The LAIC phenomenon consists of the coupling of three geo-levels of the Earth, the lithosphere, the atmosphere and the ionosphere, so that phenomena occurring in the lithosphere can propagate into the atmosphere and affect higher layers reaching the ionosphere. From a seismological point of view, understanding the underlying physical processes that take place during the seismic preparation phase of high-energy events can be challenging, especially at the fault level. An alternative approach is to study whether during this preparation phase the lithosphere interacts with the atmosphere and ionosphere assuming a LAIC-type coupling.

Three main coupling mechanisms have been proposed. The first is related to the presence of p-holes (positive vacancies) that are generated during the preparation phase of an earthquake by stresses along the fault. These charged particles could alter the electrical circuit in the atmosphere, ionising it and creating instabilities in the mesosphere, eventually reaching the ionosphere (Freund, 2011). Another hypothesis is related to the migration of fluids along the fault and the release of radon gas that seems to be detected during the preparation phase of the most energetic seismic events. This release would affect the atmosphere, which would eventually propagate and generate disturbances in the ionosphere (Pulinets & Ouzounov, 2011). Finally, the third mechanism is based on the generation of acoustic gravity waves that would be generated before or a few minutes after an earthquake and would propagate to higher levels, affecting the ionosphere (Yeh & Liu, 1974).

All these observed disturbances at the three geo-levels have normally been observed through the detection of anomalies measured by ground stations. However, in recent years, with the launch of satellite missions such as DEMETER, Swarm or CSES, electromagnetic anomalies associated with seismic activity have been detected from space. This is a major step forward in the understanding of the preparation phase of the most energetic seismic events and highlights the need to use multi-parametric analyses to study this type of complex phenomena by combining not only seismological but also atmospheric and ionospheric information.