On the correlation between solar
\nactivity and large earthquakes
\nworldwide

Large earthquakes occurring worldwide have long been recognized to be non Poisson distributed,
\nso involving some large scale correlation mechanism, which could be internal or external to the
\nEarth. Till now, no statistically significant correlation of the global seismicity with one of the possible
\nmechanisms has been demonstrated yet. In this paper, we analyze 20 years of proton density and
\nvelocity data, as recorded by the SOHO satellite, and the worldwide seismicity in the corresponding
\nperiod, as reported by the ISC-GEM catalogue. We found clear correlation between proton density
\nand the occurrence of large earthquakes (M > 5.6), with a time shift of one day. The significance of such
\ncorrelation is very high, with probability to be wrong lower than ­10 –5 . The correlation increases with
\nthe magnitude threshold of the seismic catalogue. A tentative model explaining such a correlation is
\nalso proposed, in terms of the reverse piezoelectric effect induced by the applied electric field related
\nto the proton density. This result opens new perspectives in seismological interpretations, as well as in
\nearthquake forecast.