EGU General Assembly 2014, held 27April - 02May, 2014 in Vienna, Austria


Session : PS2.6 - Volcanism, tectonics, impacts and other geological processes across the Solar System

Geological processes such as volcanism, tectonics, and impacts are fundamental to the formation and evolution of the planets, moons, asteroids and comets of our Solar System. These processes are the primary agents responsible for the shaping of planetary surfaces, each of them in different ways and at different rates. For example, asteroids and comets have played a critical role during planetary evolution, by delivering the primary constituents of planetary bodies and by promoting resurfacing via impacts. Volcanic and tectonic processes are efficient mechanisms to reshape planetary surfaces and provide valuable information about planetary interiors and evolution. The study of geological processes in the Solar System is at the crossroad of many scientific disciplines using either in-situ sampling and analysis, remotely sensed data, or experimental and numerical modelling.

This session aims to compile all facets of volcanism, tectonism, impact cratering, and their associated interactions with other geological processes observed in our Solar System. By providing a forum for a broad range of discussions, these observations and interpretations will be investigated and (re)viewed in the light of our current understanding of related processes on Earth. Comparative studies on volcanic/tectonic systems, impact structures, and other processes on Earth using multi-instrumental, remotely sensed, experimental, computational, or field data are particularly welcome.


Significant statistically relationship between the great volcanic eruptions and the count of sunspots from 1610 to the present

Casati, Michele



The assertion that solar activity may play a significant role in the trigger of large volcanic eruptions is, and has been discussed by many geophysicists. Numerous scientific papers have established a possible correlation between these events and the electromagnetic coupling between the Earth and the Sun, but none of them has been able to highlight a possible statistically significant relationship between large volcanic eruptions and any of the series, such as geomagnetic activity, solar wind, sunspots number.


In our research, we compare the 148 volcanic eruptions with index VEI4, the major 37 historical volcanic eruptions equal to or greater than index VEI5, recorded from 1610 to 2012 , with its sunspots number.
Staring, as the threshold value, a monthly sunspot number of 46 (recorded during the great eruption of Krakatoa VEI6 historical index, August 1883), we note some possible relationships and conduct a statistical test.

• Of the historical 31 large volcanic eruptions with index VEI5+, recorded between 1610 and 1955, 29 of these were recorded when the SSN<46. The remaining 2 eruptions were not recorded when the SSN<46, but rather during solar maxima of the solar cycle of the year 1739 and in the solar cycle No. 14 (Shikotsu eruption of 1739 and Ksudach 1907) (chart 1).

• Of the historical 8 large volcanic eruptions with index VEI6+, recorded from 1610 to the present, 7 of these were recorded with SSN<46 and more specifically, within the three large solar minima known : Maunder (1645-1710), Dalton (1790-1830) and during the solar minimums occurred between 1880 and 1920. As the only exception, we note the eruption of Pinatubo of June 1991, recorded in the solar maximum of cycle 22 (chart 2).

• Of the historical 6 major volcanic eruptions with index VEI5+, recorded after 1955, 5 of these were not recorded during periods of low solar activity, but rather during solar maxima, of the cycles 19,21 and 22.

The significant tests, conducted with the chi-square χ ² = 7,782, detect a p-value equal to 0,005. Applying a correction of Yates, p-value assume the value of 0,009.

We affirm therefore that the occurrence of a major volcanic eruption, greater or equal to VEI4 index, during the weak solar cycles, is statistically significant and justifies the hypothesis of large volcanic eruptions in the next decade, with reference not only to the weakness of the current solar cycle SC24, but the probable entrance, in a long and deep solar minimum, during the transition to the next solar cycle SC25. Assumption formulated by many solar physicists.[Ahluwalia,2013][Goelzer;Smith;Schwadron;McCracken,2013][Livingston;Penn;Svalgaard,2012][Steinhilber;Beer,2013]

The list of the major historical eruptions are extracted from the Smithsonian Institute (Global Volcanism Program). The sunspots number is extracted from the Belgium Solar Influences Data Analysis Center (SIDC).

(*)  Relative sunspots number  Data : Group SSN yearly from 1610 to 1699; SSN yearly "SIDC" from 1700 to 1748; SSN monthly "SIDC" from 1749 to present.

(*1)  Jihong Cole-Dai, David Ferris, Alyson Lanciki, Joël Savarino, Mélanie Baroni,  Mark H. Thiemens Cold decade (AD 1810–1819) caused by Tambora (1815) and another (1809) stratospheric volcanic eruption Geophysical Research Letters Volume 36, Issue 22, November 2009 doi: 10.1029/2009GL040882

The yellow area represent  the period from 1610 to the present and includes 30 of the 37 volcanic eruptions equal to or greater than VEI5 index.

Seven of the eight major volcanic eruptions equal to or greater than VEI6 index have occurred during  three well-known historical periods: Maunder, Dalton and the period of solar minimum occurred from 1880 to 1920. All these periods are characterized by a very low solar electromagnetic activity.


It is possible to observe a relationship between large earthquakes with a magnitude of M8.3+ and the well-known two periods included in the eleven-year cycle of the solar magnetic activity: solar minimum and solar maximum (Chart 3). However, this analysis did not show any statistically significant relationship.

The list of 29 events of magnitude M8.3 + occurred since 1900 is extracted by the U.S. Geological Survey.
Of the 29 earthquakes of magnitude M8.3 + :

• 17 have occurred when the SSN (monthly) < 46;
• 9 have occurred in the years of solar maximum, cycles 14, 15, 17, 23 and 24;
• 3 have not occurred during the years of solar minimum or maximum.





1. Abdurakhmanov, A. I., P. P. Firstov, and V.A. Shirokov, A possible link between volcanic eruptions and the 11-year cycle of solar activity (in Russian), Byul. Vulkanol. Stants., 52, 3-10, 1976

2. Ahluwalia H.S., An empirical approach to predicting the key parameters for a sunspot number cycle University of New Mexico, Department of Physics & Astronomy, MSC07 4220, Albuquerque, NM 87131, USA An empirical approach to predicting the key parameters for a sunspot number cycle doi:10.1016/j.asr.2013.11.044

3. Casati Michele, Straser Valentino ; Possible relationship between changes in IMF, M7+ earthquakes and VEI index, during the transition between the solar minimum cycle 23 and the rise of solar cycle 24 EGU General Assembly 2013, held 7-12 April, 2013 in Vienna, Austria, id. EGU2013-1405

4. Casey John L. – 2010 ; Correlation of Solar Activity Minimums and Large Magnitude Geophysical Events

5. Charvátová I. Long-term relations between the solar inertial motion (SIM) and solar, geomagnetic, volcanic activities and climate : AGU Foz do Iguaçu Brazil 2010

6. Duma G. and G. Vilardo (1998),  Seismicity cycles in the Mt.Vesuvius area and their relation to solar flux and the variations of the Earth’s magnetic field. Phys. Chem. Earth, 23 (9-10), 927-931. doi:10.1016/S0079-1946(98)00121-9

7. Friedhelm Steinhilber, Jürg Beer, Prediction of solar activity for the next 500 years Journal of Geophysical Research: Space Physics Volume 118, Issue 5, pages 1861–1867, May 2013 doi:10.1002/jgra.50210

8. Goelzer, Smith, Schwadron, McCracken An analysis of heliospheric magnetic field flux based on sunspot number from 1749 to today and prediction for the coming solar minimum Journal of geophysical research: space physics, vol. 118, 7525–7531, doi:10.1002/2013ja019404, 2013

9. Livingston, W., Penn, M. J.,Svalgaard, L. Decreasing Sunspot Magnetic Fields Explain Unique 10.7 cm Radio Flux The Astrophysical Journal Letters, Volume 757, Issue 1, article id. L8, 4 pp. (2012) doi:10.1088/2041-8205/757/1/L8

10. Jaggar, T. A., Volcanic cycles and sunspots, Volcano Lett., 326, 1-3, 1931.

11. Jensen, H. I., Possible relation between sunspot minima and volcanic eruptions, J. R. Soc. N. S. W., 36, 42-60, 1902

12. Jensen, H. I., Possible relation between sunspots and volcanic and seismic phenomena and climate, J. R. Soc. N. S. W., 38, 40-90, 1904.

13. Jihong Cole-Dai, David Ferris, Alyson Lanciki, Joël Savarino, Mélanie Baroni,Mark H. Thiemens  Cold decade (AD 1810–1819) caused by Tambora (1815) and another (1809) stratospheric volcanic eruption Geophysical Research Letters Volume 36, Issue 22, November 2009 doi: 10.1029/2009GL040882

14. Lyons, C. J., Sunspots and Hawaiian eruptions, Mort. Weather Rev., 27, 144, 1899

15. Madonia, P.; Gurrieri, S.; Inguaggiato, S.; Giugliano, P.; Romano, P.; Spadaro, D.; Zuccarello, F Atmospheric Pressure Anomalies Recorded on Italian Volcanoes: Possible Relationships With Solar Activity American Geophysical Union, Fall Meeting 2005, abstract #A43C-0118 2005AGUFM.A43C0118M

16. Mazzarella, A.; Palumbo, A. Does the solar cycle modulate seismic and volcanic activity? J. Volcanol. Geotherm. Res., 1989, Vol. 39, No. 1, p. 89 – 93 doi :10.1016/0377-0273(89)90023-1

17. O'Reilly, J.P., On the dates of volcanic eruptions and their concordance with the sunspot period, Proc. R. Irish Acad., 5, 392-432, 1899

18. Střeštik, J. Possible correlation between solar and volcanic activity in a long-term scale Solar variability as an input to the Earth's environment. International Solar Cycle Studies (ISCS) Symposium, 23 - 28 June 2003, Tatranská Lomnica, Slovak Republic. Ed.: A. Wilson. ESA SP-535, Noordwijk: ESA Publications Division, ISBN 92-9092-845-X, 2003, p. 393 – 396

19. Sytinsky A.D. About planetary atmospheric perturbations during the strong earthquakes. //Geomagnetism and Aeronomy, v. 37, 1997, p. 132-137

20. Stothers Richard B. Volcanic eruptions and solar activity Journal of Geophysical Research: Solid Earth (1978–2012) Volume 94, Issue B12, pages 17371–17381, 10 December 1989 doi: 10.1029/JB094iB12p17371

21. Vinayak G. Kolvankar Sun induces semi-diurnal stress on the earth surface's, which trigger earthquakes and volcanic eruptions - 2008   New Concepts in Global Tectonics Newsletter, no.47, June, 2008 Seismology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India