The whole Earth is the emerging complex system composed by its interacting parts, as the lithosphere, the atmosphere and the ionosphere are. The coupling among Lithosphere-Atmosphere-Ionosphere (LAIC in brief) involves different physical observables from both satellites and ground-based observations (geomagnetic field, composition and kinematics of ionospheric plasma): conjugated analyses of satellite and ground-based data are nowadays a necessary requirement in Earth System studies in general. This is particularly true for the ionosphere and geomagnetic field observations aimed at pre-earthquake anomalies detection and understanding.

In the study of large seismic events, SAFE project will integrate satellite and ground EM data analyses with a corresponding seismic catalogue data collected in the epicentral areas. In particular

Revised Accelerated Seismic Release (R-ASR, De Santis et al., 2015) and Entropy of earthquake swarms (De Santis et al., 2011) are the preferred methods whose aim is the search of some recognizable patterns and/or indications about the seismic state of the area under inspection;

Ionospheric parameters of both the F2-layer and the sporadic E layer (Es), obtained from ionosondes, are investigated: formation of long-living (Δt ≈ 2-3 h) sporadic Es layers accompanied by an increase in others two ionospheric parameters (blanketing frequency of Es layer, fbEs, critical frequency of F2 layer, foF2) are considered as anomalies linked to pre-earthquake activities;

Electron density data from Swarm Electric Field Instruments, TEC fluctuations and scintillation anomalies, which literature reports as detected some days before the EQs are of interest for SAFE. Moreover, studies of GNSS-based ionospheric TEC data are aimed to produce maps over an area surrounding the epicentres in search of proper anomalies due to lithospheric sources.

Geomagnetic ground-based data help to remove (or avoid) the external contribution affecting the satellite data in order to distinguish contributions from much below the orbit (i.e. from atmosphere or lithosphere). They can even provide fundamental information about the changes of the conductivity distribution of the lithospheric volume beneath the observatories, e.g. through the Polarization ratio Z/H between vertical and horizontal magnetic components and the Transfer Function Entropy, useful to find anomalous periods in the data.

Satellite magnetic data are analysed in order to evidence anomalies related to seismic activities. Several algorithms and methods (e.g. wavelet transform and entropy) are means to exploit data looking for anomalies related to seismic events.

 

Publications