On the correlation between solar activity and large earthquakes worldwide

Abstract

Large earthquakes occurring worldwide have long been recognized to be non Poisson distributed, so involving some large scale correlation mechanism, which could be internal or external to the Earth. Till now, no statistically significant correlation of the global seismicity with one of the possible mechanisms has been demonstrated yet. In this paper, we analyze 20 years of proton density and velocity data, as recorded by the SOHO satellite, and the worldwide seismicity in the corresponding period, as reported by the ISC-GEM catalogue. We found clear correlation between proton density and the occurrence of large earthquakes (M > 5.6), with a time shift of one day. The significance of such correlation is very high, with probability to be wrong lower than 10-5. the correlation increases with the magnitude threshold of the seismic catalogue. A tentative model explaining such a correlation is also proposed, in terms of the reverse piezoelectric effect induced by the applied electric field related to the proton density. This result opens new perspectives in seismological interpretations, as well as in earthquake forecast. Worldwide seismicity does not follow a Poisson distribution 1 , not even locally 2. Many authors have proposed specific statistical distributions to describe such a non-poissonian behavior 3-7 but none of these is really satisfactory, probably because the underlying physical process has not been really understood. Many authors have hypothesized that a tidal component may show up in earthquake activity (e.g. 8,9) but generalized evidence has never been proven. Quite recently, some authors 10 suggested that earthquake occurrence might be linked to earth rotation speed variations. There is also a smaller number of researchers that studied possible links among solar activity, electromagnetic storms and earthquakes (e.g. 11-16). The first idea that sunspots could influence the earthquake occurrence dates back 1853, and is due to the great solar astronomer Wolf 17. Since then, a number of scientists has reported some kind of relationship between solar activity and earthquake occurrence 16,18,19 ; or among global seismicity and geomagnetic variation 15,20 or magnetic storms 21,22. Also, some mechanisms have been proposed to justify such correlations: small changes induced by Sun-Earth coupling in the Earth's rotation speed 23 ; eddy electric currents induced in faults, heating them and reducing shear strength 24 ; or piezoelectric increase in fault stress caused by induced currents 25. However, none of these studies allowed achieving a statistically significant conclusion about the likelihood of such mechanisms. On the contrary, 26 argued that there is no convincing argument, statistically grounded, demonstrating solar-terrestrial interaction favoring earthquake occurrence. However, the large interest nowadays for possible interactions between earthquake occurrence and extra-terrestrial (mainly solar) activity, is testified for instance by the Project CSES-LIMADOU, a Chinese-Italian cooperation aimed to launc...

The Analytical Contribution to the Theory of Solar-induced Earthquakes: the Croatian December 2020 M=6.4 Case Study

“…The magnitude of the elaborated earthquake ts within threshold of M>5.6 as used in [13]. The results of PD analysis strongly agree with their ndings, which strengthens positive associations found in the respective research.…”

“…Here, the PD time-series before major earthquake (M=6.4) at the end of 2020 in Croatia were examined. The ndings agree with previous work published in [13], as well as other previously mentioned researches. The increase in PD values has been found within one day before the major earthquake strike.…”

“…In the recent results [13], 20 years of solar PD and velocity data as recorded by the SOHO mission were analyzed together with the worldwide seismicity in the corresponding period. Here, the relationship of major earthquakes and changes in density of incoming solar particles was investigated.…”

A Statistical Study of the Correlation between Geomagnetic Storms and M ≥ 7.0 Global Earthquakes during 1957–2020

“…So far, researchers have proposed several mechanisms about Lithosphere-Atmosphere-Ionosphere (LAI) coupling during the preparation process of earthquakes [40,41]. For example, Vito Marchitelli et al analyzed the correlation between 20-year proton density and large earthquakes worldwide and argued that such a relationship could be explained with a reverse piezoelectric effect [28]. According to previous studies [42], large electric currents could generate stress changes in rocks.…”

“…Most studies focus on the seismo-electromagnetic phenomena generated by underground activities before earthquakes or the perturbations in the atmosphere and the ionosphere, especially the ultra-low-frequency electromagnetic phenomena [14][15][16] and GPS total electron content changes [17][18][19]. In addition, some researchers studied the possible links among earthquakes, solar activity, and geomagnetic storms, and they revealed the seismicity of the earth may be related to the solar activity [20][21][22][23][24][25][26][27][28][29]. For instance, the earthquakes tend to occur in greater numbers during the sunspot maximum and the descending phase of the solar cycle [23,25].…”