Cosmic Rays & Earthquakes
© PITRIS/GETTYA stock photo shows a concept of cosmic radiation. Scientists have found a link between cosmic radiation and earthquakes.
I came across an article with a provocative headline, "Scientists Link Cosmic Radiation to Earthquakes for the First Time".

So I went to look at the underlying study, Observation of large scale precursor correlations between cosmic rays and earthquakes with a periodicity similar to the solar cycle by P. Homola and 43 others.

Hmmm, sez I. Willis's Rule of Authors says that the strength of a scientific study is inversely proportional to the number of authors ... but I digress. The Abstract says:
The search for correlations between secondary cosmic ray detection rates and seismic effects has long been a subject of investigation motivated by the hope of identifying a new precursor type that could feed a global early warning system against earthquakes.

Here we show for the first time that the average variation of the cosmic ray detection rates correlates with the global seismic activity to be observed with a time lag of approximately two weeks, and that the significance of the effect varies with a periodicity resembling the undecenal solar cycle, with a shift in phase of around three years, exceeding 6 ฯƒ at local maxima.

The precursor characteristics of the observed correlations point to a pioneer perspective of an early warning system against earthquakes.
The study says:
Here we report on an observation of the correlations between variation of the average rates of secondary cosmic ray fluxes measured locally and global seismic activity, and we also point to the periodicity of these correlations (or their observability) which corresponds to sunspot number observations back to the 1960s.
They describe their method as:
... an alternative, novel approach on which we report here: comparing the absolute average variabilities of secondary cosmic radiation to the average global sum of earthquake magnitudes.
And their conclusion was:
We have demonstrated for the first time that the variation of the absolute average detection rates of secondary cosmic radiation correlates with the global seismic situation (sum of the magnitudes of earthquakes with magnitudes greater-than or equal to 4, occurring at all locations) that takes place approximately two weeks later than the relevant cosmic ray data. The size of the shift in time between the cosmic and seismic data sets reveals the precursor character of the correlation effect.
So to see if this made sense, I went and got the data for earthquakes, cosmic rays, and sunspots. You can't do a CEEMD or a Fourier analysis unless the data is regularly spaced in time or space, which earthquake data isn't. So I used a variation of Fourier analysis that I invented a few years back, only to find out that I wasn't the first to invent it. Tamino informed me that "The method you describe is very clever. It's also known (in the astronomical literature at least) as the Date-Compensated Discrete Fourier Transform, or DCDFT (Ferraz-Mello, S. 1981, Astron. J., 86, 619)." Fair enough, it proves that I understand Fourier transforms ... the main advantage of the method is that it doesn't require that the data be regularly spaced.

My logic was that if the magnitudes of earthquakes are related to sunspots and cosmic rays as the 44 authors claim, we should see some kind of a significant ~11-year cycle in the earthquake data. Here's the result of my analysis.
Fourier Periodograms
© Watts Up with ThatFigure 1. Fourier Periodograms of monthly sunspots, earthquake average magnitudes, and cosmic rays. The three longest records of cosmic rays are from Thule, Greenland; Jungfraujoch, Switzerland; and Newark, NJ USA. In addition to the earthquakes of magnitude greater than 4 studied by the authors, I also looked at earthquakes of magnitude greater than 7.
From the periodogram, it's obvious that there are no significant cycles in earthquakes at around 11 years. You can see that the cosmic rays are closely connected to sunspots, for well-understood physical reasons.

But there's no such connection between sunspots or cosmic rays and earthquakes.

Does this complete lack of any significant ~11-year cycles in earthquakes show that the 44 authors are wrong?

Nope. Maybe they have discovered the secret sauce for connecting cosmic rays and earthquakes.

But it sure makes their claim much less likely ...

My very best wishes to you all,

w.

PS: Yeah, you've heard it before, you'll hear it again. To cut down the number of misunderstandings, when you comment PLEASE quote the exact words you are discussing.