مجله ژئوفیزیک ایران

مجله ژئوفیزیک ایران

Investigation of temporal changes of seismicity and magnetic parameters before earthquakes with a magnitude of around 6 in Iran in 2017

مقالات آماده انتشار

نوع مقاله : مقاله پژوهشی‌

نویسندگان
Pooyan Hasan Beygi 1
Ali Moradi 2
Mohammad Javad Kalaee 3
1 M.Sc., Institute of Geophysics, University of Tehran, Tehran, Iran
2 Associate Professor, Institute of Geophysics, University of Tehran, Tehran, Iran
3 Associate Professor, Institute of Geophysics, University of Tehran, Tehran, Iran Associate Professor, Department of physics education, Farhangian University, Tehran, Iran
10.30499/ijg.2026.435424.1567
چکیده
This study examines temporal changes in seismicity and solar-geomagnetic parameters prior to moderate-to-large earthquakes in Iran during 2017-2018, with emphasis on the evolution of the Gutenberg-Richter b-value as a potential indicator of changing seismic regime. We selected five significant earthquakes for detailed analysis. While the study primarily focuses on main shocks with magnitudes around 6, the 2017 M 5.2 Malard (Tehran) earthquake was specifically included due to its proximity to the capital, affecting a population of over 10 million, and its status as the most significant instrumental event near Tehran in recent decades. Declustered earthquake catalogs from the Iranian Seismological Center (IRSC) were used to track b-value variations, while external parameters - including Earth’s magnetic field strength, solar wind proton density, geomagnetic indices including Disturbance Storm Time (Dst) and planetary K index (Kp), sunspot number, and 10.7 cm solar radio flux (F10.7 index) concerning fluctuations in b-value preceding major earthquakes - were analyzed at daily, hourly and 27‑day resolutions. In four out of five cases, the b-value showed a pronounced decrease within several weeks before the mainshock, indicating a temporary shift toward the dominance of larger-magnitude events, consistent with stress concentration patterns observed in prior studies. Four mainshocks also occurred when sunspot numbers and the F10.7 index were near their minimum values over the study period, whereas 27‑day averaged proton density tended to be relatively high close to the occurrence times. Moreover, the Kp index displayed low 27‑day averages for four events, and Dst and Kp indices showed localized anomalies within ±48 hours of some mainshocks. These patterns suggest possible temporal associations between seismic and solar-geomagnetic variability at monthly timescales, although no formal statistical tests were applied. However, the small number of events, uncertainties in the seismic and magnetic datasets and the absence of formal statistical testing limit the strength of any conclusions and preclude causal inference. The correlations identified here should therefore be regarded as preliminary and do not imply that solar or geomagnetic activity directly triggers earthquakes; rather, they suggest that solar-magnetic parameters may offer complementary contextual information on the evolving state of the crust when used alongside conventional seismotectonic indicators, motivating further studies with larger datasets and more rigorous statistical and physical modeling frameworks.
کلیدواژه‌ها
Earthquake precursor
seismic b-value
magnetic storms
solar proton
solar activity

موضوعات

عنوان مقاله English

Investigation of temporal changes of seismicity and magnetic parameters before earthquakes with a magnitude of around 6 in Iran in 2017

نویسندگان English

Pooyan Hasan Beygi 1
Ali Moradi 2
Mohammad Javad Kalaee 3
1 M.Sc., Institute of Geophysics, University of Tehran, Tehran, Iran
2 Associate Professor, Institute of Geophysics, University of Tehran, Tehran, Iran
3 Associate Professor, Institute of Geophysics, University of Tehran, Tehran, Iran Associate Professor, Department of physics education, Farhangian University, Tehran, Iran
چکیده English

This study examines temporal changes in seismicity and solar-geomagnetic parameters prior to moderate-to-large earthquakes in Iran during 2017-2018, with emphasis on the evolution of the Gutenberg-Richter b-value as a potential indicator of changing seismic regime. We selected five significant earthquakes for detailed analysis. While the study primarily focuses on main shocks with magnitudes around 6, the 2017 M 5.2 Malard (Tehran) earthquake was specifically included due to its proximity to the capital, affecting a population of over 10 million, and its status as the most significant instrumental event near Tehran in recent decades. Declustered earthquake catalogs from the Iranian Seismological Center (IRSC) were used to track b-value variations, while external parameters - including Earth’s magnetic field strength, solar wind proton density, geomagnetic indices including Disturbance Storm Time (Dst) and planetary K index (Kp), sunspot number, and 10.7 cm solar radio flux (F10.7 index) concerning fluctuations in b-value preceding major earthquakes - were analyzed at daily, hourly and 27‑day resolutions. In four out of five cases, the b-value showed a pronounced decrease within several weeks before the mainshock, indicating a temporary shift toward the dominance of larger-magnitude events, consistent with stress concentration patterns observed in prior studies. Four mainshocks also occurred when sunspot numbers and the F10.7 index were near their minimum values over the study period, whereas 27‑day averaged proton density tended to be relatively high close to the occurrence times. Moreover, the Kp index displayed low 27‑day averages for four events, and Dst and Kp indices showed localized anomalies within ±48 hours of some mainshocks. These patterns suggest possible temporal associations between seismic and solar-geomagnetic variability at monthly timescales, although no formal statistical tests were applied. However, the small number of events, uncertainties in the seismic and magnetic datasets and the absence of formal statistical testing limit the strength of any conclusions and preclude causal inference. The correlations identified here should therefore be regarded as preliminary and do not imply that solar or geomagnetic activity directly triggers earthquakes; rather, they suggest that solar-magnetic parameters may offer complementary contextual information on the evolving state of the crust when used alongside conventional seismotectonic indicators, motivating further studies with larger datasets and more rigorous statistical and physical modeling frameworks.

کلیدواژه‌ها English

Earthquake precursor
seismic b-value
magnetic storms
solar proton
solar activity
Allan, R. S., & Mason, S. G. (1962). Particle behaviour in shear and electric fields I. Deformation and burst of fluid drops. Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences, 267(1328), 45-61.
Amitrano, D. (2003). Brittle‐ductile transition and associated seismicity: Experimental and numerical studies and relationship with the b value. Journal of Geophysical Research: Solid Earth, 108(B1).
Calandra, S., & Teti, D. (2024). Correlation Study: Triggering and Magnitude of Earthquakes in Italy (≥ M4. 3) in Relation to the Positions and Gravitational Forces of the Sun, Moon, and Planets Relative to Earth. New Concepts in Global Tectonics Journal, 12(1).
Cataldi, G., Cataldi, D., & Straser, V. (2016). Solar activity correlated to the M7. 0 Japan earthquake occurred on April 15, 2016. New Concepts in Global Tectonics Journal, 4(2), 202-208.
Cauzzi, C., Behr, Y., Le Guenan, T., Douglas, J., Auclair, S., Woessner, J., ... & Wiemer, S. (2016). Earthquake early warning and operational earthquake forecasting as real-time hazard information to mitigate seismic risk at nuclear facilities. Bulletin of Earthquake Engineering, 14, 2495-2512.
Chung, D. H., & Bernreuter, D. L. (1980). Seismic Safety Margins Research Program. Regional relationships among earthquake magnitude scales (No. NUREG/CR-1457; UCRL-52745). Lawrence Livermore National Lab., CA (USA).
Dascher-Cousineau, K.; Lay, T.; Brodsky, E.E. Two foreshock sequences post gulia and wiemer (2019). Seismol. Res. Lett. 2020, 91, 2843-2850.
de Arcangelis, L., Lippiello, E., Godano, C., & Nicodemi, M. (2008). Statistical properties and universality in earthquake and solar flare occurrence. The European Physical Journal B, 64, 551-555.
Galper, A. M., S. V. Koldashov, and S. A. Voronov. "High energy particle flux variations as earthquake predictors." Advances in Space Research 15.11 (1995): 131-134.
Gardner, J. K., & Knopoff, L. (1974). Is the sequence of earthquakes in Southern California, with aftershocks removed, Poissonian?. Bulletin of the seismological society of America, 64(5), 1363-1367.
Gibowicz, S.J. Variation of the frequency-magnitude relation during earthquake sequences in new zealand. Bull. Seismol. Soc. Am. 1973, 63, 517-528.
Godano, C., Lippiello, E., & de Arcangelis, L. (2014). Variability of the b value in the Gutenberg-Richter distribution. Geophysical Journal International, 199(3), 1765-1771.
Gulia, L.; Wiemer, S.; Vannucci, G. Pseudoprospective evaluation of the foreshock traffic-light system in Ridgecrest and implications for aftershock hazard assessment. Seismol. Res. Lett. 2020, 91, 2828-2842.
Gutenberg, B., & Richter, C. F. (1944). Frequency of earthquakes in California. Bulletin of the Seismological Society of America, 34(4), 185-188.
Han, Y., Guo, Z., Wu, J., & Ma, L. (2004). Possible triggering of solar activity to big earthquakes (Ms≥ 8) in faults with near west-east strike in China. Science in China Series G: Physics and Astronomy, 47, 173-181.
Jackson, D. D., & Kagan, Y. Y. (1999). Testable earthquake forecasts for 1999. Seismological Research Letters, 70(4), 393-403.
Keilis-Borok, V., & Soloviev, A. A. (Eds.). (2002). Nonlinear dynamics of the lithosphere and earthquake prediction. Springer Science & Business Media.
Loewe, C. A., & Prölss, G. W. (1997). Classification and mean behavior of magnetic storms. Journal of Geophysical Research: Space Physics, 102(A7), 14209-14213.
Marchitelli, V., Harabaglia, P., Troise, C., & De Natale, G. (2020). On the correlation between solar activity and large earthquakes worldwide. Scientific reports, 10(1), 11495.
Márquez-Ramírez, V. H., Nava, F. A., & Zúñiga, F. R. (2015). Correcting the Gutenberg-Richter b-value for effects of rounding and noise. Earthquake Science, 28, 129-134.
Marzocchi, W., Lombardi, A. M., & Casarotti, E. (2014). The establishment of an operational earthquake forecasting system in Italy. Seismological Research Letters, 85(5), 961-969.
Menvielle, M., & Berthelier, A. (1991). The K-derived planetary indices: description and availability. Reviews of Geophysics, 29(3), 415-432.
Moradi, A., Dezvareh, M., & Rahmati, M. (2016). Review of the statistics of earthquakes in Iran in 2016. In M. Naqvi, H. Rahimi, & A. Moradi (Chairs), 18th Iran Geophysics Conference, Tehran.
Naserieh, S., Karkooti, E., Dezvareh, M., et al. (2019). Analysis of artifacts and systematic errors of the Iranian Seismological Center’s earthquake catalog. Journal of Seismology, 23, 665-682. https://doi.org/10.1007/s10950-019-09828-z
Nikouravan, B. (2012). Do Solar Activities Cause Local Earthquakes?(New Zealand): Earthquake. International Journal of Fundamental Physical Sciences, 2(2), 17-20.
Novikov, V., Ruzhin, Y., Sorokin, V., & Yaschenko, A. (2020). Space weather and earthquakes: possible triggering of seismic activity by strong solar flares. Annals of Geophysics, 63(5), PA554-PA554.
Omori, F. (1894). On the aftershocks of earthquakes. Journal of the College of Science, Imperial University of Tokyo, 7, 111-200.
Papadopoulos, G.A.; Minadakis, G. Foreshock patterns preceding great earthquakes in the subduction zone of chile. Pure Appl. Geophys. 2016, 173, 3247-3271.
Papazachos, B.C. Foreshocks and earthquake prediction. Tectonophysics 1975, 28, 213-226.
Poudyal Lohani, Dibyashree & Nordin, Norhaiza & Roslan, Siti Nur Aliaa. (2025). Comparative Declustering Approaches for Seismic Data: Insights from Gardner‑Knopoff, Gruenthal, Reasenberg, and Uhrhammer in the Kathmandu Valley. Annals of Geophysics. 68. NH215. 10.4401/ag-9178.
Reasenberg, P. (1985). Second‐order moment of central California seismicity, 1969-1982. Journal of Geophysical Research: Solid Earth, 90(B7), 5479-5495.
Saltiel, S., Boyle, K., & Majer, E. (2011). Challenges in determining b value in the Northwest Geysers (No. LBNL-4594E). Lawrence Berkeley National Lab.(LBNL), Berkeley, CA (United States).
Senatorski, P. (2020). Gutenberg-Richter’sb value and earthquake asperity models. Pure and applied Geophysics, 177(5), 1891-1905.
Shi, Y., & Bolt, B. A. (1982). The standard error of the magnitude-frequency b value. Bulletin of the Seismological Society of America, 72(5), 1677-1687.
Simpson, J. F. (1967). Solar activity as a triggering mechanism for earthquakes. Earth and Planetary Science Letters, 3, 417-425.
Stein, S., & Wysession, M. (2009). An introduction to seismology, earthquakes, and earth structure. John Wiley & Sons.
Suyehiro, S. Difference between aftershocks and foreshocks in the relationship of magnitude to frequency of occurrence for the great chilean earthquake of 1960. Bull. Seismol. Soc. Am. 1966, 56, 185-200.
Suyehiro, S.; Asada, T.; Ohtake, M. Foreshocks and aftershocks accompanying a perceptible earthquake in central japan: On the peculiar nature of foreshocks. Pap. Meteorol. Geophys. 1964, 15, 71-88.
Tavares, M., & Azevedo, A. (2011). Influences of solar cycles on earthquakes. Natural Science, 3(06), 436.
Teng, G., & Baker, J. W. (2019). Seismicity declustering and hazard analysis of the Oklahoma-Kansas region. Bulletin of the Seismological Society of America, 109(6), 2356-2366.
Urata, N., Duma, G., & Freund, F. (2018). Geomagnetic Kp index and earthquakes. Open Journal of Earthquake Research, 7(1), 39-52.
Venegas-Aravena, P., & Cordaro, E. G. (2023). Analytical relation between b-value and electromagnetic signals in pre-macroscopic failure of rocks: insights into the microdynamics’ physics prior to earthquakes. Geosciences, 13(6), 169.
Wesseloo, J. (2014). Evaluation of the spatial variation of b-value. Journal of the Southern African Institute of Mining and Metallurgy, 114(10), 823-828.
Wu, K.T.; Yue, M.S.; Wu, H.Y.; Cao, X.L.; Chen, H.; Huang, W.Q.; Tian, K.Y.; Lu, S.D. Certain characteristics of Haicheng earthquake sequence. Acta Geophys. Sin. 1976, 19, 95-109, (In Chinese with English Abstract).
Wu, Y. M., Chen, S. K., Huang, T. C., Huang, H. H., Chao, W. A., & Koulakov, I. (2018). Relationship between earthquake b‐values and crustal stresses in a young orogenic belt. Geophysical Research Letters, 45(4), 1832-1837.
مجله ژئوفیزیک ایران

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