Geospace perturbations induced by the Earth: The state of the art and future trends

Abstract

International audienceA systematic multi-parameter and multi-platform approach to study the slow process of earthquake preparation is fundamental to gain some insights on this complex phenomenon. In particular, an important contribution is the integrated analysis between ground geophysical data and satellite data. In this paper we review some of the more recent results and suggest the next directions of this kind of research. Our intention is not to detect a particular precursor but to understand the physics underlying the various observations and to establish a reliable physical model of the preparation phase before an impending earthquake. In this way, future investigation will search for suitable fore-patterns, which the physical model of multi-layers coupling predicts and characterizes by quasi-synchronism in time and geo-consistency in space. We also present alternative explanations for some anomalies which are not actually related to earthquakes, rather to other natural or anthropic processes

Latitudinal variation rate of geomagnetic cutoff rigidity in the active Chilean convergent margin

“…Another possible explanation of this apparent link between magnetic field, cutoff rigidity and geological systems arises from the instabilities in the CMB that are able to produce secular variations in the magnetic field on the Earth surface, and that corresponds to non-dipolar evolution of the geodynamo (Constable, 2007), since the topography of the CMB is significant in subduction zones, where the subducted slabs can generate downwelling or sinkholes in the deeper areas of the mantle and upwelling or outcrops in areas of divergence (Heirtzler, 2002;Koper, 2003;Hartmann and Pacca, 2009;Lassak et al, 2010;Calkins et al, 2012;Koelemeijer et al, 2012;Bayanjargal, 2013;Tarduno et al, 2015;Pavón-Carrasco and De Santis, 2016;Terra-Nova et al, 2016). However, the latest research on magnetic field and seismicity seems to come from the socalled lithosphere-atmosphere-ionosphere coupling (LAIC) (Hayakawa et al, 2015;De Santis et al, 2015Contoyiannis et al, 2016;Potirakis et al, 2016a, b;Oikonomou et al, 2017).…”

“…In addition, as the radial component of the Earth's magnetic field can be used as a measure of the variations in the CMB in periods of time of several months or years, we looked for significant variations in the geomagnetic spectra associated with other major geological events in the Chilean margin, as the latest research shows a statistically significant relation between geomagnetism and earthquakes (Hayakawa and Molchanov, 2002;Pulinets and Boyarchuk, 2004;Varotsos, 2005;Hayakawa et al, 2007Hayakawa et al, , 2015; Molchanov and Hayakawa, 2008;Liu, 2009;De Santis et al, 2015Contoyiannis et al, 2016;Potirakis et al, 2016a, b).…”

Ionospheric anomalies detected by ionosonde and possibly related to crustal earthquakes in Greece

“…A systematic statistical analysis of 13 years of ionosonde data from the Athens station has been undertaken, and the final result is that the method has great potential for use in EQ prediction, especially when it is integrated with other appropriate independent data (De Santis et al, 2015).…”

“…It is possible to reduce the number of false alarms using other observables in a multi-parametric integrated approach (e.g. De Santis et al, 2015).…”

“…Bolt, 1999), with potential coupling with atmosphere and ionosphere not only at the moment of the largest energy release due to the main fault rupture, but even during the long-term process of its preparation (e.g. Freund, 2000;Hayakawa and Molchanov, 2002;Pulinets and Boyarchuk, 2004;De Santis et al, 2015).…”