Do solar flares cause earthquakes? - The Sun Today with C. Alex Young, Ph.D.
The main proxy that we have of past solar intensity comes from the proven correlation to the number of sunspots, which have been recorded. By comparing the year sunspot cycles and global earthquake events during analyzed to examine the relationship of these values and to understand the. What are sunspots? Sunspots are areas on the photosphere (the visible surface of the sun), which appear darker than the surrounding surface of the sun by.
The occurrence rate of both solar flares in blue and earthquakes in red. For the next plot, I have gathered together data on the appearance of sunspots over the same 30 year period http: By overlaying the occurrence of solar flares on this plot, we can clearly see that the number of flares rises and falls with the number of sunspots the orange curveagain every 11 years or so.
I would call this a pretty strong case for proving that flares are in someway related to sunspots which of course we know they are, as we can see flares occurring in regions of intense magnetic field on the Sun.
The occurrence rate of both solar flares in blue and sunspots in red. Click on Image to See A Larger Version I have also been looking at data on ionospheric disturbances here on earth as part of my own research again, this data is publicly available via the Stanford University website http: I selected a day in which I knew there was significant solar activity in this case, 18 February and plotted the solar activity for that day top panel against the corresponding changes in the upper atmosphere above Austria bottom panel.
This clearly shows that at least five of the flares that day denoted by the vertical dashed red lines had a direct impact on the ionosphere. Again, this suggests a causal relationship between solar activity and atmospheric disturbances; something not seen in the earthquake data. The flare solar activity for 18 February top panel plotted against the corresponding changes in the ionosphere above Austria bottom panel.
But these are large-scale statistical studies.
No link between solar activity and earthquakes
Would that then have any geological effects? Well, what is a solar flare exactly?
So flares are essentially just that; increases in X-ray emission and sometimes gamma-rays. There is, of course, increased emission from across the spectrum: The only solar emission that makes it to the surface is visible light that we can see with our eyes, and radio emission see figure below.
So barely any of this X-ray light makes it through the atmosphere, let alone to beneath the surface to where earthquakes occur. Similarly, CMEs are essentially clouds of charged particles which get deflected by our magnetic field and rarely make it to the surface. This shows the what wavelengths of electromagnetic radiation can penetrate Earth's atmosphere and what wavelengths are stopped by the atmosphere.
Of course, there are more sophisticated data analysis techniques and correlation tracking algorithms available compared to that which I have presented here. So if you feel that my rather simplistic approach has failed to reveal a potential relationship between solar and geological activity, then I urge you to sift through the data for yourself. This is how science works, which is why I have included links to the pages where I obtained my data so you may repeat the experiment for yourself if you choose, in order to verify or refute my conclusions.
But simply noting that a solar flare and an earthquake occurred together within a short time frame does not imply that one caused the other. We continue to be asked by many people throughout the world if earthquakes are on the increase. However, a time lag of five to six years means, as well as negative values, anti-cyclicality, i. The maximum positive correlation coefficient can be found in the comparison of the Sunspot Number with the Earthquake Data from Central Europe, with a value slightly above 0.
A more detailed picture of this particular case is given in Figure 5 b. Furthermore, common periodicity in the magnetic field strength data is found according to Figure 6.
The most prominent feature is an approx. Yet another approach is the comparison between the magnetic field strength and the regional earthquake data. The correlation coefficients for up to 20 years time lag are given below. It shows the highest correlation for the case of Niemegk and Central Europe.
The correlation coefficient is about 0. However, Figure 7 shows that the correlation almost exactly resembles the input values of field strength at Niemegk.
This also means that there is equally high correlation not only for zero, but also for about 18 years time lag, which is difficult to explain. Cointegration As mentioned in Section 3.
Intuitively one already suspects the geomagnetic records to meet the criteria for Figure 6. The red line shows the curve form of the magnetic field strength in Niemegk de-trended. The series follow a random walk secular variations with some degree of individual, random freedom magnetic storms, currents in the ionosphere On the other hand, the Sunspot Number does not show those random walk characteristics, resembling a stationary process with a rather strict periodicity.
Also the earthquake occurrence is stationary, following in a basic model a Poisson Distribution. The test statistics show indeed a cointegration relation between the three magnetic field strength records.
The graph for the Residuals ut in Figure 8 is given by 5 are the records from the observatories, constant factors and c is a constant that shifts the curve to zero mean. Although this is not exactly a valid test, this could mean that Sunspot Number and magnetic field strength in a relation of year-long cycles are independent.
As the earthquake data is linked to the same problem, further cointegration testing is omitted. This fact, however, is expected, given Figure 8. Residuals from the cointegration analysis according to Equation 5.
Do solar flares cause earthquakes?
The Residuals basically show the difference in the three magnetic field strength records, whilst common features are cancelled out.
During solar maxima the number of magnetic storms increases considerably, yet, those are effects, typically in the range of hours to few days. Hence, the long-term magnetic field strength is not expected to be influenced strongly by these disturbances. The cointegration analysis including the Sunspot Number, yields the same result, as the residuals resemble the variations in solar activity. This could mean that there is no direct link between the two values, i.
Does the sun trigger earthquakes?
Although the three geomagnetic observations are cointegrated, the approx. These are non-predictable impulses or inversion of the trend-direction of the declination of the magnetic field . Those variations, that are still not very well understood, have roughly shown that periodicity in the last 50 years. However they include no direct information for this report. Concerning the earthquake data, there also seems to be no strong relation between their occurrence and the solar activity Figure 4.
Taking greater time shifts between the series into account, there is data plotting above the mean random-correlation limit. Tavares and Azevedo , on the other hand, state a positive result in their study regarding the connection between the solar cycles and the earthquake activity. Positive in the sense of a existing relationship and in the sense of higher earthquake activity during solar maxima.
Firstly, they examine historic events, that coincide with the Maunder and the Dalton minima. They find an overall lower number of events during those two periods, though the activity in tectonic regions of mostly strike-slip faults is slightly increased. Tavares and Azevedo  propose that high solar activity could compress the magnetic field, exerting a pressure on certain tectonic settings, whereas during a minimum, the energy is liberated in zones characterized by strike-slip faulting or subduction zones.
Their observations are backed by observations during the last 50 years, similar to this study. The last maximum aroundearthquakes seem to have occurred more frequently on different tectonic plates. This result, however, is not universal for all parts of the earth and not during all of the 5 maxima between and Their observations during the modern period seems exclusively based on graphical comparison and not one number is shown in this part.
Also, the comparison of occurrence during the two historic minima vs. Those effects could probably as well be explained by natural random behaviour. The results of this work rather contradict the observations from Tavares and Azevedo , as the data presented in this article generally shows no or anti-cyclic correlation. Yet it is interesting that—though not predominant—they also describe in their work an inverted relationship between seismicity and solar activity.
As such events happen considerably more frequently during solar Sunspot Maxima, it is of interest, whether earthquake occurrence resembles these cycles. This study doubts the results presented by Tavares and Azevedo , as the only clear signs of correlation found, predict a negative correlation between earthquakes and solar activity. Yet, future studies could come to more significant conclusions, by, for example, correlating directly CME events with earthquakes.
In any case, it is important to take the complexity of an earthquake process into consideration, as there are many factors influencing the behaviour of fault zones and if at all, solar activity represents only one part of the puzzle. Thus, effects are presumably small, so all the more there is need for robust statistical methods.
Otherwise, this topic stays in its niche, widely ignored by the scientific community. Natural Science, 3, Earth and Planetary Science Letters, 3, Science in China Series G: