The sun as a significant agent provoking earthquakes

Abstract

In this paper we provide significant evidence that the sun is a principal agent provoking seismic activity. In particular the aim of the studies presented is to examine the possible relation of the coronal hole (CH) driven high speed solar wind streams (HSSs) with seismicity We performed several statistical studies of solar space and seismological data between 1980 and 2017 as well as a study for a long time interval from the year 1900 until the year 2017. (A1) Concerning the period 1980–2017 among other results we found that the earthquakes (EQs) with M ≥ 83 between 2010–2017 (including the catastrophic earthquakes of Japan 2011 (M91) Sumatra 2012 (M86) and Chile 2015 (M83)) occurred during times of large coronal holes as seen by the Solar Dynamics Observatory (SDO) satellite and were related with CH-driven HSSs observed by the ACE spacecraft several weeks or a few months before the EQ occurrences. (A2) Further research on the hypothesis of the possible HSS-EQ relationship revealed a surprising novel finding: a power spectrum analysis suggests that during the decay phase of the SCC22 and SC23 and at the maximum of SC23 the values of the global seismic (M ≥ 6) energy output shows a periodic variation of ~27 days, which is the mean rotational period of the Sun. (A3) Moderate (not strong) storms in general precede the great EQs. (B) The study of the data for the time interval 1900–2017 revealed that: (1) all of the giant (M ≥ 85) EQs occurred during the decay minimum and the rising phase of the solar cycle or in the maximum phase but at times of a strong reduction of the monthly averaged sunspot number: Chile M95 1960 EQ – Alaska M92 1964 EQ – Sumatra M91 2004 EQ (decay phase) Japan M91 2011 EQ (rising phase of the "strange" SC24) (2) the global energy release of all EQs with magnitudes M ≥ 55 show the highest values during the decay phase of the solar cycle and in particular three years after the solar maximum and (3) a very significant negative correlation (rS = −042p < 10−4) was found between the SSN and the number of earthquakes with M ≥ 7 during the period 1930–2010 during times of moderate and high amplitude solar cycles. (C) Another result of our study is that the comparison of the yearly numbers of great (M ≥ 7) EQs with the SSN fails to provide correct statistical results whereas this is possible for the global seismic energy or the giant EQs. (D) Finally we infer that the case and statistical studies presented in this paper strongly suggest a close relation between CH-associated HSSs and seismic activity. We present some observational evidence that most probably Alfvèn waves mediate the interaction of CH-driven HSSs with seismicity.

Global Earthquake Forecasting System (GEFS): The challenges ahead

“…(14) Anagnostopoulos et al [67] investigate the correlation between solar activity and large-to-great earthquake occurrences over several solar cycles. They test the hypothesis of the electromagnetic coupling of the solar wind with the earthquake occurrence and search for the preferential conditions of such a physical relation (see the short reviews by [12,67] for the various triggering mechanisms proposed for this coupling).…”

“…(14) Anagnostopoulos et al [67] investigate the correlation between solar activity and large-to-great earthquake occurrences over several solar cycles. They test the hypothesis of the electromagnetic coupling of the solar wind with the earthquake occurrence and search for the preferential conditions of such a physical relation (see the short reviews by [12,67] for the various triggering mechanisms proposed for this coupling). Their analysis yields a negative correlation between the sunspot number and M7.8+ earthquakes, shown to be significant compared to a test on a randomized set of earthquakes, during solar cycles SC21-SC24 (1980-2018).…”

“…An alternative approach could consist in first applying the protocol of the null hypothesis of no interaction, as proposed by [12], and demonstrate from there how the use of different data and/or methods may reject the null hypothesis. Anagnostopoulos et al [67] discuss in depth the potential physical mechanisms, which should be further explored in the future in parallel to new statistical tests.…”

“…Yan et al [53] compared the DEMETER data to ground station data and observed some synchronicity, which could help in the future to combine multi-source data to potentially obtain more robust signals, as recommended by Qin et al [56] and Zhuang et al [54], in the GEFS spirit. In other ground-based and satellite-based cases [56][57][58]61,[63][64][65][66][67], since no systematic exploration was done and/or no test on independent data was performed, one cannot infer whether non-seismic precursors exist or are just random fluctuations that seem to be significant as a result of some data selection bias and some kind of over-fitting. Moreover, despite the many graphs of data provided, quantitative analyses remain rare.…”

“…Importantly, the GEFS is initiating a new and much needed phase of cross-disciplinary collaboration [8,50]. The signals addressed in the GEFS issue include: ground-based geoelectric and magnetic anomalies [51][52][53][54][55], radon activity [56], thermal infrared anomalies [57][58][59][60] and longwave radiation [57], combined thermal and gas anomalies [61], (sub)ionospheric signals [53,62,63], total electron content [57], groundwater changes [56,64], precipitation [65], low-frequency "stress waves" [66], solar activity coupling [67], as well as combinations of various signals due to lithosphere-atmosphere-ionosphere coupling [56,57] and comparisons of non-seismic signals to seismic precursors [54,68]. The introductory article of this volume [69] provides a review of the solid-state processes that are proposed to form the basis of the non-seismic precursors and others (in the same volume [70]).…”