In this publication we demonstrate how interdependent are our geophysical shells. The large-scale air pollution provided by the intensive volcano eruptions and dust storms from desert areas modify the electric properties of the troposphere creating the low conducting layers and increasing the column resistance for the vertical current flowing between the ionosphere and ground within the Global Electric Circuit (GEC). This modification leads to the local modulation of the ionospheric potential (IP) magnitude and hence to formation of the large-scale irregularities of electron concentration in the ionosphere. To reveal these phenomena, we use the differential GIM TEC mapping procedure showing specific features of the ionosphere reaction. In low latitude and equatorial regions we observe the formation of positive TEC anomalies not only over the area of air pollution but in the magnetically conjugated area as well. We can conclude that these phenomena pose the double error for Precise Point Positioning (PPP). To the danger of aircraft engines destroying is added the increase of navigational PPP errors due to sharp TEC gradients on the borders of the formed large-scale positive irregularities of electron concentration.

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 within situprobes 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 multi-observation 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 real-time 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.

The paper provides a comparative analysis of precursory phenomena in the ionosphere and atmosphere for two strong earthquakes of the same magnitude M7.1 that happened in the same region (North-East from Los Angeles) within a time span of 20 years, the Hector Mine and Ridgecrest earthquakes. Regardless of the similarity of their location (South-Eastern California, near 160 km one from another), there was one essential difference: the Hector Mine earthquake happened during geomagnetically disturbed conditions (essential in the sense of ionospheric precursors identification). In contrast, the quiet geomagnetic conditions characterized the period around the time of the Ridgecrest earthquake. The Hector mine earthquake happened in the middle of the rising phase of the 23-rd solar cycle characterized by high solar activity, while the Ridgecrest earthquake happened by the very end of the 24th cycle under very low solar activity conditions. We provide a comprehensive multi-factor analysis, determine the precursory period for both earthquakes and demonstrate the close similarity of ionospheric precursors. Unlike the majority of papers dealing with earthquake precursor identification based on the “abnormality” of observed time-series mainly determined by amplitude difference between “normal” (usually climatic) behavior and “abnormal” behavior with amplitudes exceeding some pre-established threshold, we used the technique of cognitive recognition of the precursors based on the physical mechanisms of their generation and the morphology of their behavior during the precursory period. These permits to uniquely identify precursors even in conditions of disturbed environment as it was around the time of the Hector Mine earthquake. We demonstrate the close similarity of precursors’ development for both events. The leading time of precursor appearance for the same region and similar magnitude was identical. For the Hector Mine it was 11 October 1999—5 days in advance—and for 2019 Ridgecrest it was 28 June—7 days before the mainshock and five days before the strongest foreshock.

We analyze retrospectively/prospectively the transient variations of six different physical parameters in the atmosphere/ionosphere during the M7.8 and M7.3 earthquakes in Nepal, namely: 1) outgoing longwave radiation (OLR) at the top of the atmosphere (TOA); 2) GPS/TEC; 3) the very-low-frequency (VLF/LF) signals at the receiving stations in Bishkek (Kyrgyzstan) and Varanasi (India); 4) Radon observations; 5) Atmospheric chemical potential from assimilation models; and; 6) Air Temperature from NOAA ground stations. We found that in mid-March 2015, there was a rapid increase in the radiation from the atmosphere observed by satellites. This anomaly was located close to the future M7.8 epicenter and reached a maximum on April 21–22. The GPS/TEC data analysis indicated an increase and variation in electron density, reaching a maximum value during April 22–24. A strong negative TEC anomaly in the crest of EIA (Equatorial Ionospheric Anomaly) occurred on April 21, and a strong positive anomaly was recorded on April 24, 2015. The behavior of VLF-LF waves along NWC-Bishkek and JJY-Varanasi paths has shown abnormal behavior during April 21–23, several days before the first, stronger earthquake. Our continuous satellite OLR analysis revealed this new strong anomaly on May 3, which was why we anticipated another major event in the area. On May 12, 2015, an M7.3 earthquake occurred. Our results show coherence between the appearance of these pre-earthquake transient’s effects in the atmosphere and ionosphere (with a short time-lag, from hours up to a few days) and the occurrence of the 2015 M7.8 and M7.3 events. The spatial characteristics of the pre-earthquake anomalies were associated with a large area but inside the preparation region estimated by Dobrovolsky-Bowman. The pre-earthquake nature of the signals in the atmosphere and ionosphere was revealed by simultaneous analysis of satellite, GPS/TEC, and VLF/LF and suggest that they follow a general temporal-spatial evolution pattern that has been seen in other large earthquakes worldwide.

The paper describes an approach that allows, basing on the data of multiparameter monitoring of atmospheric and ionospheric parameters and using ground-based and satellite measurements, to select from the data stream a time interval indicating the beginning of the final stage of earthquake preparation, and finally using intelligent data processing to carry out a short-term forecast for a time interval of 2 weeks to 1 day before the main shock. Based on the physical model of the lithosphere-atmospheric-ionospheric coupling, the precursors are selected, the ensemble of which is observed only during the precursory periods, and their identification is based on morphological features determined by the physical mechanism of their generation, and not on amplitude selection based on statistical data processing. Basing on the developed maquette of the automatic processing service, the possibility of real-time monitoring of the situation in a seismically active region will be demonstrated using the territory of the Kamchatka region and the Kuril Islands.

We analyze retrospectively the transient variations of four different physical parameters of atmosphere/ionosphere during the time of M7.5 od Sept 28, 2018 in Indonesia namely: (i) thermodynamic proprieties in the lower atmosphere, (ii) outgoing earth radiation (OLR) at the TOA, (ii) GPS/TEC and (iv) the very-low-frequency (VLF/LF) signals at the receiving station in Petropavlovsk-Kamchatski (RTK, Russia). We found that in the second part of September 2018 a rapid augment of satellite observed earth radiation in the atmosphere and the anomaly located in close vicinity to the future M7.5 epicenter reached the maximum on Sept 21-22. The GPS/TEC data analysis indicates an augment and variation in electron density reaching a maximum value during the Sept 26-27 periods. Two VLF/LF crossing wave paths NWC-RTK and JJY-RTK, have shown abnormal behavior of signals during on days Sept 26-28 two days before the earthquake. Our results show coherence between the appearance of pre-earthquake transient’s effects in atmosphere and ionosphere (with a short time-lag, from hours up to a few days) and the occurrence of 2018 M7.5 in Indonesia. Traveling ionospheric tsunami disturbances (TITDs) in the total electron content (TEC) induced by tsunami waves of the 28 September 2018 Mw 7.5 Sulawesi Indonesia earthquake are detected by of seven ground-based receivers of the global positioning system (GPS) in South Asia, Oceanic, Pacific areas. It is found that the origin is about 100 km North of the epicenter and the horizontal speed is of about 187 m/s.

Abstract—Specific features of the variation in the electron concentration in the ionosphere in front of strong (M ≥ 6) earthquakes in the most seismically active areas of Europe, Greece and Italy, are considered on the basis of long-term measurements. Vertical sounding data (variations of the critical frequency foF2) are analyzed to cover long periods of time before the GPS/GLONASS era, and variations of the vertical total electronic content are also analyzed with the advent of global navigation satellite systems receivers in the considered regions. This analysis is based on the results of previous publications that revealed features of ionospheric precursors such as self-similarity, which is expressed in the exceptional stability of electron concentration variation as dependence on the local time. Its graphic representation is called the ionospheric precursor mask. This stability, which is defined as deterministic variability, is confirmed by the multiyear measurement data presented in this work. One new result involves the regional features of the ionospheric precursor mask found for Italy, where the mask for earthquakes in central Italy (within a radius of 300 km north of Rome) and the mask for earthquakes in southern Italy (within a radius of 300 km south of Rome) differ in phase. A possible explanation of the observed regional features is proposed.

The physics of earthquake genesis at the latest stage of a seismic cycle has always been the subject of scientific interest and discussion. In such discussion and in model development, however, only solid Earth processes have been contemplated. Development of satellite technologies brought new insight to the problem: new types of anomalies in the atmosphere and ionosphere were discovered that appear a few days/weeks before the main shock within the zone of earthquake preparation. These anomalies were thoroughly investigated, and results of this research have demonstrated a high statistical confidence warrants their identification as short-term earthquake precursors. In this chapter we seek to clarify how information and energy are transported from underground to the upper and lower layers of the atmosphere, including near-Earth space. Owing to the interdisciplinary character of the model, it is very difficult to create a common code for all its physical and spatial domains. That is why the material presented here should be considered conceptual rather than modeling output. As an example, if in the boundary layer plasmachemistry instrumentation is applied, for ionospheric anomalies the electromagnetism approach is adopted. This conceptual approach, however, proved to be valid not only for earthquakes but also for other natural and technological disasters where air ionization occurs.

This paper summarizes the years of studies devoted to the self-similarity of anomalies originating in the ionosphere above the regions of the preparation of strong earthquakes. Using statistical processing of data on electron density variations obtained by methods of vertical sounding and measurements of the total electronic content, we have formed a pattern of similar variations observed at midlatitudes before strong earthquakes; we call it a precursor mask for earthquakes. It was found that the positive anomaly in the ionosphere formed at nighttime after sunset and ended at sunrise. In the case of strong earthquakes, the anomaly can last 12 h and emerge within a few days at the same local time. We propose a physical mechanism of anomaly formation in the ionosphere bound with the diurnal dynamics of the atmospheric boundary layer, which regulates the height distribution of cluster ions.

We apply experimental approach of the multiparameter monitoring of short-term earthquake precursors which reliability was confirmed by the Lithosphere-Atmosphere-Ionosphere Coupling (LAIC) model created recently [1]. A key element of the model is the process of Ion induced Nucleation (IIN) and formation of cluster ions occurring as a result of the ionization of near surface air layer by radon emanating from the Earth's crust within the earthquake preparation zone. This process is similar to the formation of droplet’s embryos for cloud formation under action of galactic cosmic rays. The consequence of this process is the generation of a number of precursors that can be divided into two groups: a) thermal and meteorological, and b) electromagnetic and ionospheric. We demonstrate elements of prospective monitoring of some strong earthquakes in Kamchatka region and statistical results for the Chemical potential correction parameter for more than 10 years of observations for earthquakes with M≥6. As some experimental attempt, the data of Kamchatka volcanoes monitoring will be demonstrated.

This paper describes the current understanding of the interaction between geospheres from a complex set of physical and chemical processes under the influence of ionization. The sources of ionization involve the Earth's natural radioactivity and its intensification before earthquakes in seismically active regions, anthropogenic radioactivity caused by nuclear weapon testing and accidents in nuclear power plants and radioactive waste storage, the impact of galactic and solar cosmic rays, and active geophysical experiments using artificial ionization equipment. This approach treats the environment as an open complex system with dissipation, where inherent processes can be considered in the framework of the synergistic approach. We demonstrate the synergy between the evolution of thermal and electromagnetic anomalies in the Earth's atmosphere, ionosphere, and magnetosphere. This makes it possible to determine the direction of the interaction process, which is especially important in applications related to short-term earthquake prediction. That is why the emphasis in this study is on the processes proceeding the final stage of earthquake preparation; the effects of other ionization sources are used to demonstrate that the model is versatile and broadly applicable in geophysics.

We analyze retrospectively/prospectively the transient variations of three different physical parameters of atmosphere during the time of M7.8 and M7.3 events in Nepal: outgoing earth radiation (OLR), GPS/TEC and the thermodynamic proprieties in the lower atmosphere. We found that in mid March 2015 a rapid augment of satellite observed earth radiation in atmosphere and the anomaly located in close vicinity to the future M7.8 epicenter reached the maximum on April 21-22. Our continuous satellite analysis revealed prospectively the new strong anomaly on May 3th, which was the reason to contemplate another large event in the area. On May 12, 2015 a large aftershock of M7.3 occurred. The analysis of air temperature from weather ground station near Katmandu shows analogous patterns with offset 1-2 days earlier to the satellite anomalies. The GPS/TEC data analysis indicates an augment and variation in electron density reaching a maximum value during April 22-24 period. A strong negative TEC anomaly in the crest of EIA (Equatorial Ionospheric Anomaly) has occurred on April 21st and strong positive on April 24th, 2015. Our preliminary results show correlation between the pre-earthquake atmospheric and ionospheric anomalies and the occurrence of 2015 M7.8 and M7.3 events in Nepal.