Ionosonde Data Analysis in Relation to the 2016 Central Italian Earthquakes

Alessandro Ippolito,Dario Sabbagh,Loredana Perrone,Angelo De Santis

doi:10.3390/geosciences10090354

Alessandro Ippolito, Dario Sabbagh + Show 2 more

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https://doi.org/10.3390/geosciences10090354

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Abstract

Ionospheric characteristics and crustal earthquakes that occurred in 2016 next to the town of Amatrice, Italy are studied together with the previous events that took place from 1984 to 2009 in Central Italy. The earthquakes with M larger than 5.5 and epicentral distances from the ionosonde less than 150 km were selected for the analysis. A multiparametric approach was applied using variations of sporadic E-layer parameters (the height and the transparency frequency) together with variations of the F2 layer critical frequency foF2 at the Rome ionospheric observatory. Only ionospheric data under quiet geomagnetic conditions were considered. The inclusion of new 2016 events has allowed us to clarify the earlier-obtained seismo-ionospheric empirical relationships linking the distance in space (km) and time (days) between the ionospheric anomaly and the impending earthquake, with its magnitude. The improved dependencies were shown to be similar to those obtained in previous studies in different parts of the world. The possibility of using the obtained relationships for earthquake predictions is discussed.

Highlights

Earthquakes (EQs) constitute one of the most energetic phenomena occurring in the Earth’s crust (e.g., [1])
In this paper we analyze variations of ionospheric parameters observed with ground-based ionosondes, namely, frequency of the ionospheric F2-layer (foF2) and parameters directly related to the sporadic E-layer (Es)
Hobara and Parrot [20] found a decrease in foF2 recorded by ionosonde stations in the Asian longitudinal sector for the isolated and very

Summary

Introduction

Earthquakes (EQs) constitute one of the most energetic phenomena occurring in the Earth’s crust (e.g., [1]). A possible coupling of large EQs with the atmosphere and ionosphere has to be considered during the long-term process of their preparation (e.g., [2,3,4,5]) and at the moment when the largest part of energy is released due to the main fault rupture [6,7,8,9,10,11]. Pre-EQ ionospheric anomalies are defined as middle-term precursors when they occur up to. Ionospheric parameters like critical frequency of the ionospheric F2-layer (foF2), electron temperature (Te ) at F2-region heights, total electron content (TEC), electron density (Ne ). In this paper we analyze variations of ionospheric parameters observed with ground-based ionosondes, namely, foF2 and parameters directly related to the sporadic E-layer (Es). Hobara and Parrot [20] found a decrease in foF2 recorded by ionosonde stations in the Asian longitudinal sector for the isolated and very

Methods

Discussion

Conclusion