Ionosphere sounding for pre-seismic anomalies identification (INSPIRE): results of the project and perspectives for the short-term earthquake forecast

The INSPIRE project was dedicated to the study of physical processes and their effects in ionosphere which could be determined as earthquake precursors together with detailed description of the methodology of ionospheric pre-seismic anomalies definition. It was initiated by ESA and carried out by an international consortium. The full set of key parameters of the ionospheric plasma was selected based on the retrospective analysis of the ground-based and satellite measurements of pre-seismic anomalies. Using this classification the multi-instrumental database of worldwide relevant ionospheric measurements (ionosonde and GNSS networks, LEO-satellites with in situ probes including DEMETER and FORMOSAT/COSMIC ROC missions) was developed for the time intervals related to selected test cases. As statistical processing shows, the main ionospheric precursors appear approximately 5 days before the earthquake within the time interval of 30 days before and 15 days after an earthquake event. The physical mechanisms of the ionospheric pre-seismic anomalies generation from ground to the ionosphere altitudes were formulated within framework of the Lithosphere-Atmosphere- Ionosphere Coupling (LAIC) model. The processes of precursor’s development were analyzed starting from the crustal movements, radon emission and air ionization, thermal and atmospheric anomalies, electric field and electromagnetic emissions generation, variations of the ionospheric plasma parameters, in particular vertical TEC and vertical profiles of the electron concentration. The assessment of the LAIC model performance with definition of performance criteria for earthquake forecasting probability has been done in statistical and numerical simulation domains of the Global Electric Circuit. The numerical simulations of the earthquake preparation process as an open complex system from start of the final stage of earthquake preparation up to the final point–main shock confirms that in the temporal domain the ionospheric precursors are one of the most late in the sequence of precursors. The general algorithm for the identification of the ionospheric precursors was formalized which also takes into account the external Space Weather factors able to generate the false alarms. The importance of the special stable pattern called the “precursor mask” was highlighted which is based on self-similarity of pre-seismic ionospheric variations. The role of expert decision in pre-seismic anomalies interpretation for generation of seismic warning is important as well. The algorithm performance of the LAIC seismo-ionospheric effect detection module has been demonstrated using the L’Aquila 2009 earthquake as a case study. The results of INSPIRE project have demonstrated that the ionospheric anomalies registered before the strong earthquakes could be used as reliable precursors. The detailed classification of the pre-seismic anomalies was presented in different regions of the ionosphere and signatures of the pre-seismic anomalies as detected by ground and satellite based instruments were described what clarified methodology of the precursor’s identification from ionospheric multi-instrumental measurements. Configuration for the dedicated multiobservation experiment and satellite payload was proposed for the future implementation of the INSPIRE project results. In this regard the multi-instrument set can be divided into two groups: space equipment and ground-based support, which could be used for realtime monitoring. Together with scientific and technical tasks the set of political, logistic and administrative problems (including certification of approaches by seismological community, juridical procedures by the governmental authorities) should be resolved for the real earthquake forecast effectuation.In years 2014–2016 works were supported by the ESA Project “INSPIRE, ionosphere Sounding for Pre-seismic anomalies Identification Research (INSPIRE)” nr 4000,111,456/14/NL/ MV. The work is supported by the National Center for Research and Development, Poland, through Grant ARTEMIS (decision no. DWM/PL-CHN/97/2019, WPC1/ ARTEMIS/2019); The authors thank also the Ministry of Science and Higher Education (MSHE), Poland for granting funds for the Polish contribution to the International LOFAR Telescope “(MSHE decision no. DIR/ WK/2016/2017/05–1)” and for maintenance of the LOFAR PL-612 Baldy (MSHE decisions: no. 59/E-383/SPUB/SP/ 2019.1). This work is supported by the National Science Centre, Poland, through Grants 2017/25/B/ST10/00479 and 2017/27/B/ST10/02190.Peer ReviewedPostprint (published version

Longitudinal variation in the ionosphere-plasmasphere system at the minimum of solar and geomagnetic activity: Investigation of temporal and latitudinal dependences

International audienceWe use the Global Self-consistent Model of the Thermosphere, Ionosphere and Protonosphere (GSM TIP) as the first-principle calculation of the physical system state, the quick-run ionospheric electron density model (NeQuick) as the climatology background, and the International Reference Ionosphere-based Real-Time Assimilative Model for a global view of the ionospheric weather during a quiet period of the December 2009 solstice. The model computations are compared to the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) radio occultation profiles, CHAMP and Gravity Recovery and Climate Experiment in situ densities, and GPS total electron content (TEC). It is shown that the plasma density in the ionosphere is generally larger in the American/Atlantic longitudinal sector at any local time. The high-latitude density enhancements are visible in the GSM TIP output at different altitudes but are not reproduced by the NeQuick empirical model. Given that observational data confirm an existence of the high-latitude areas where ionospheric densities are elevated in the altitude range between 300 and 480 km, we conclude that the NmF2 maximum in the GSM TIP output can be trusted. Indeed, such high-latitude NmF2, ionospheric electron content, and TEC maxima in the American longitude sector form on the proper places as shown by the GSM TIP data, COSMIC and GPS observations. According to our results, the high-latitude maximum of NmF2 (1) manifests itself only when the integration over LT or UT of the global maps for 22 December 2009 includes nighttime, i.e., supporting an argument of its close association with the Weddell Sea Anomaly, and (2) also appears in the Ne distribution at altitudes above the F2 peak