Pre-seismic Electromagnetic Perturbations in Two Earthquakes in Northern Greece
Two medium-magnitude earthquakes separated by a distance of 230 km occurred within 34 days from each other in Northern Greece. A few hours before the manifestation of seismic activity, significant extra-low-frequency (ELF) perturbations were detected in a nearby Schumann resonance observation site. The typical spectrum of ELF measurements was deformed with the appearance of an enhanced spectral feature in the frequency range 20–25 Hz. A logit regression model was applied to the data to examine whether ELF perturbations could be considered as precursors of seismic activity. In general, two earthquakes so close to each other (in space, time, and magnitude) form a unique opportunity for the study of characteristic features of pre-seismic ultra-low-frequency (ULF)/ELF perturbations. Quantitative results from a simple nonlinear statistical model support the idea that there is some kind of physical interaction between seismic and atmospheric ELF activities, and that ELF measurements could potentially be used as a useful tool in the forecasting of seismic activity.
KeywordsSchumann resonances earthquakes preseismic signals
The authors express their gratitude to the Mariolopoulos-Kanaginis Foundation for the Environmental Sciences (grants nos. 119/20.04.2012 and 121/20.04.2016), and to the Empirikion Foundation for their generous support offered for the realization of this project. Warm thanks are also due to Mr. G. Skordos, ex-director of the high school at Doliana town, and the ecclesiastical committee of the same town for providing accommodation for personnel and equipment.
- Breiman, L. (2001). Random forests. In R. Schaphire (Ed.), Machine learning (Vol. 45, pp. 5–32). Dordrecht: Kluwer Academic Publishers.Google Scholar
- Greene, W. H. (2003). Econometric analysis (5th ed.). New Jersey: Prentice Hall.Google Scholar
- Hayakawa, M., & Molchanov, O. A. (2007). Seismo-electromagnetics as a new field of radiophysics: Electromagnetic phenomena associated with earthquakes. U.R.S.I. Radio Science Bulletin, No. 320, pp. 8–17.Google Scholar
- Hayakawa, M., Nickolaenko, A. P., Sekiguchi, M., Yamashita, K., Ida, Y., & Yano, M. (2008). Anomalous ELF phenomena in the Schumann resonance band as observed at Moshiri (Japan) in possible association with an earthquake in Taiwan. Natural Hazards and Earth System Sciences,8, 1309–1316.CrossRefGoogle Scholar
- Hayakawa, M., Ohta, K., Sorokin, V. M., Yaschenko, A. K., Izutsu, J., Hobara, Y., et al. (2010). Interpretation in terms of gyrotropic waves of Schumann-resonance-like line emissions observed at Nakatsugawa in possible association with nearby Japanese earthquakes. Journal of Atmospheric and Solar-Terrestrial Physics,72, 1292–1298.CrossRefGoogle Scholar
- Nickolaenko, A., & Hayakawa, M. (2002). Resonance in the earth-ionosphere cavity. Dordrecht: Kluwer Academic Publishers.Google Scholar
- Vallianatos, F., & Tzanis, A. (1999a). A model for the generation of precursory electric and magnetic fields associated with the deformation rate of the earthquake focus. In M. Hayakawa (Ed.), Seismic atmospheric and ionospheric electromagnetic phenomena associated with earthquakes (pp. 287–305). Tokyo: Terra Publishing Company.Google Scholar
- Votis, C., Tatsis, G., Christofilakis, V., Chronopoulos, S., Kostarakis, P., Tritakis, V. C., et al. (2018). A new portable ELF Schumann resonance receiver: Design and detailed analysis of the antenna and the analog front-end. EURASIP Journal on Wireless Communications and Networking. https://doi.org/10.1186/s13638-018-1157-7.CrossRefGoogle Scholar
- Xinyang, O., Xuemin, Z., Nickolaenko, A. P., Hayakawa, M., Xuhui, S., & Yuanqin, M. (2013). Schumann resonance observation in China and anomalous disturbance possibly associated with Tohoku M9.0 earthquake. Earth Sciences,26(2), 137–145.Google Scholar