[M-IS10] Interdisciplinary studies on pre-earthquake processes

[MIS10-12] Geophysical multilayer and multi-parametric approach applied to study the earthquake preparatory phase: three case studies

*Dedalo Marchetti¹、Kaiguang Zhu¹、Alessandro Piscini²、Saioa A. Campuzano³、Dario Sabbagh²、Wenqi Chen¹、Serena D’Arcangelo^2,4、Domenico Di Mauro²、Xiaodan He¹、Martina Orlando²、Federica Poggio⁵、Xuhui Shen⁶、Maurizio Soldani²、Ting Wang¹、Jiami Wen¹、Zhima Zeren⁶、Donghua Zhang¹、Hanshou Zhang¹、Yiqun Zhang¹ (1.College of Instrumentation and Electrical Engineering, Jilin University, Changchun, 130061, China、2.Istituto Nazionale di Geofisica e Vulcanologia, Rome, 00143, Italy、3.Instituto de Geociencias IGEO (CSIC-UCM), Ciudad Universitaria, Madrid, 28040, Spain、4.Faculty of Physics, Complutense University of Madrid, Madrid, 28040, Spain、5.Università Degli Studi G.D'annunzio, Chieti, Italy、6.Space Observation Research Center, National Institute of Natural Hazards, MEMC, 100085, Beijing, China)

キーワード：earthquake, seismic acceleration, atmosphere, ionosphere

The understanding of the preparatory phase of an earthquake has been a challenging goal for the last decades and the problem of earthquake prediction is still open. Many studies focused on the time evolution of just one single parameter: from seismic precursors (e.g. (revised) accelerated moment release – Cianchini et al., 2020) to ionospheric disturbances (e.g. electron density and magnetic field variations – De Santis et al., 2019a). In all of these studies, some statistical evidence of perturbations of the specific observable before the earthquake has been properly detected. On the other hand, no studies have found a “precursor” that works for all or “most of all” earthquakes. The reason could be due to the complexity of the earthquake phenomena, so a geophysical multilayer approach could hopefully address such a problem (as suggested by the concept of “Geosystemics”, De Santis et al., 2019b).
In this study, three earthquakes will be presented as successful examples of the application of the Lithosphere-Atmosphere-Ionosphere Coupling (LAIC) approach: Mw = 6.5 Italy 2016 (part of a long seismic sequence started with Mw=6.0, Piscini et al., 2017, Marchetti et al., 2019a,b), Mw = 7.5 Indonesia 2018 (Marchetti et al., 2019c) and Mw = 7.7 Jamaica 2020 earthquakes.
These works are today possible thanks to long time available datasets, such as earthquake catalogues, climatological archives for atmosphere investigations, and several satellites to monitor the ionosphere, among them three Swarm ESA satellites constellation and China Seismo Electromagnetic Satellite (CSES) developed by China National Space Administration (CNSA) in partnership with Italian Space Agency (ASI) fully dedicated to search for possible ionospheric pre-earthquakes disturbances.
In these studies, the multi-parametric and multi-layers approach permitted the identification of some possible chain of phenomena that preceded the seismic event. However, all of them have the limitation to consider the earthquake as a point source (i.e. the hypocenter), instead of the extended seismic source with geographical orientation, which has a direction of movement associated with a focal mechanism. We will show that taking into account such tectonic information allows us to better understand the preparation phase of the earthquakes and start to understand why there are some differences in the identified results, even if the path toward a full understanding of the preparatory phase of the earthquakes or even a prediction is still long.

References:
- Cianchini G., et al., (2020). Revised Accelerated Moment Release Under Test: Fourteen Worldwide Real Case Studies in 2014–2018 and Simulations. PAGeoph. https://doi.org/10.1007/s00024-020-02461-9.
- De Santis, A., et al. (2019a). Precursory worldwide signatures of earthquake occurrences on Swarm satellite data. Sci. Rep. https://doi.org/10.1038/s41598- 019-56599.
- De Santis, A.; et al., (2019b). Geosystemics View of Earthquakes. Entropy , 21, 412. https://doi.org/10.3390/e21040412.
- Marchetti, D., et al., (2019a). Magnetic field and electron density anomalies from Swarm satellites preceding the major earthquakes of the 2016-2017 Amatrice-Norcia (Central Italy) seismic sequence. PAGeoph. ., 177, 305-319. https://doi.org/10.1007/s00024-019-02138-y.
- Marchetti D., et al., (2019b). Pre-earthquake chain processes detected from ground to satellite altitude in preparation of the 2016–2017 seismic sequence in Central Italy. RSoE., 229, 93-99. https://doi.org/10.1016/j.rse.2019.04.033.
- Marchetti D., et al., (2019c). Possible Lithosphere-Atmosphere-Ionosphere Coupling effects prior to the 2018 Mw=7.5 Indonesia earthquake from seismic, atmospheric and ionospheric data. JAES. https://doi.org/10.1016/j.jseaes.2019.104097.
- Piscini A., et al., (2017). “A Multiparametric Climatological Approach to Study the 2016 Amatrice–Norcia (Central Italy) Earthquake Preparatory Phase” published on PAGeoph. https://doi.org/10.1007/s00024-017-1597-8.