The Moon and the Moonie

Part I: The Moon

This is getting a bit old. Time and time again, someone bops along with the idea that the Moon or the sun causes an increase in seismicity. They climb up on their soapbox and thump their chest denouncing the world (that would be the rest of us) are blind to the obvious correlation. That we will all suffer ruination if we don’t heed their warnings or suffers some calamity akin to a slow and brutal death.

Hey, sounds like fun. Let’s play.

Here is a plot of all earthquakes greater than Magnitude 4.5 as listed on the USGS website from 1973 to 2010.

Image by GeoLurking.

Wow, that look a bit compelling. How about the power distribution across that same data?

Image by GeoLurking.

Well… that seals the deal. Right?

Not so fast.

First, I would like to point out that there is some research that points to a lunar influence in the activity of certain already seismically active regions, but that this research is founded on actual science. The effect is ephemeral and buried in noise. This is not intended to debunk that research, only to illustrate just how misleading some of the source data is, and how easy it is to jump to conclusions.

Now here is the nugget-o-truth that most people tend to miss:

The longer that the Moon spends at a specific location, the more likely it is that quakes will occur while it is at that location.

The Moon completes an orbit around the Earth about every 27.321 days. All orbits have a Perapsis (closest point on orbit) and an Apoapsis (furthest point). At perapsis the Moon is at it’s highest rate of speed at about 1.076 km/s.1 At apoapsis, it is moving at 0.964 km/s1. Obviously, this speed is not constant. The period of the Lunar orbit is 27.321582 days2 . The Moon goes through a full phase cycle in about 29.53 days3. That’s almost the same period… but it’s not. Couple this with the dynamics of an elliptical orbit, and you get this odd characteristic.

Image by GeoLurking.

This is the dwell time of the Moon on two separate phase cycles. Notice that the curves, though similar, do not match. This is due to the ‘not quite the same’ durations of the phase cycle and the orbital period. Also notice that the amount of time spent at the New and Full phases is longer than at mid phase.

Let’s take a look at several cycles in order to see if there is a pattern.

Image by GeoLurking.

Sure enough… that orange is the plot of several phase cycles. The blue is an average of what is seen at that phase over those same cycles. (the average of the orange curve). We can go a step further and run this through a curve fitting program in order to see if there is a function that matches.

Image by GeoLurking.

That’s pretty good… but note the end points, even though the curve is a good fit, it leave enough uncertainty on the ends to make it mostly useless. I provided the plot mainly since I pissed away about two and a half hours in Erueqa’s “Formulize” in order to find it. (it’s a really great program though).

Taking the idea of using the mean of the curve to calculate a correction factor, and using the 1000 bin average from the previous plot (the one with the orange and blue), we can apply that to the quake count curve.

Image by GeoLurking.

Err… where did the trends go? Okay, maybe the power curve will still show the significant signal.

Image by GeoLurking.

Hmm… not looking so good.

There is still an artifact in there… at least it seems to me like there is an artifact in there… but it’s small. So small that the last thing I would do would be to stand on a soap box preaching at people about it.

Part II: The Sun and the Moon

I realize that some people are adamant about the seismic connection with the Sun and the Moon. I also realize that I have pointed out a few issues with making this connection. One might argue that I was being very selective in presenting the data… okay, fair enough.

Here are some more plots that may, or may not, show a connection. You be the judge.

Image by GeoLurking.

Image by GeoLurking.

Image by GeoLurking.

Image by GeoLurking.

Nothing there that really jumps out at ya eh? Okay, a few more:

Image by GeoLurking.

Image by GeoLurking.

Do note that the apparent dwell time of the Sun at mid Winter and Mid Summer really stands out in that last plot. By the way, see those horizontal bands? Those are the latitudes of seismically active areas.


Image by GeoLurking.

Image by GeoLurking.

Again, the bands equate to known active areas… this time in longitude.

You may think me an ass for not believing in the Sun-Moon-Earth connection. That’s your prerogative. But unlike some, I actually went out and looked for myself. I’m not one to buy a pig in a poke. Personally, I don’t see it in the data. If your numeric skills are better, knock yourself out. I could stand to learn a thing or two while reading it. But if it’s BS, I’m not gonna buy it.





609 thoughts on “The Moon and the Moonie

  1. Hi Sissel,

    how do you get those videos of it, it is day time here, so could keep an eye on things for all of you

    • Hi Ursh,
      With a screen capture program it is easy to make videos. You can make a video from a webcam with a moving picture (like the Icelandic cams), but from a still picture (like the Etna cams) as well. – Here I captured 5 seconds (interval maybe too long) of every new picture from the webcam; that makes 5 seconds of every minute. I’m using SOM (pro version) now but there are many free programs too. You need to upload it to somewhere (like YouTube) and put a link here. Only YouTube video’s will appear automatically on this site.
      It would be great if nightshift people would capture the European night time volcano activities and serve us for breakfast! Oh I like the idea of breakfast being served…

      • thanks for that I copied it to a folder, my head isn’t in the right place at the moment and the pc is palying up, to cold, also I have another look for my old girl she disappeared again twice yesterday, I haven’t been able to find her, sometimes when their time is up they do that

  2. 4.9 – 2012/04/22 13:04:14, -5.896 105.518 26.8, SUNDA STRAIT, INDONESIA
    this is Krakatoa territory, there seems to be a lot of EQ in he vicinity and also on the subduction zone of it, usually in the 4-5 range

  3. Hi islander. I think it could be just you, me and the cat-hater still awake!! I would not like to have Etna anywhere uphill from me!!!

    • I love cats, have quiet a few, doesn’t mean they are allowed to run feral, neither are all my animals, a bit like kids, love them to bits, but am strict, come to think of it, I usually tell my customers the way you raise an animal is the same way as you do with husbands/partners, I always recommend desexing, one guy asked do humans live onger too if they are desexed, I told him, there is one way to find out.
      Etna is gone for a rest, see you later, it is oh so cold, had a front coming up from Anartica, rrr, was 13 at 10am now not even 10

  4. Wayyyy up there somewhere, Jupiter’s moon Io was mentioned. So I went looking. I did not see anything about its shape changing, which is what I wanted to learn more about, but I did find this:
    It asks: “What force is responsible for powering the volcanoes on Io.”
    It answers: “Tidal heating is the heating of the interior of one planetary body caused by stresses induced from the gravitational pull of another.” (References are but just a click away.)

    • Yes, saw BBC documentary on this long time ago. Io is rather tiny, pulled by two or more Gigants ? We have our smallish moon, with only part of our Earth Gravitational pull. It may make the Ocean and Solid Ground tidal waves and perhaps make some friction heat in the crust over very long time, or this may contribute to plate tetonics. Or it may not. I have no real knowledge of this.

    • The mass of Jupiter is 317.8 that of Earth which in turn is 81 times that of the Moon. Io orbits Jupiter (orbital radius) at 421,700 km. Our Moon orbits Earth at 384,748 km. Thus Jupiter exerts 21,428 times the gravitational pull on Io than the Moon does on the Earth. (Provided I got the maths right of course (M1/M2) / (OR1/OR2)^2 )

      The Jovian moon that exerts the greatest gravitational pull on Io is Europa, which comes within 249,200 km (based on semi-major axis. If Io is at apojove and Europa perijove, it’s slightly closer). As the mass of Europa is 65% that of our Moon, the gravitational pull it exerts on Io is ~1.5 times greater than the Moon on Earth or ~1/14,000th that of Jupiter.

      As Io is gravitationally locked (it’s day is exactly as long as it takes it to complete an orbit round Jupiter), it is only because of orbital resonnance with Europa and Ganymede that Io’s orbit remains slightly eccentric, meaning the gravitational pull of Jupiter varies enough to cook its interior.

  5. Relativity…

    From Anchorage Alaska, to Yap Island, is about 10,000 km of subducting plate. Oceanic seafloor is about 10 to 20 km thick, lets say 15 km for the S&G aspect of it.

    Along this section of subducting plate, the portion that has already gone under reaches as far as 500 km. For the sake of argument, lets say it’s 250 km.

    As a density of 2700 kg/m³, how much do you think that subsided plate has in mass?

    If you guessed 1.0125 x 10^17 kg, you would be right. Not that it’s an accurate number, but that’s the scale of the forces at work.

    Under one of the most accepted mechanical ideas of what drives plate motion, it that of “slab pull.” That enormous mass of the subducted plate, tugs on the rest of the plate and drives melt formation at the spreading centers… though (wait for it)… decompression melting. That melt then makes it’s way up into the slowly opening rift and makes new sea-floor, and adds a bit of shove to the slowly retreating plate.

    Now think about that mass for a minute.

    If the Moon or Sun provides a slight difference in the amount of force applied to one end of the plate, as opposed to another…

    Do you really think it’s going to matter that much given the sheer size of the forces at work?

    Maybe… but it’s not gonna be very much, if at all.

    • I know in the cold light of the day, impossible, but…
      on the other hand, when there are quakes at Macquarie Island there seem to be some kind of a trigger and around the Fiji islands those are usually deep ones, there are on boundaries and seem to get things moving.
      A question for you, My Ruapehu has EQ to the left of the pic and so does Mt Taranaki, the subduction line is to the east of it, any bearing on magma chambers, or is there possibility of new cones etc.

      • Hi Ursh, re Ruapheu almost definitely not, with Taranaki I am not so sure. It is anyway a bit of an oddball. If you look at the axis of the eroded peaks to the north and Fanthams peak, the latest satellite cone on the SE of the mountain, you can see the line is way out of kilt. In the big picture, Taranaki is on a line that extends all the way from the Colville Ridge ( down through Mayor Island and a row of extinct volcano edifices in the Western Waikato.
        The problem is that this line doesn’t match the line of vents at Taranaki, even though Taranaki itself is on the line. I still haven’t worked out why Taranaki is there. Best guess: a subducted microplate? Or is there a whole pile of underplate melt from the back-arc scenario that heats up the overlying crust on this line? I dunno. It seems to be related to the southwards march of the subduction zone but it’s a good hundred miles behind the volcanic arc formed by Ruapehu, Tongariro etc. Interesting beast.

        But to put the quakes in perspective, check out the 60 day charts at Geonet:

  6. The lady doth protest too much, methinks. (Shakespeare Hamlet Act 3, scene 2, 222–230)
    I fear there is a conspiracy afoot. Etna protesting against the troubled Euro and has withdrawn her favours for Europeans. She performs only when most Europeans, like myself are ashleep. Baaaaaaah!

    @ Bruce Stout. Many thanks for the excellent lesson on magma “Chambers”. It was very good and helped me to draw together many bits of acquired knowledge into a logical concept. I look forward to more from you.

    This morning it is not raining. I have no excuse not to go and finish digging the last major bed in readiness for the sowing of beets, carrots, and assorted beans next week. (First week in May…it’s weeks behind the South of England sowing dates here! Also the moon will be waxing so essential to sow seeds then…very old UK tradition amongst arable farmers. )

    Please do not mention to the Volcanic Gods of Iceland that I am not available… they tend to wait until my back is turned before doing anything interesting!!!.

    <<<<<<<Potters off muttering in a paranoid manner.

  7. There has been a 4.7mg near the Maderia islands it seems a lot tof areas seem to be coming to life .

    mb 4.7 Region MADEIRA ISLANDS, PORTUGAL REGION Date time 2012-04-24 04:38:28.0 UTC
    Location 32.42 N ; 16.52 W Depth 37 km Distances 840 km W

    • And that would be MAR for you. A normal day in the spreading of Eurasia and the Vespuccian continents.

        • There is always a lot of earthquakes in the area. They area after all start at the Antarctica and run all the way up to the Arctic.
          The quakes and quakes swarms comes, goes, and moves around, but they are always there somewhere along the MAR. This is how the earth is being remodeled.

          • Also these shown herea are quakes which happened in a time span of 4 weeks, that is a lot of time. You have this number of quakes as shown here around the Iberean peninsula often in 2 days around Iceland. 🙂

        • I don’t know whether or not there have been more EQs than usual in that area because I have not followed it. But I have seen the area mentioned a few times on EMSC.

          Do you have any more information or a specific reason for your concern?

          • I just thought since the movements around El Hierro started there seems to be a lot more of other movements happening around the Azores Portugal and Maderia and even Spain.
            The same in the Pacific it seems to be happening since the Japan earthquake the whole area seems to have become more active and has always looked to me as some form of trigger movement may have been started .

            Although I may be completely wrong .

  8. GeoLurking,

    Why not take all the quake data and stick it through an FFT and see if there is any noticable peaks? Either quake count or power/energy. The FFT function you use in you software will probably pad out the data with zero data upto the next highest power of 2, so it may be best if you cut out the data that is above the highest power of 2 that is less than your total days of data, if that makes sense! Which is probably 8192 days….(around 22 years of data which should be enough!)

    We can work out what the axis mean later if there are any peaks in the output…..

    • Heh… been here before. But, it’s worth a revisit.

      What shows up is not clear enough the be a bona fide signal.

      In order to run this, I set all events in a steadily increasing time axis by days.

      Day 0.000 = 1973-01-01 01:55:28
      Day 14036.975 = 2011-06-08 01:18:53

      And plotted the quake energy. As you can see, nothing stands up and waves at you. There are some oscillatory effects, but that is most likely an artifact of the processing.

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