Guest Post by Willis Eschenbach
Over in the Twitterverse, where I appear as @WEschenbach, in a discussion someone made the following comment:
Solar minimum affects periodicity of volcanic activity.
Year ‘without a summer’, 1816, and several other big volcanos occurred during solar minimum cycles.
I said that wasn’t true, and pointed him to my analysis of volcanoes and sunspots.
Someone else commented:
But interestingly, it is true for earthquakes, for which we have more occurrences. They are less likely at low sunspot numbers, because of less EM tidal force on plates. As spots clime up above ~90, their EM force evidently rises enough to help nudge the plates like moon does.
I thought … “electromagnetic tidal force”?!?
So I decided to take a look. I started by going to the US Geological Survey website to get all of the earthquake records. As is my habit, I first wanted an overview of all of the data. I’ve found through bitter experience that omitting this step can lead to bad outcomes. So I began by plotting up the number of earthquakes per year, shown in Figure 1 below:
Figure 1. Earthquake counts by year, 1900 – 2007
Yikes! You can see why I take an overview of the whole dataset before doing any analysis. Starting in 1964 they got a lot more quakes. I figured that this was an artifact of the detection and recording process, and that there would be many more small quakes in the more recent data. As seen in Figure 2, that turned out to be true.
Figure 2. Annual average earthquake magnitude, 1900 – 2007
Again … yikes.
To get around this, I decided to just look at strong earthquakes, those with a magnitude over 6.5. These were spread out relatively evenly over the whole period, while including smaller magnitude quakes biased the record to more recent times.
To compare these larger earthquakes with sunspots, I first made a “histogram” showing the percentage of days with 1-20 sunspots, 20-40 sunspots, 40-60 sunspots, and so on. This is my baseline. If the earthquakes fall at random with no effect from the sunspots, then the percentage of earthquake days in the histogram “bins” containing e.g. 0-20, 20-40, or 40-60 sunspots should be very close to the baseline histogram of sunspot numbers from all days in the same bins in the period of record. Figure 3 shows that graph.
Figure 3. A histogram of the percentage of daily sunspot numbers on the days when the 3,604 largest earthquakes from 1900 to 2007 occurred (red), compared to the histogram of the percentage of all daily sunspot levels from 1900 to 2007 (blue). The vertical axis shows the percentage of the total number of trials in each bin.
As you can see, the histogram of the sunspots on days when there are earthquakes (vertical red rectangles with red hatching) is very close to the histogram of the sunspots on all days (vertical blue rectangles).
How close are they? Well, we can determine that with a “binomial test”. It gives the 95% confidence interval (95%CI) for the percentage of quakes in each bin. The black/white vertical “whiskers” at the top of each earthquake percentage (red rectangle) show the range that 95% of random trials would fall inside if the earthquake days actually occurred at random.
And as long as the 95%CI overlaps the blue rectangles showing the expected percentage from all the days, we can say that we have no statistically significant evidence that the earthquakes actually are not falling at random. It’s worth noting that some 5% of random earthquakes will fall outside that range … and in fact, in the bin from 120 to 140 sunspots per day, the 95% CI doesn’t quite include the top of the blue rectangle. Finding one or two results like that in a sample this size is not a surprise, as we expect some 5% of random occurrences to be outside the 95% CI.
So there you have it … sunspots do NOT affect earthquakes in any statistically significant fashion. One more interesting conclusion from this—every ten days or so there’s an earthquake stronger than 6.5 somewhere on the planet. Standin’ on shaky ground …
Now in the past I’ve posted up a number of my studies of the purported effects of sunspots on surface weather variables like rainfall, river flows, clouds, sea levels, tides, and the like. There is a list of my investigations here.
And when I began my search, I was a true believer in the solar-weather connections. I’d heard the claim from the British astronomer William Herschel in 1801 that sunspots affected the wheat harvests in the UK. I thought it would be easy to find evidence that sunspots, or some other sunspot-related phenomenon like solar wind or cosmic rays or heliomagnetism or the like, would be affecting some surface weather phenomenon.
But I couldn’t even replicate Hershel’s claims … and neither have other people been able to do so. See here and here for a couple of examples.
Nor, to my great surprise, I have ever been able to find one single surface weather phenomenon which shows the slightest effect from some sunspot-related phenomenon. And today’s study just adds to a long list of failures to find such a correlation.
Now, let’s be clear—it’s very hard to disprove a negative. Finding one black sheep will disprove a positive statement that all sheep are white. But not finding a black sheep doesn’t disprove a negative statement that no sheep are black … maybe you just haven’t looked in the right place.
As a result, I haven’t shown that sunspot-related phenomenon are not affecting some surface weather phenomenon. Maybe I just haven’t looked in the right place. I’d love to actually find something. At this point, it would be a surprise and a coup. All I can say is, I’ve looked at a whole heap of claimed correlations and found nothing.
So to continue my search, let me make the offer that I’ve made several times before. I invite people to send me two links—one to the one very best study that you know of showing a correlation between a sunspot related phenomenon and surface weather of some kind, and a second link to the data used in that study. If you send me those two links I’ll see what I can find, and as my mom used to say, “God willing and the creeks don’t rise”, I’ll report back the results good or bad. A few caveats:
• NO REANALYSIS “DATA”! It’s not data as we commonly understand the term. Instead it’s the output of a computer model … and computer models tend to be linear, with whatever you put in as input coming out as output. Might be lagged and transformed, but what goes in comes out. See my post here for an example. This means that since total solar irradiation is used as an input, it will very likely appear in the output … and that will mean absolutely nothing. So no reanalysis “data”, please.
• I’m asking for two links, one to the study you think is best, and the other to the data used in the study. Without the second link, I cannot even attempt to replicate the study.
• Surface weather-related datasets only, please, no atmospheric datasets. I’m a ham radio operator, H44WE, and I’ve long been aware that changes in sunspot levels are mirrored in changes in the ionosphere. But that’s from about 60 km (37 mi) to 1,000 km (620 mi) altitude, far above us, and those changes don’t seem to make it to the surface.
• Finally, please first check all the posts at the link I gave above to my previous work on sunspots. No good you go to all the trouble of digging out a link to your best study and another one to the data, only to find out that I’ve analyzed it already.
I make this request for links for just the one single best study you know of because the number of bad studies, and in some cases ludicrously bad studies, on this question is huge. So please, don’t send me some laundry list of “27 NEW REALLY AWESOME STUDIES SHOWING IT’S THE SUN, STUPID!” My life is too short to dig through piles of trash looking for a diamond. Send me two links to your best study and data, and time permitting, I’ll take a look.
My very best to everyone on this rainy slow day,
w.
PS: Misunderstandings are the bane of the intarwebs. So I politely request that when you comment you quote the exact words that you are discussing. That way, we can all be clear on exactly what and who you are referring to.
Hi Willis,
https://m.scirp.org/papers/82421
This paper links Kp to earthquakes, but not sunspots. I bring this up because the lack of correlation between sunspots and earthquakes, manifests online as no correlation between solar activity or geomagnetism and earthquakes, (as Harvard Uni’s blog claims). I feel this is a bit of stretch, from sunspots to solar activity.
PS I’m not a scientist, but if you’d like the data on this I’m happy to research.
PSS always great content, thanks.
Willis, if you receive 100 datasets, around 5% will show a nominally significant relationship even if chosen at random. And with datasets that are prescreened for correlations, the number of false positives should increase.
I wish I had the skill to do this kind of analysis, Willis.
If I did, I would investigate the relationship between making toast and finding images of the Virgin Mary on slices of toast.
I think the data on that is far more robust than that of finding images of Jesus on grilled cheese sandwiches, but I am not certain…it could just be an artifact of more people eating toast than making grilled cheese sandwiches.
People are great at spotting patterns.
So good in fact, that we can see them where none exists.
I have no idea about volcanoes and earthquakes and a link to solar activity, but lots of people have reported there is one, and even proposed some mechanisms for how it could be so.
We know what causes earthquakes in a general way: Tectonic plates slide past each other, and get stuck due to irregularities in the rock surfaces. At some point the mechanical strength of the rock that is causing the sticking is exceeded, and the accumulated strain, which had up to that point caused the adjacent rocks to bend, stretch, or just undergo compression, at which point the fault slips suddenly and the resulting motion is what we called an Earthquake.
So presumably at some period of time prior to the earthquake, the rocks that are stuck are very near the breaking point, and might be induced to break free if and when some sort of additional strain or shock can cause a slippage that might have occurred somewhat later without the additional strain or shock.
Or possibly something weakens the rocks a little at that critical juncture.
Looked at in this way, one might expect a huge earthquake in one place, which are known to cause seismic energy waves to ring the whole Earth like a bell, might be expected to cause a flurry of earthquakes in distant locations.
Or like you mention, earth tides might do so…although since they are a constant regular event travelling around the world, they might be expected to simply cancel out with regard to periodicity.
So what is the relative amount of energy that might be delivered to a rock near the breaking point by such things as distant large quakes, tides, current flows through the Earth, cosmic rays that penetrate the ground, etc?
Large earthquakes on one part of the San Andreas fault is known to increase the accumulated strain on adjacent fault sections, but AFAIK, large quakes cause many after shocks as nearby rocks settle into a new equilibrium, and sometimes a large quake is preceded by a foreshock (in fact the only way to tell if a quake is a foreshock or the main event is in retrospect), and sometimes two similar sized quakes can occur in the same area separated by some short interval…hours, days…a week or more…but I know of no tendency for a huge quake in one part of the world to trigger Earthquakes all around the globe.
So…why not? The biggest earthquakes might be supposed to be followed by concentric circles of other quakes…if there are always some number of quakes waiting for some slight triggering event.
The logical conclusion is that the amount of energy needed to trigger a large quake, which presumably was caused by a large jam up allowing a large amount of strain to accumulate, would need a very large triggering event…large in comparison to the strain accumulated by years and years of inches per year of relative plate motion. Decades to centuries of such, judging by the time interval between major quakes.
That is a lot of energy.
And that seems like the reason that faults do not tend to unzip all at once, but instead do so with an often wide and (seemingly anyway) random interval of time in between quakes on adjacent fault segments.
BTW…right now the faults in California are estimated by the USGS to be overdue for a whole bunch of century scale events.
Thanks, Nicholas. Like you, I believed that the sunspot-related changes could affect lots of things. And I was pretty certain that I’d find some relationship between tidal forces and either earthquakes or volcanoes. It just made too much sense that the flexing of the solid earth would have to induce either eruptions or quakes.
Unfortunately, despite all of my looking, I find nothing. And this claim of mid-ocean spreading zone earthquakes causing El Ninos and the like is just more of the same. Let me repeat my graphic from above.
As you can see, this is just another crappy study where they didn’t do their homework and end up getting nonsense peer-reviewed. It’s not a change in spreading-zone quakes. It’s a change in the acquisition and recording of quake data.
Finally, despite my grumping at you, I do appreciate the passion that you have for the subject.
Best regards,
w.
A good summary from quakewatch.net of the possible influence on earthquakes from external magnetic and electrical fields…
https://youtu.be/hWEn5JZ22dk
Mr_Ed, that seems more like a summary of the possible influence on external magnetic and electrical fields from earthquakes … which, given the existence of piezoelectricity, seems at least possible.
w.
I came to the conclusion that the positional relationships had such a small effect that it was irrelevant.
https://www.volcanocafe.org/the-moon-and-the-moonie/
EM tides? If the Sun & Moon tidal effect on Earth is not significant for earthquakes, and barycenter tidal effects of the the other planets can’t influence the sun, the chance of finding a stronger tidal effect is remote.
On the other hand, I enjoy a good mystery, so look at it like this. We can see stars and planets and asteroids, so we can imagine being hit by a giant meteor. Yet the biggest meteor craters we have are mere pimples on the surface of the Earth. They can’t compare to the many mountain ranges, built by past and current seismic activity. One earthquake at a time. And then there are volcano mountains and volcano explosions. The Earth beneath our feet, the deep earth, has a super-sized “weather” system, presumably with huge convection and currents pushing around huge continents and generating a magnetic field. Which could be changing! Or flipping! (that’s for the perennially terrified)
Earthquakes can be detected by seismic instruments. As can nuclear explosions. We could even measure earthquakes in Hiroshimas. One quote from a usgs.gov FAQ: “nuclear explosions typically release energy between 2-50 kilotons of yield, compared to, for example, the M6.5 Afghanistan earthquake in May of 1998 that had an equivalent yield of 2,000 kilotons.” What does that make the “Yellowstone Ticking Bomb”?
If I was interested enough I would look for a correlation between change in Length of Day (Earth rotation speed) and earthquakes (not expecting to find one). Or between climate change and LOD. Anything to get away from the obsession with CO2!
I had an acquaintance that noted anything less that 2 SD above gaussian noise was probably not worth looking at. In the work for the above, nothing came anywhere close to that.
Even 2 SD will give a false positive in 5 % of cases for gaussian distributions, and often more for data that are not normally distributed. If you look at several candidate correlations you are quite likely to find at least one false positive. This practice is known as “P-chasing”.
In physics you would almost certainly not even be able to publish results at that significance level.
Actually large earthquakes have been shown to affect Length of Day (not the other way around).
This is actually inevitable since they definitely move large masses around relative to the Earth’s rotation axis.
Incidentally there is a strong rumour that Freeman Dyson once figured out a way to explode nuclear bombs underground with a negligible seismic transfer of energy, but that it is still secret since it was tested in Nevada and found to work.
Hello Mods,
I posted a comment a while back which went into moderation.
Thanks,
https://www.scirp.org/journal/paperinformation.aspx?paperid=82421
Hi Willis,
I am curious what you think about the above paper by a NASA researcher linking Kp and earthquakes. Is this cow boy science or does the connection to geomagnetic storms pass muster? Would you like me to find the data or are we on sunspots only?
(Sorry if this pops up twice, there was a problem with my word press subs and I dont know if the other will eventually post)
Tom, the Kp index basically tracks with the sunspot cycle. So the analysis showing the lack of correspondence of sunspots and quakes is LIKELY valid for the Kp index as well. However, haven’t done the analysis.
w.
Maybe a misunderstanding, Yes I realized the relationship, but the paper found the link to periods in close proximity to the geomagnetic storms was statistically correlated to earthquakes, (not the amount of sunspots.)
“The statistical significance of nearly 100% is obtained for the Kp variations, synchronizing with more earthquakes in the Pacific Rim region.”
Thanks Tom
Tom, any time anyone claims a “statistical significance of nearly 100%” I start to laugh. In particular, they’ve been very coy about just how they adjusted for autocorrelation in their data, viz:
Riiight … the Hurst Exponent of the Kp Index is 0.87, and when it’s that high, statistical significance becomes extremely elusive. They have some 449 data points in the 28 days preceding and following the quakes. But once adjusted for autocorrelation, the “effective N” is only about 5 data points, not enough to determine anything.
And next, three earthquakes? Three? That’s like rolling the dice three times and declaring that the dice are loaded. Not happening.
Just sayin’ … from what they’ve done, it’s far from established.
w.
Thanks for that Willis,
Great to have someone so scientifically literate to ask.
Tom
The only external factor actually known to affect volcanic eruptions and earthquake activity is the growth and decay of ice sheets.
This has been shown repeatedly for Iceland (mainly volcanoes) and Scandinavia (only earthquakes). Data from other areas are less convincing.
But then it would be rather odd if the disappearance of a couple of kilometers thickness of ice did not affect volcanic and seismic activity.
If large earthquakes are associated with sort term periods of slow solar wind, that could be at any number of sunspots. So this study is meaningless.
Willis,
Thanks for doing the work I am too inept to do. Please understand that my failure to do the homework is not due to laziness, but rather that God gave you gifts I lack.
I will confess I am disappointed. I hope you some day eventually do find a link between sunspots and activity on earth. Perhaps there is a correlation such as fewer sunspots = more comments at WUWT?
I hope you will forgive me for clinging to a bit of trivia: It is my understanding that, around fifteen years after the start of the Dalton Minimum there were two of the largest eruptions of the past 250 years, the Tamboro eruption and, roughly five years earlier, a “mystery eruption” (shown by ash in ice-cores in both Greenland and Antarctica.)
I cling to this trivia because we are approaching roughly fifteen years into the start of current “Quiet Sun”, and the trivia allows me to expect the worst, and enables me to creep about darkly peering up from under an umbrella on sunny days…..which does wonders for my reputation as an old crank.
Interesting place for a massive quake.
Just a few hours ago, a massive 7.7 quake struck in the area between Jamaica and Cuba. Appears to be right on that fault line that runs through there.
Reports of buildings shaking in Miami, but I felt nothing in SW Florida.