Multiparametric and multilayer investigation of global earthquakes in the World by a statistical approach
Authors: Marchetti Dedalo , Zhu Kaiguang , De Santis Angelo , Campuzano Saioa A. , Zhang Donghua , Soldani Maurizio , Wang Ting , Cianchini Gianfranco , D’Arcangelo Serena , Di Mauro Domenico , Ippolito Alessandro , Nardi Adriano , Orlando Martina , Perrone Loredana , Piscini Alessandro , Sabbagh Dario , Shen Xuhui , Zhima Zeren , Zhang Yiqun ,   Zhu Kaiguang's earthquake research group in Jilin University
Published: March 2022

&lt;p&gt;Earthquake prediction has always been a challenging task, and some researchers have proposed that it is an even impossible goal, concluding earthquakes are unpredictable events. Such a conclusion seems too extreme and in contrast with several pieces of evidence of alterations recorded by several instrumentations from the ground, atmosphere, and more recently by Earth Observation satellite. On the other side, it is clear that searching the &amp;#8220;perfect precursor parameter&amp;#8221; doesn&amp;#8217;t seem to be a good way, since the earthquake process is a complex phenomenon. In fact, a precursor that works for one earthquake does not necessarily work for the next one, even on the same fault. In some cases, another problem for precursors identification is the recurrency time between the earthquakes, which could be very long and, in such cases, we don&amp;#8217;t have comparable observations of earthquakes generated by the same fault system.&lt;/p&gt;&lt;p&gt;In past years, we concentrated mainly on two aspects: statistical and single case study; the first one consists of some statistical evidence on ionospheric disturbances possibly related to M5.5+ earthquakes (e.g., presented at&amp;#160;EGU2018-9468, and published by De&amp;#160;Santis&amp;#160;et al., Scientific Report, 2019), furthermore, some clear signals in the atmosphere statistically preceded the occurrence of M8+ events (e.g., presented at&amp;#160;EGU2020-19809). On the other side, we also investigated about 20 earthquakes that occurred in the last ten years, some of them by a very detailed and multiparametric investigation, like the M7.5 Indonesia earthquake (presented at&amp;#160;EGU2019-8077&amp;#160;and published by Marchetti et al., JAES, 2020), or the Jamaica earthquake investigation presented at the last&amp;#160;EGU2021-15456. We found that both approaches are very important. Actually, the statistical studies can provide proofs that at least some of the detected anomalies seem to be related to the earthquakes, while the single case studies permit us to explore deeply the details and the possible connections between the&amp;#160;geolayers&amp;#160;(lithosphere, atmosphere and ionosphere).&lt;/p&gt;&lt;p&gt;In this presentation, we want to show an update of the statistical study of the atmosphere and ionosphere, together with a new statistical investigation of the seismic acceleration before M7.5+ global earthquakes.&lt;/p&gt;&lt;p&gt;Finally, we demonstrate that it is essential to consider the earthquake not as a point source (that is the basic approximation), but in all its complexity, including its focal mechanism, fault rupture length and even other seismological constraints, in order to try to better understand the preparation phase of the earthquakes, and the reasons for their different&amp;#160;behaviour. These studies give hope and fundamental (but not yet sufficient) tools for the possible achievement, one day, of earthquakes prediction capabilities.&lt;/p&gt;