The scientific debate on the existence of possible precursors before large earthquakes has been wide and brought to not univocal conclusions. One observable alone is clearly insufficient to provide indications on the criticality of the seismic fault status. In particular, it’s fundamental to investigate how critical is the accumulation of stress on a seismogenic fault and how we can predict an incoming earthquake. Considering that the Earth is a complex system in which the geo-layers (lithosphere, atmosphere and ionosphere) interact, it seems possible to understand better the Earth’s system if we study it as a whole. This requires an integration of observations and data from several sources and instruments, from ground data to remote sensing satellites. Despite the technical obstacles, several works have been done in this direction in the last years, and they seem to confirm firstly that the geo-layers show alterations (i.e., anomalies) before earthquake occurrence; secondly, it seems that several mechanisms of coupling are possible. This last point is the present research topic, as further clarifications are required.In the presentation, several examples of couplings before the earthquakes will be shown; for example, the recent investigation of the Lushan (China) 2013 earthquake, which shows three possible couplings by different geophysical mechanisms at very different times before the earthquake (130 days, 45 days, and 2 weeks).For the more recent seismic event, it is possible to investigate the ionosphere layer with the precious data from China Seismo Electromagnetic Satellite (CSES-01), by its instruments such as Langmuir probes and magnetometers. The integration of CSES and ESA Swarm data allows us to define better the ionospheric disturbances possibly related to earthquake occurrence. These cases include Mw = 7.5 Indonesia 2018, Mw = 7.6 Papua New Guinea 2019, Mw = 7.7 Jamaica 2020 or Mw = 7.8 Turkey 2023 earthquakes.Finally, we are still far from predicting earthquakes but several steps toward a better understanding of the phenomena eventually associated with seismic events seem to be not far.  

In recent years, a lot of papers have been made investigating single case studies of Lithosphere-Atmosphere-Ionosphere-Coupling before earthquake occurrence by multiparametric researchers. So, a question naturally arises: Do we need to investigate another large earthquake?The answer is not trivial. Statistical studies are necessary and fundamental to support this research, as the occurrence of anomalies before an earthquake doesn’t prove that the anomalies are induced by the preparation of the earthquake. Contrariwise, by investigating statistically the time before the earthquake, it’s possible to compare if the rate of occurrence of specific anomalies is larger than the same rate in a non-seismic period, assessing the statistical significance of the pre-earthquake phenomenon. Anyway, when a lot of earthquakes are investigated at the same time, the details of the patterns of anomalies in the geo-layers are lost. For such a reason, the investigation of single case studies is precious if conducted in parallel with statistical investigations.In this framework, here, the investigation of a new earthquake is proposed: Mw = 7.2 14 August 2021 Haiti earthquake. The six months that preceded the Haiti earthquake are explored using data from the lithosphere, atmosphere, and ionosphere (among them with China's seismo-electromagnetic satellite and swarm satellites). Several anomalies have been depicted by different techniques. In particular, it’s very interesting to underline that all the geo-layers showed anomalies about two months before the seismic event: seismic accumulation of stress increased its slope, several atmospheric quantities underlined abnormal atmospheric conditions, and CSES-01 Ne depicted two consecutive days of ionospheric electron density in the six months preceding the earthquake. A final comparison with previously investigated earthquakes is provided trying to discuss the analogies and differences in the various events. In particular, the comparison with Mw = 7.7 Jamaica earthquake is crucial for the same availability of dataset, close location, and similar tectonic settings. The comparison could start to depict some reasons for the different patterns as the land or sea location of the epicenter.