34 GMT. A curious coincidence was the earthquake occurred just before the full moon’s perigee. Perigee is when the moon is at its closest point to earth. The moon’s distance to the earth varies during its orbit and sometimes is at its closest (perigee), sometimes at its furthest (apogee). Perigee was 18 hours later, on February 27 at 21:41 GMT. At the same time the moon was waxing 99% full.

Adding to the strangeness was a magnitude 6.9 earthquake that hit Japan a day earlier at 20:31 GMT Friday.

The moon affects our tides. The tides are strongest when the moon is full, lined up straight with the earth and sun. The result is something called a spring tide, which is when the tides are highest. When the moon is at perigee its gravitational strength is also nearly 50% greater.

Did the moon’s gravity trigger the Chile earthquake? It seems like an awfully strange coincidence. There have been theories that when the planets line up in our solar system, it will create disastrous earthquakes and earth changes. This has never happened since the planets are too far away for their gravity to have an influence on the earth. The sun and moon are a different story, as their influence on our tides show. When the conditions are just right, perhaps the stress of tidal forces on our crust can trigger the earth to shake.

See http://occultview.com/2010/02/28/chile-earthquake-caused-by-full-moon-at-perigee

Any studies refuting this idea?

[BirdyBuddy]

You do realize there are earthquakes every single hour of every single day somewhere in the world, right?

Looking at these historic earthquakes, all magnitude 5.8 and above, I can see no correlation between earthquakes and a full moon:

http://earthquake.usgs.gov/earthquakes/world/historical.php

In fact, the recent Haiti quake, nearly as severe in magnitude but causing substantially more damage and death, was two days before a new moon.

Yes, its coincidence.

[Rodney]

You do realize there are earthquakes every single hour of every single day somewhere in the world, right?

Looking at these historic earthquakes, all magnitude 5.8 and above, I can see no correlation between earthquakes and a full moon:

http://earthquake.usgs.gov/earthquakes/world/historical.php

In fact, the recent Haiti quake, nearly as severe in magnitude but causing substantially more damage and death, was two days before a new moon.
I'm looking for studies, not opinions.

[BirdyBuddy]

Fortunately for you it's not an opinion. Just a wonderful collection of facts.

[Rodney]

Fortunately for you it's not an opinion. Just a wonderful collection of facts.
Facts can be interpreted in a number of ways -- that's why studies analyzing those facts are necessary.

[BirdyBuddy]

No interpretation necessary. Did you even go look at the site linked? Why, even you, with those facts, could do your own study!
Dates are all over the calendar, with no correlation to what phase the moon is in.

Look at the details listed for the recent Chilean quake:

http://earthquake.usgs.gov/earthquakes/eqinthenews/2010/us2010tfan/#details

Notice what's missing out of an abundance of data? The phase of the moon is not a piece of data that gets collected, as there is no correlation.

[BirdyBuddy]

And you didn't even address this:

You do realize there are earthquakes every single hour of every single day somewhere in the world, right?

You've made a claim there may be a connection. Now it's up to you to show evidence to support your claim. And, no. That link of yours includes only supposition, no facts.

[Rodney]

The phase of the moon is not a piece of data that gets collected, as there is no correlation.
That's certainly the conventional wisdom, but it could be wrong. Also, there's the matter of the earth-moon distance.

[BirdyBuddy]

Then pull out your evidence that suggests it's wrong. It's just not there. Nor is the distance a factor when the phase of the moon is not taken into account. If it were a factor, you bet your butt it would be noted and taken into account!

And you still fail to address this:
You do realize there are earthquakes every single hour of every single day somewhere in the world, right?

[BirdyBuddy]

Okay all, I apologize for the derail. If it needs to get split off to it's own thread please do so.

I'm just glad the Chilean JREF contingent are all okay. I'll go find something to drink in memory of your lost collection Patricio!

[Rodney]

Then pull out your evidence that suggests it's wrong. It's just not there. Nor is the distance a factor when the phase of the moon is not taken into account. If it were a factor, you bet your butt it would be noted and taken into account!
According to -- http://news.nationalgeographic.com/news/2005/05/0523_050523_moonquake.html --

The moon's orbit is inclined in relation to the Earth, causing the moon's position in the sky to nod north and south on an 18.6-year cycle.

Is the observed correlation between the moon's position in its 18.6-year cycle (or any other lunar phase) and earthquake activity a coincidence or something more? That question, [Geoff] Chester [an astronomer and public affairs officer with the U.S. Naval Observatory] in Washington, D.C.said, is best answered by the U.S. Geological Survey.

"There's no evidence to support that," said John Bellini, a geophysicist with the survey's National Earthquake Information Center in Golden, Colorado. "There were some studies in the past that tried to link lunar effects to seismicity [the relative frequency and distribution of earthquakes] and there was nothing found."

[However] James O. Berkland is a Glen Ellen, California-based geologist and editor of Syzygy—An Earthquake Newsletter. He believes the gravitational tugs of the moon, sun, and other planets can influence earthquake activity. Berkland said he has accurately predicted tremors based on factors such as syzygy.

"Syzygy" refers to the alignment of three celestial objects. Syzygy of the sun, Earth, and moon occur twice a month, at the full and new moons. At such times, gravitational forces are at a maximum, especially when the bodies are close together, Berkland said.

At least two major quakes may support Berkland's theory. The December 26, 2004, magnitude 9.1 in Sumatra, Indonesia, occurred on the day of a full moon. Likewise, the March 27, 1964, magnitude 9.2 earthquake in Alaska occurred on the day of maximum high tide.

And you still fail to address this: You do realize there are earthquakes every single hour of every single day somewhere in the world, right?
Yes, but that doesn't answer the question about a possible correlation between the position of the moon relative to the earth and earthquakes. No one is saying that earthquakes can occur only when the moon is full or closer to the earth than normal, but that does not rule out a possible correlation. Mr. Bellini refers to some prior studies of this issue that he says were negative, and so maybe someone here can locate those studies.

[Chaos]

According to -- http://news.nationalgeographic.com/news/2005/05/0523_050523_moonquake.html --

The moon's orbit is inclined in relation to the Earth, causing the moon's position in the sky to nod north and south on an 18.6-year cycle.

Is the observed correlation between the moon's position in its 18.6-year cycle (or any other lunar phase) and earthquake activity a coincidence or something more? That question, [Geoff] Chester [an astronomer and public affairs officer with the U.S. Naval Observatory] in Washington, D.C.said, is best answered by the U.S. Geological Survey.

"There's no evidence to support that," said John Bellini, a geophysicist with the survey's National Earthquake Information Center in Golden, Colorado. "There were some studies in the past that tried to link lunar effects to seismicity [the relative frequency and distribution of earthquakes] and there was nothing found."

[However] James O. Berkland is a Glen Ellen, California-based geologist and editor of Syzygy—An Earthquake Newsletter. He believes the gravitational tugs of the moon, sun, and other planets can influence earthquake activity. Berkland said he has accurately predicted tremors based on factors such as syzygy.

"Syzygy" refers to the alignment of three celestial objects. Syzygy of the sun, Earth, and moon occur twice a month, at the full and new moons. At such times, gravitational forces are at a maximum, especially when the bodies are close together, Berkland said.

At least two major quakes may support Berkland's theory. The December 26, 2004, magnitude 9.1 in Sumatra, Indonesia, occurred on the day of a full moon. Likewise, the March 27, 1964, magnitude 9.2 earthquake in Alaska occurred on the day of maximum high tide.


Yes, but that doesn't answer the question about a possible correlation between the position of the moon relative to the earth and earthquakes. No one is saying that earthquakes can occur only when the moon is full or closer to the earth than normal, but that does not rule out a possible correlation. Mr. Bellini refers to some prior studies of this issue that he says were negative, and so maybe someone here can locate those studies.

So there´s no evidence for your claims, which proves that you are right? Sweet.

[lector]

At least two major quakes may support Berkland's theory. The December 26, 2004, magnitude 9.1 in Sumatra, Indonesia, occurred on the day of a full moon. Likewise, the March 27, 1964, magnitude 9.2 earthquake in Alaska occurred on the day of maximum high tide.


So that makes at least four now.

[I Ratant]

...
[However] James O. Berkland is a Glen Ellen, California-based geologist and editor of Syzygy—An Earthquake Newsletter. He believes the gravitational tugs of the moon, sun, and other planets can influence earthquake activity. Berkland said he has accurately predicted tremors based on factors such as syzygy.

"Syzygy" refers to the alignment of three celestial objects. Syzygy of the sun, Earth, and moon occur twice a month, at the full and new moons. At such times, gravitational forces are at a maximum, especially when the bodies are close together, Berkland said.

At least two major quakes may support Berkland's theory. The December 26, 2004, magnitude 9.1 in Sumatra, Indonesia, occurred on the day of a full moon. Likewise, the March 27, 1964, magnitude 9.2 earthquake in Alaska occurred on the day of maximum high tide.


...
" two major quakes..." 40 years apart, related to a system that has had 960 syzygies in that period.
It is to laugh!

[Rodney]

So there´s no evidence for your claims, which proves that you are right? Sweet.
Unlike BirdyBuddy, I haven't made any claims. I take the (apparently radical, to some here) position that an idea should not be dismissed without examining it.

[Chaos]

Unlike BirdyBuddy, I haven't made any claims. I take the (apparently radical, to some here) position that an idea should not be dismissed without examining it.

It *has* been examined, and *then* dismissed. The freaking article you quoted showed that it has been examined:

"There's no evidence to support that," said John Bellini, a geophysicist with the survey's National Earthquake Information Center in Golden, Colorado. "There were some studies in the past that tried to link lunar effects to seismicity [the relative frequency and distribution of earthquakes] and there was nothing found."


There´s nothing radical about examining an idea before dismissing it. What is apparently radical to you, however, is accepting that an idea you like has no basis in reality, and should be dismissed.

[BirdyBuddy]

Unlike BirdyBuddy, I haven't made any claims. I take the (apparently radical, to some here) position that an idea should not be dismissed without examining it.
Actually, you very clearly made a claim and failed to support it. The hypothesis has been examined by many sources, some of which you even quote, and has been let to lie as there has not been found a direct correlation. I merely used fact to dispute your claim. That should be how it works.

Please keep the unnecessary personalization out of it.

I can say that it's not a radical idea, only an ignorant one if you do not take facts into account.

If you're so convinced there is a correlation, then you can quickly do the numbers yourself. Use the USGS site, or a site of your choosing, go through the dates and make a quick chart. It's there for you to see. You only need to go look.

[Rodney]

Actually, you very clearly made a claim and failed to support it.
Please tell me the post in which I "very clearly made a claim and failed to support it."

[BirdyBuddy]

Please tell me the post in which I "very clearly made a claim and failed to support it."

Your first post in this thread (I believe) is the claim and the link you included there was your first attempt at support it. You know - the one we've bantering about:

http://forums.randi.org/showpost.php?p=5668654&postcount=87

Sorry no, you don't get to back-peddle here. Yes, you - by posting it you've implied you thought it had some merit, it's your claim. You've answered to posts refuting it. If you had any doubt about what it was saying, it's likely you would not have posted it in the first place. If you don't have some belief in what you posted you should have said so as a disclaimer at the start, which you didn't do.

Feel free to retract it at any time. No one will hold it against you.

[Rodney]

Your first post in this thread (I believe) is the claim and the link you included there was your first attempt at support it. You know - the one we've bantering about:

http://forums.randi.org/showpost.php?p=5668654&postcount=87

Sorry no, you don't get to back-peddle here. Yes, you - by posting it you've implied you thought it had some merit, it's your claim. You've answered to posts refuting it. If you had any doubt about what it was saying, it's likely you would not have posted it in the first place. If you don't have some belief in what you posted you should have said so as a disclaimer at the start, which you didn't do.

Feel free to retract it at any time. No one will hold it against you.
The post that you cite was responding to chum's post, which asked: "Anyone else hearing a lot of nonsense about how the full moon caused the earthquake or that full moon earthquakes are the most powerful?"

I responded by saying: "Now that you mention it:" and posted a link that suggested the idea that chum and you regard as "a lot of nonsense" might have merit, although it concluded equivocally: "When the conditions are just right, perhaps the stress of tidal forces on our crust can trigger the earth to shake." I then asked: "Any studies refuting this idea?"

So, I never made a claim -- I'm simply interested in exploring the idea that the position of the moon may affect earthquakes.

[Chaos]

The post that you cite was responding to chum's post, which asked: "Anyone else hearing a lot of nonsense about how the full moon caused the earthquake or that full moon earthquakes are the most powerful?"

I responded by saying: "Now that you mention it:" and posted a link that suggested the idea that chum and you regard as "a lot of nonsense" might have merit, although it concluded equivocally: "When the conditions are just right, perhaps the stress of tidal forces on our crust can trigger the earth to shake." I then asked: "Any studies refuting this idea?"

So, I never made a claim -- I'm simply interested in exploring the idea that the position of the moon may affect earthquakes.

How about you go exploring that idea, then? I mean, instead of expecting us to do your homework?

And how about you actually read that link you provided - you know, the one where it says that your idea is not supported by evidence?

[Rodney]

How about you go exploring that idea, then? I mean, instead of expecting us to do your homework?
I intend to explore the idea, but I don't want to re-invent the wheel, if studies have already been done regarding this issue.

And how about you actually read that link you provided - you know, the one where it says that your idea is not supported by evidence?
That link quotes one geophysicist who says that there is nothing to the idea and a geologist who says that there is something to it.

[BirdyBuddy]

You can keep your "merely interested" position, but the fact is that you posted a quote and link to what you think has merit, and responded to replies by posting more quotes trying to defend your interest.

You continue to defend the idea by refusing to view easily accessible data that refutes your assertion.

Though you may not have come up with the idea originally, the fact that you keep sticking with it shows you have belief in what it states. But don't worry, nobody has mistaken it as yours if that's what's bothering you.

You have accepted the idea and brought it to this thread - that makes it your claim, regardless what you would like to call it.

[Chaos]

I intend to explore the idea, but I don't want to re-invent the wheel, if studies have already been done regarding this issue.

Then go and freaking read those studies, instead of demanding that we do you homework for you.

Your good old truther-inspired "just asking questions" shtick isn´t going to fool anyone. You believe what you believe, but don´t have the guts to admit it.

That link quotes one geophysicist who says that there is nothing to the idea and a geologist who says that there is something to it.

The link quotes one guy who says there is no evidence for this - no evidence for the claim means the claim needs not be taken serious.

The link also quotes another guy who says he believes in this claim, and claims to have predicted earthquakes - yet we never hear of anyone ever predicting an earthquake before it happens. So, unless that second guy presents evidence - not beliefs, not claims, but good, old-fashioned solid evidence - I´m not going to take him serious either.

[Rodney]

You continue to defend the idea by refusing to view easily accessible data that refutes your assertion.
First, I have not made any assertion regarding whether the position of the moon relative to the earth affects earthquakes. Second, assuming I had made such an assertion, how does the data that you have presented refute it?

[Chaos]

First, I have not made any assertion regarding whether the position of the moon relative to the earth affects earthquakes. Second, assuming I had made such an assertion, how does the data that you have presented refute it?

First, yes you have made that assertion; your "just bringing up stuff" trick doesn´t fool anyone here.

Second, since you have made that assetion, it is you who has to prove it, not anyone else who has to disprove it.

[Bindamel]

Someone check my math here, because Excel's binomial calculation always feels reversed to me:

There are 15 earthquakes on Wiki that are 8.6 or greater magnitude. I used http://aa.usno.navy.mil/data/docs/RS_OneDay.php to determine the phase of the moon / nearest new or full moon.

Of those two happen on a full or new moon (listed above). The likelihood of two or more earthquakes of the 15 happening on a full or new moon (I used 2/28 as the individual probability) is 0.291

One other happened within 1 day of a full or new moon (The 2010 Chile earthquake). The likelihood of three or more earthquakes of the 15 happening within 1 day of a full or new moon (6/28) is 0.654

Six within two days (adding 11/25/1833, Indonesia; 11/1/1755, Portugal; 8/15/1950, China), so individual probability is 10/28, and likelihood of six or more is 0.459.

Finally, four others happen within three days, so that's individual probability of 14/28 (starts to get less interesting there, doesn't it) and likelihood of 10 or more is 0.151.

I will admit, as I was doing it, I thought I was seeing patterns, but as soon as I did the math, they all went away. Go Math!

[Minadin]

http://imgs.xkcd.com/comics/purity.png

And:

http://imgs.xkcd.com/comics/certainty.png

[Skeptic Ginger]

Someone check my math here, because Excel's binomial calculation always feels reversed to me:

There are 15 earthquakes on Wiki that are 8.6 or greater magnitude. I used http://aa.usno.navy.mil/data/docs/RS_OneDay.php to determine the phase of the moon / nearest new or full moon.

Of those two happen on a full or new moon (listed above). The likelihood of two or more earthquakes of the 15 happening on a full or new moon (I used 2/28 as the individual probability) is 0.291

One other happened within 1 day of a full or new moon (The 2010 Chile earthquake). The likelihood of three or more earthquakes of the 15 happening within 1 day of a full or new moon (6/28) is 0.654

Six within two days (adding 11/25/1833, Indonesia; 11/1/1755, Portugal; 8/15/1950, China), so individual probability is 10/28, and likelihood of six or more is 0.459.

Finally, four others happen within three days, so that's individual probability of 14/28 (starts to get less interesting there, doesn't it) and likelihood of 10 or more is 0.151.

I will admit, as I was doing it, I thought I was seeing patterns, but as soon as I did the math, they all went away. Go Math!Your sample size isn't large enough to show a very small effect. And you should be looking at time of day for the quake, like during highest crustal deformation, not just the day of the lunar cycle.

Mantle/plate movements: very big effect.
Moon and Sun gravitational tidal pull: very small effect, but not necessarily no effect.

The other thing to consider is, are quakes more common when there is any tidal pull vs no pull? In other words, should we only look at the strongest tides? How about looking at the relationship between earthquakes and 12 hour high tide pattern?

These smaller effects are not always addressed when geologists are dismissing the major tidal pull myth.

It's hard to believe terrestrial tides would not have an effect on plate shifting events.

Wiki on terrestrial tides: (http://en.wikipedia.org/wiki/Tide)Earth tides
Earth tides or terrestrial tides affect the entire Earth's mass, which acts similarly to a liquid gyroscope with a very thin crust. The Earth's crust shifts (in/out, east/west, north/south) in response to lunar and solar gravitation, ocean tides, and atmospheric loading. While negligible for most human activities, terrestrial tides' semidiurnal amplitude can reach about 55 centimetres (22 in) at the equator—15 centimetres (5.9 in) is due to the Sun—which is important in GPS calibration and VLBI measurements. Precise astronomical angular measurements require knowledge of the Earth's rotation rate and nutation, both of which are influenced by earth tides. The semi-diurnal M2 Earth tides are nearly in phase with the Moon with a lag of about two hours.[citation needed]
Some particle physics experiments must adjust for terrestrial tides.[48] For instance, at CERN and SLAC, the very large particle accelerators account for terrestrial tides. Among the relevant effects are circumference deformation for circular accelerators and particle beam energy.[49][50] Since tidal forces generate currents in conducting fluids in the Earth's interior, they in turn affect the Earth's magnetic field. Earth tides have also been linked to earthquakes.[51]

[51]: Tidal triggering of earthquakes precursory to the recent Sumatra megathrust earthquakes of 26 December 2004 (Mw 9.0), 28 March 2005 (Mw 8.6), and 12 September 2007 (Mw 8.5) (http://www.agu.org/pubs/crossref/2010/2009GL041581.shtml)Sachiko Tanaka
National Research Institute for Earth Science and Disaster Prevention, Tsukuba, Japan

I observed tidal triggering of earthquakes precursory to the three giant earthquakes occurring off Sumatra on 26 December 2004 (Mw 9.0), 28 March 2005 (Mw 8.6), and 12 September 2007 (Mw 8.5). I measured the correlation between the Earth tide and earthquake occurrence in and around the focal regions of these megathrust earthquakes. The result of statistical analysis indicates that a high correlation appeared for several to ten years preceding the occurrence of the large earthquakes. The correlation vanished after the main events. The frequency distribution of tidal phase angles in the pre-event period exhibited a peak near the angle where the tidal shear stress is at its maximum to accelerate the fault slip. This implies that the high correlation observed in the pre-seismic stage is not a stochastic chance but is likely a physical consequence of the tidal stress change.

[Soapy Sam]

the relationship between earthquake magnitude and frequency seems to follow a power law model. Nobody knows why.
http://en.wikipedia.org/wiki/Gutenberg%E2%80%93Richter_law
We might expect that big quakes would be rare events following long periods of stress build up- and that does rather look true of transcurrent surface fault quakes like the San Andreas, but quakes associated with a slab inking into the mantle clearly involve different force patterns and so might be expected to have a different scale / frequency distribution.
They don't. Which seems odd.

It seems reasonable that lunar tides in the lithosphere could (other things being equal) provide the "final straw" that might trigger sudden movement. This would require that the stresses affecting the slab were already at a maximum before failure when the lunar tide added yet another vector. That would explain why such events coincide rarely. To me, the hypothesis is feasible. If the tidal stress peaks monthly and the tectonic stresses take (say) 50 years to reach criticality, then each major quake will happen within two weeks of high tide...but then that's true even if there's no causal relationship at all. Until we have some way of knowing when the quake is "ready to happen", we can't test the hypothesis- but if we can learn how to measure lunar induced tidal stress in a sinking slab- and it happens to be greater than we expected, we just might have a warning system for some types of quake.

[Rodney]

Your sample size isn't large enough to show a very small effect. And you should be looking at time of day for the quake, like during highest crustal deformation, not just the day of the lunar cycle.

Mantle/plate movements: very big effect.
Moon and Sun gravitational tidal pull: very small effect, but not necessarily no effect.

The other thing to consider is, are quakes more common when there is any tidal pull vs no pull? In other words, should we only look at the strongest tides? How about looking at the relationship between earthquakes and 12 hour high tide pattern?
In fairness to Bindamel, I think he was doing a back of the envelope calculation to see whether there was an obvious correlation that leaped right out at him. But I agree with you that this is a complex issue, which also involves the earth-moon distance. That's why it would be instructive to locate and review any previous moon/earthquake studies that have been undertaken.

These smaller effects are not always addressed when geologists are dismissing the major tidal pull myth.

It's hard to believe terrestrial tides would not have an effect on plate shifting events.

Wiki on terrestrial tides: (http://en.wikipedia.org/wiki/Tide)

[51]: Tidal triggering of earthquakes precursory to the recent Sumatra megathrust earthquakes of 26 December 2004 (Mw 9.0), 28 March 2005 (Mw 8.6), and 12 September 2007 (Mw 8.5) (http://www.agu.org/pubs/crossref/2010/2009GL041581.shtml)
Hmm, Skeptic Ginger, you seem to be one of those radicals who wants to look at the evidence before denouncing the idea of a moon-earthquake connection as nonsense. Careful, now, you might be charged with heresy and excommunicated. :)

[Skeptic Ginger]

In fairness to Bindamel, I think he was doing a back of the envelope calculation to see whether there was an obvious correlation that leaped right out at him. ....I wasn't trying to be unfair, only to reply to his hypothesis. Peer review? ;)

[Bindamel]

I wasn't trying to be unfair, only to reply to his hypothesis. Peer review? ;)

Sure. :)

The only point I was trying to make is that any effect would be too small to be noticed in passing. The two "counterquotes" above included one saying no effect has been seen, and the other one saying that two earthquakes have happened on the same day as a full moon.

The two full moon guy is definitely cherry-picking, and the stats are just there to say, "No, that's not really all that unlikely, even if there is no effect."

[shadron]

One of the initial books to support this sort of theory was the 1974 The Jupiter Effect, by John Gribbin and Stephen Plagemann. Gribbin later repudiated the book, saying he'd been too clever by half. Even Isaac Asimov wrote a blurb for the book, which goes to show what desire to keep on the best side of your publisher can do to discretion.

[BirdyBuddy]

First, I have not made any assertion regarding whether the position of the moon relative to the earth affects earthquakes. Second, assuming I had made such an assertion, how does the data that you have presented refute it?

Still refuse to look at the links, haven't you? Why don't you do some of your own homework and show us how the USGS data could possibly support your claim. As it stands, it doesn't.

Your assertion, your claim, is the post you presented. That's very clear. If you're not willing to stand behind the post you made, then retract it.

Or, even better yet! Show some evidence to support it (which you have not done), then we can continue to have a dialog. There have been several excellent posts in this thread by members willing to do the basic research you have refused to do.

If it's so important for you to have the last word, please feel free. But I would very much prefer to see evidence rather than back-peddling.

[Carefulplease]

In fact, the recent Haiti quake, nearly as severe in magnitude but causing substantially more damage and death, was two days before a new moon.

Yes, its coincidence.

Spring tides occur both around new and full moon, so that that's not an effective argument. If there is an effect on quakes, we should expect a correlation with both new and full moon and an anti-correlation with first and third quarter.

[Carefulplease]

Strong Earth Tides Can Trigger Earthquakes, UCLA Scientists Report

http://www.sciencedaily.com/releases/2004/10/041022103948.htm

[MG1962]

Rodney, in exploring the Moons ability to trigger earthquakes there are a couple of things to consider. First what was the mechanism that created the earthquake in the first place. Not all earthquakes are considered equal. Nor is the mechanism for creation of an earthquake the same. The second thing is creating the correlation between the orbital mechanics of the Moon and the event.

By far the hardest is the second element. The Moon produces continual and shifting stress on the Earths crust on a daily basis. The continental plates move up and down some six inches a day. So imagine the world as a tennis ball being continually squeezed
　
Because of this constant shifting, you can never pin down that earthquake X was caused by the Moon being position Y with any certainty. While the Moon in position Y may have added enough stress to the rock to finally make it slip, the Moon could quite possible have moved to position Z when the event itself happens
　
But back to the first point. If I am not mistaken, the latest earthquake occurred in a subduct ion zone. This is when one piece of crustal plate is slipping below another and plunging back into the Earth’s mantel. Normally the process is fairly smooth, but occasionally the descending plate gets hung up or snagged on the plate above it
　
This type of movement is gravity based. the crust slipping below the other is caused by that piece of ocean floor becoming water logged and dragging itself down. So the Moon passing over each day could be compared to your tongue working on something caught between your teeth. You might pick at the item for ages before it suddenly just comes loose
　
Same issue with the crust. The constant rising and lowering of the upper plate, combined with the Earths gravity pulling at the lower plate, could just disengage the two layers of crust and allow the accumulated movement to occur all at once
　
Science does not spend a lot of time on this problem simply because the Moon’s influence never stops. It is not like a switch that is thrown from the off to the on position. So in terms of how much energy the Moon is adding to an event, we simply do not have enough data on various geological events to know what might have happened if the Moon was not present.

[DSo]

Everything else being equal ... I'd expect the greatest tidal influence on the crust to be during a new moon. Both Sun and Moon are on the same side of the earth and the gravitational vectors are additive.

[MG1962]

Everything else being equal ... I'd expect the greatest tidal influence on the crust to be during a new moon. Both Sun and Moon are on the same side of the earth and the gravitational vectors are additive.

I would agree with you - however the apogee of the Moon would be a major factor

[MatildaGage]

The apocalyptic fundies are claiming the recent earthquakes' activity, causing the planet to shift, is a sign of the end times.

It also caused time itself to change. Oh, and the intensity of earthquakes is getting worse too, a sure sign of Armageddon.

http://forums.armageddononline.org/earthquake-may-have-t23950.html? (http://forums.armageddononline.org/earthquake-may-have-t23950.html?)

http://rapturealert.blogspot.com/2010/03/chile-quake-earths-axis-moved.html
:duck:
*off to hoard water, guns, duct tape, and accept Jesus as my personal savior*

[kalen]

I would believe the moon has far more to do with earthquakes than say ... HAARP.

[ServiceSoon]

I would agree with you - however the apogee of the Moon would be a major factor
"The orbit of the Moon is very nearly circular." (http://csep10.phys.utk.edu/astr161/lect/time/moonorbit.html)
Edit" You're actually correct about the distance, but the perigee occurs when a new moon is present around June/July of this year. So there goes your theory.

I'd agree with MachineGun1962 (I'm guessing?) - except wouldn't the pull of the sun negate the pull of the moon?

[I Ratant]

40? years ago, all the planets and the Moon were on the "same side" of the earth (in a 90 degree sector), yet nothing moved all that much, if memory serves.

[MG1962]

"The orbit of the Moon is very nearly circular." (http://csep10.phys.utk.edu/astr161/lect/time/moonorbit.html)
Edit" You're actually correct about the distance, but the perigee occurs when a new moon is present around June/July of this year. So there goes your theory.

I'd agree with MachineGun1962 (I'm guessing?) - except wouldn't the pull of the sun negate the pull of the moon?

LOL - no not machine gun.....just an old nick name based around my real name. But back to the point. I dont believe causality can be atributed to a specifice Earthquake event, but I believe the Moon does add energy to the final release

Possibly one day someone will revisit this with enough computing power to model the stresses and see how much the Moon is or is not a factor

[Skeptic Ginger]

Sure. :)

The only point I was trying to make is that any effect would be too small to be noticed in passing. The two "counterquotes" above included one saying no effect has been seen, and the other one saying that two earthquakes have happened on the same day as a full moon.

The two full moon guy is definitely cherry-picking, and the stats are just there to say, "No, that's not really all that unlikely, even if there is no effect."It's hard to deny the fact the lunar tide effect on the land mass would affect plate slipping at least a little. It is rather interesting just how much the crust lifts up like the ocean tides. How would this physical warping of the plates not have at least a small effect on triggering earthquakes which were at their maximum stress?

The problem is people have been asking the wrong question. Most people just look at whether there are more quakes on full or new Moons.

The data one really needs to look at is the relationship between daily tidal maximums and quakes, not just maximum tides. And, one needs to look for a small effect, not a large one.

[Carefulplease]

Everything else being equal ... I'd expect the greatest tidal influence on the crust to be during a new moon. Both Sun and Moon are on the same side of the earth and the gravitational vectors are additive.

Tidal forces on an extended three dimensional body are represented by a tensor, not a vector. The differential effect in the radial component is one of stretching whatever the sense of the vector pull. So, the tidal effects on (the differential pull on opposite sides of) the Earth from both the Sun and the Moon add up even when the vectors are opposite.

IOW, The full Moon, on one side, pulls the nearest part of the Earth more than it pull the opposite part, thus stretching it. The Sun cancels some of the pull from the other direction but merely adds to the net differential and thus actually increases the stretching effect.

[I Ratant]

From my back door, I can see the airplane storage yard at Mohave, where old airliners go on their last flights before becoming pots and pans and Toyotas.
Some days, I can see more of the foreground just past the rise between me and Mohave.
I've wondered if that is due to stretching or bulging of the earth at different times.
The San Andreas fault surfaces about a 1/2 mile behind where I live, on its north wrinkle, and the Garlock fault passes near Mohave.
All the pavement locally shows continuous signs of earth movement.

[CORed]

Everything else being equal ... I'd expect the greatest tidal influence on the crust to be during a new moon. Both Sun and Moon are on the same side of the earth and the gravitational vectors are additive.

Actually it's new moon and full moon. Tides are caused by the difference in pull between opposite side of the earth. The side closest to the moon (or sun) is pulled more strongly than the side opposite. This causes a "stretching" stress on the earth. This is why in most places there are two high tides per lunar day. When the sun and moon are lined up, whether on the same side (new moon) or opposite sides (full moon), the solar tide is added to the stronger lunar tide.

[Skeptic Ginger]

Actually it's new moon and full moon. Tides are caused by the difference in pull between opposite side of the earth. The side closest to the moon (or sun) is pulled more strongly than the side opposite. This causes a "stretching" stress on the earth. This is why in most places there are two high tides per lunar day. When the sun and moon are lined up, whether on the same side (new moon) or opposite sides (full moon), the solar tide is added to the stronger lunar tide.

Tides, San Simeon, CA Feb 14th New Moon
Low 3:48 AM 1.8
High 9:47 AM 5.2
Low 4:31 PM 0.0
High 10:55 PM 4.4

Tides, San Simeon, CA Feb 28th Full Moon
Low 3:16 AM 0.9
High 9:22 AM 5.9
Low 3:56 PM -0.7
High 10:15 PM 5.1

Tides for San Simeon March 15, 2010, New Moon
Low 4:35 AM 1.0
High 10:36 AM 4.7
Low 4:47 PM 0.6
High 11:02 PM 4.8

Tides for San Simeon starting with March 30, 2010. Full Moon
Low 5:02 AM -0.5
High 11:14 AM 4.7
Low 4:55 PM 0.7
High 11:08 PM 5.8


It appears there is a greater effect on the full Moon when the Moon and Sun are opposite.

[Carefulplease]

It appears there is a greater effect on the full Moon when the Moon and Sun are opposite.

That shouldn't generally be the case. Among many confounding factors are the facts that lunar and terrestrial orbits aren't circular. Lunar tides are stronger close to the lunar perigee and solar tides are stronger close to the perihelion.

[Soapy Sam]

From my back door, I can see the airplane storage yard at Mohave, where old airliners go on their last flights before becoming pots and pans and Toyotas.
Some days, I can see more of the foreground just past the rise between me and Mohave.
I've wondered if that is due to stretching or bulging of the earth at different times.
The San Andreas fault surfaces about a 1/2 mile behind where I live, on its north wrinkle, and the Garlock fault passes near Mohave.
All the pavement locally shows continuous signs of earth movement.

Atmospheric refraction effect more likely.
Is your insurance up to date?

[I Ratant]

Atmospheric refraction effect more likely.
Is your insurance up to date?
.
Some days there's quite a noticeable mirage up there.
I have the latest approved FEMA earthquake bracing under the unit.
I'm safe.

[Skeptic Ginger]

That shouldn't generally be the case. Among many confounding factors are the facts that lunar and terrestrial orbits aren't circular. Lunar tides are stronger close to the lunar perigee and solar tides are stronger close to the perihelion.
I know I recall the tidal pull is greater on one or the other of these two events, new Moon or full Moon. But I couldn't recall which one. So I merely looked up the tide in a single location.

If the result was affected by the slightly elliptical orbit, then you are saying the Moon comes closer and further away in a 2 week cycle? That doesn't make sense.

I'm not saying I recall the details here, but I would think my data showing 2 lunar cycles would have answered the question.

[Cimerian]

Chilean 2010 earthquake was predicted pretty good, at least the location and the intensity, and its origin seems to be in the Earth. Certainly, scientist still don't know what triggers it. Here is the abstract of the publication of a study finished in 2007 and published late 2009, pay attention to the last sentence:

Interseismic strain accumulation measured by GPS in the seismic gap between Constitución and Concepción in Chile

J.C. Ruegg a, ∗, A. Rudloff b , C. Vigny b , R. Madariaga b , J.B. de Chabalier, J. Campos c , E. Kausel c , S. Barrientos c , D. Dimitrov d

The Concepción–Constitución area [35–37◦S] in South Central Chile is very likely a mature seismic gap, since no large subduction earthquake has occurred there since 1835. Three campaigns of global positioning system (GPS) measurements were carried out in this area in 1996, 1999 and 2002. We observed a network of about 40 sites, including two east–west transects ranging from the coastal area to the Argentina border and one north–south profile along the coast. Our measurements are consistent with the Nazca/South America relative angular velocity (55.9◦N, 95.2◦W, 0.610◦/Ma) discussed by Vigny et al. (2008, this issue) which predicts a convergence of 68 mm/year oriented 79◦N at the Chilean trench near 36◦S. With respect to stable South America, horizontal velocities decrease from 45 mm/year on the coast to 10 mm/year in the Cordillera. Vertical velocities exhibit a coherent pattern with negative values of about 10 mm/year on the coast and slightly positive or near zero in the Central Valley or the Cordillera. Horizontal velocities have formal uncertainties in the range of 1–3 mm/year and vertical velocities around 3–6 mm/year. Surface deformation in this area of South Central Chile is consistent with a fully coupled elastic loading on the subduction interface at depth. The best fit to our data is obtained with a dip of 16 ± 3◦, a locking depth of 55 ± 5 km and a dislocation corresponding to 67 mm/year oriented 78◦N. However in the northern area of our network the fit is improved locally by using a lower dip around 13◦. Finally a convergence motion of about 68 mm/year represents more than 10 m of displacement accumulated since the last big interplate subduction event in this area over 170 years ago (1835 earthquake described by Darwin). Therefore, in a worst case scenario, the area already has a potential for an earthquake of magnitude as large as 8–8.5, should it happen in the near future.

[Carefulplease]

I know I recall the tidal pull is greater on one or the other of these two events, new Moon or full Moon. But I couldn't recall which one. So I merely looked up the tide in a single location.

If the result was affected by the slightly elliptical orbit, then you are saying the Moon comes closer and further away in a 2 week cycle? That doesn't make sense.

I'm not saying I recall the details here, but I would think my data showing 2 lunar cycles would have answered the question.

The Moon is 364,397 km away (from the Earth's center) at perigee and 406,731 km away at apogee. The orbital period is 27.3 days. This is less than the 29.5 day synodic month (period from one full moon to the next) because of the Earth-Moon system yearly motion around the sun.

At apogee, the Earth-Moon distance thus increases (407-364)/364 = 11.8% from the perigee distance. Tidal force obeys an inverse cube law. Lunar tidal forces at apogee are thus 40% weaker than they are at perigee. This strengthening cycle will shift roughly every three months from one lunar phase to the next. And then I didn't factor the (somewhat smaller) solar tidal variations caused by the Earth's own orbital eccentricity. And there are very many other confounding factors linked to the Earth's axis inclination, variations in oceanic currents, local variations in ocean depth, etc.

http://en.wikipedia.org/wiki/Orbit_of_the_Moon

[Skeptic Ginger]

The Moon is 364,397 km away (from the Earth's center) at perigee and 406,731 km away at apogee. The orbital period is 27.3 days. This is less than the 29.5 day synodic month (period from one full moon to the next) because of the Earth-Moon system yearly motion around the sun.

At apogee, the Earth-Moon distance thus increases (407-364)/364 = 11.8% from the perigee distance. Tidal force obeys an inverse cube law. Lunar tidal forces at apogee are thus 40% weaker than they are at perigee. This strengthening cycle will shift roughly every three months from one lunar phase to the next. And then I didn't factor the (somewhat smaller) solar tidal variations caused by the Earth's own orbital eccentricity. And there are very many other confounding factors linked to the Earth's axis inclination, variations in oceanic currents, local variations in ocean depth, etc.

http://en.wikipedia.org/wiki/Orbit_of_the_MoonSo the difference between tidal maximum and minimum on full Moons and new Moons over 2 cycles is demonstrating the difference in the Sun's position, not the difference in the Moon's orbit.

And the tide readings I posted showed greater tides with the full Moon than the new Moon.

By all means, correct me if I'm wrong. I don't claim to know, I just looked up the data.

[shadron]

I know I recall the tidal pull is greater on one or the other of these two events, new Moon or full Moon. But I couldn't recall which one. So I merely looked up the tide in a single location.

If the result was affected by the slightly elliptical orbit, then you are saying the Moon comes closer and further away in a 2 week cycle? That doesn't make sense.

I'm not saying I recall the details here, but I would think my data showing 2 lunar cycles would have answered the question.

The difference is the diameter of Earth divided by the radius of its orbit: 7000/93000000 = 1 part in 100,000.

The moon's orbit has an ellipticity of around 12%. The ratio of apogee tide force to that of perigee would be (apogee/perigee)^2, or 25%. This additional bulge due to ellipticity moves around the Earth in an 8.8 year cycle.

The tide amplitude effect that moves around in a biweekly cycle is that of spring vs neap tides, which are caused by the moon and the sun alternately working with and across each other, twice per month.

At apogee, the Earth-Moon distance thus increases (407-364)/364 = 11.8% from the perigee distance. Tidal force obeys an inverse cube law. Lunar tidal forces at apogee are thus 40% weaker than they are at perigee. This strengthening cycle will shift roughly every three months from one lunar phase to the next.

I don't kniow where you got 40%, the ratio is 1.118^2 = 1.2499, or 25%. Right about the cycle; the location where the cycle maximizes also rotates around the Earth in 8.8 years.

[Carefulplease]

I don't kniow where you got 40%, the ratio is 1.118^2 = 1.2499, or 25%. Right about the cycle; the location where the cycle maximizes also rotates around the Earth in 8.8 years.

The square of the ratio yields only the difference in gravitational pull. The tidal force is the differential of this pull. Hence you must use 1.118^3 = 1.397. So, I said the tidal force was 40% weaker at the apogee but that was also a mistake. 1.397 is the correct ratio but the decrease rather is 1-(1/1.397)= 0.284 or 28%.

The 8.8 year cycle you mention isn't quite relevant so far as I can see, except inasmuch as it yields a small correction to the cycle I identified. This 8.8 year cycle is the period of recession of line of apsides. This is measured in the inertial frame defined by distant stars. The relevant cycle rather concerns the annual rotation of the Earth-Sun axis. It yields the roughly three month shift in spring tide to apogee conjunction that I mentioned. That is: if the full moon spring tide coincides with strong apogee lunar tidal strength at some point, then three months later, perigee lunar tidal strength will coincide with last quarter, and three month later with new moon.

[Carefulplease]

Tides, San Simeon, CA Feb 14th New Moon
Low 3:48 AM 1.8
High 9:47 AM 5.2
Low 4:31 PM 0.0
High 10:55 PM 4.4

Tides, San Simeon, CA Feb 28th Full Moon
Low 3:16 AM 0.9
High 9:22 AM 5.9
Low 3:56 PM -0.7
High 10:15 PM 5.1

Tides for San Simeon March 15, 2010, New Moon
Low 4:35 AM 1.0
High 10:36 AM 4.7
Low 4:47 PM 0.6
High 11:02 PM 4.8

Tides for San Simeon starting with March 30, 2010. Full Moon
Low 5:02 AM -0.5
High 11:14 AM 4.7
Low 4:55 PM 0.7
High 11:08 PM 5.8


It appears there is a greater effect on the full Moon when the Moon and Sun are opposite.

http://www.fourmilab.ch/earthview/pacalc.html

Lunar perigee and apogee diring that period occured at:
Feb 13 Apogee
Fev 27 Perigee
Mar 12 Apogee
Mar 28 Perigee

So, your new moon weak tides occurred within 1-3 days of apogee and your full moon relatively stronger tides occurred within 2 days of perigee. This nicely explains the difference. (Exactly at perigee, and with the moon less than full, high tides are over 6 feet high!)

On edit:
http://forums.randi.org/showthread.php?p=5698141#post5698141
http://moonphases.info/moon_phases.html

If you look for data at the same location during august 2009, the tendency is reversed. You get strong new moon spring tides and much weaker full moon spring tides. I didn't check for november but I expect roughly equal strength full moon and new moon spring tides. I hope this is convincing ;-)

[Skeptic Ginger]

The difference is the diameter of Earth divided by the radius of its orbit: 7000/93000000 = 1 part in 100,000.

The moon's orbit has an ellipticity of around 12%. The ratio of apogee tide force to that of perigee would be (apogee/perigee)^2, or 25%. This additional bulge due to ellipticity moves around the Earth in an 8.8 year cycle.I don't think you understood my comment.

The tide amplitude effect that moves around in a biweekly cycle is that of spring vs neap tides, which are caused by the moon and the sun alternately working with and across each other, twice per month.I posted the tides at the new and full Moons, not at the neap tides.

But it looks like Carefulplease is finally getting through.

[Skeptic Ginger]

http://www.fourmilab.ch/earthview/pacalc.html

Lunar perigee and apogee diring that period occured at:
Feb 13 Apogee
Fev 27 Perigee
Mar 12 Apogee
Mar 28 Perigee

So, your new moon weak tides occurred within 1-3 days of apogee and your full moon relatively stronger tides occurred within 2 days of perigee. This nicely explains the difference. (Exactly at perigee, and with the moon less than full, high tides are over 6 feet high!)

On edit:
http://forums.randi.org/showthread.php?p=5698141#post5698141
http://moonphases.info/moon_phases.html

If you look for data at the same location during august 2009, the tendency is reversed. You get strong new moon spring tides and much weaker full moon spring tides. I didn't check for november but I expect roughly equal strength full moon and new moon spring tides. I hope this is convincing ;-)OK, it's making sense now.