Earthquake Preparation Research Articles

DIFFERENT-SCALE HETEROGENEITIES IN SEGMENTS OF SEISMOGENIC FAULTS AND THEIR INFLUENCE ON SLIP MODES

The paper presents some multidisciplinary research results on the structure of slip surfaces in segmented sections of tectonic faults in the Baikal region and Mongolia. The properties of subsurface (modern) and deep slip planes that came to the earth’s surface as a result of many-kilometer denudation in the upper part of the earth’s crust are studied at different levels-from macroscale to nanocrystals. Other types of heterogeneities characterizing the structure of fault slip zones are also considered. The presented data indicate a heterogeneous structure of tectonic faults. Their slip zones show both low friction in sections where strong mineral phases are replaced by weak minerals, and potentially unstable patches with high frictional resistance. The results obtained in a comprehensive study of geological conditions, under which different-scale heterogeneities emerge in exhumed fault segments, should be taken into account when developing rock mass models suitable for numerical simulation of earthquake preparation processes at the micro-, mesoand macroscales.

FORMATION OF THE NEAR-FAULT DAMAGE ZONE DURING DYNAMIC RUPTURE IN A CRYSTALLINE ROCK MASS

Many models for analyzing the dynamic propagation of seismogenic ruptures are based on solving classical problems of fracture mechanics. It is assumed that the fault is a shear fracture mode with uniformly distributed friction and stresses at the crack tip. Known fracture mechanics theories do not describe the formation of laterally oriented damage zones, i.e., in the direction perpendicular to the crack plane. Observational data indicate the presence of a fairly extensive zone of damaged material in the vicinity of the fault. This is the zone of dynamic influence where the material has an increased number of fractures, higher permeability and lower elastic wave velocities. A correct assessment of the properties and sizes of zones of dynamic influence is crucial for constructing adequate earthquake preparation models. This paper analyzes the development patterns and quantitative characteristics of the damage zone during dynamic earthquake rupture and quasi-static evolution of the fault. To estimate the size and mechanical characteristics of the near-fault damage zone caused by movement along the slip surface, it is convenient to use the value of the second invariant of the deviatoric stress tensor (shear intensity). Matching of the calculated value with one or another degree of rock mass damage can be done using measurement data from large-scale explosions, by comparing them with the calculation results. It is shown that coseismic movement along the fault leads to insignificant changes in the properties of the host rock mass. Although the longitudinal wave velocity near the fault decreases markedly by 30-35%, the permeability increases only by approximately a factor of three, and the increase in the degree of fracturing is almost unnoticeable. This means that the properties of the rock mass change due to the opening of preexisting cracks. Repeated movements do not radically change the characteristic dimensions and properties of the damage zone. It is concluded that the fault-affected zone is formed mainly at the quasi-static stage of the formation of a single main fault zone through the coalescence of individual macrofractures, and future seismogenic movements add to the already existing amount of fractures.

Multi-parametric study of seismogenic anomalies during the 2021 Crete earthquake (M=6.0)

It is well established that pre- and co-seismic irregularities in the earth’s atmosphere highly depend on a set of parameters. According to the Lithosphere-Atmosphere-Ionosphere Coupling (LAIC) mechanism, these parameters are associated with various channels (thermal, chemical, acoustic, electromagnetic, etc.) through which an earthquake (EQ) preparation process can have its anomalous phenomena. In this research, we perform a multi-parametric observation using various channels during a strong EQ (M = 6.0) on September 27, 2021, on Crete Island in Greece. We investigate the acoustic and electromagnetic channel using ground and satellite-based observation. We present the Atmospheric Gravity Wave (AGW) in the acoustic channel using the temperature profile computed from the SABER/TIMED instrument. In the electromagnetic channel, ionospheric Total Electron Content (TEC) is recorded by the GNSS-IGS station DYNG in Greece. This TEC information is also used in the acoustic channel anomaly by computing the wave-like structures in the small-scale fluctuation of the TEC profile. We compute energetic (30 to 100 keV) electron precipitation in the inner radiation belt from the NOAA satellite. We also investigate the outcomes of the SWARM satellite to compute the magnetic field and electron density profile. All the parameters show significant seismogenic anomalies (mostly enhancement) before the EQ. To understand each parameter’s temporal and spatial sensitivity, we present a comparison using the anomalies in each parameter.

Sudden modulation in the UHF wireless signals probably caused by the activation of pre‑earthquake processes. Case studies for the Balkans (SE Europe)

We study the atmospheric variations of broadband wireless signal propagation intensity correlated with pre‑earthquake processes. We have maintained ground observations in the VHF range of 1.8 and 3.5 GHz in Bulgaria (Southeast Europe), close to the border with Greece and Northern Macedonia, since 2012. The signal source is 1.8 GHz –LTE broadcasting cellular communication signal and the receivers are digital HF to SHF antennae collecting the data via mobile internet. Our observations revealed phenomena associated with a natural enhancement of the intensity of the signals (no change in the transmitting level) days/hours before the seismic events, even far from the observation region. We are presenting the results for four significant earthquakes in the area: (1) M5.6 on May 22, 2012, in Bulgaria, (2) M6.9 on May 24, 2014, in the Aegean Sea, Greece, (3) M6.5 on Nov 17, 2015, Lefkada, Greece, and (4) M6.3 of May 12, 2017, in Western Türkiye. Some changes in the atmospheric boundary layer (ABL), triggered by an intensification of radon and other released gases, could lead to a change in lower atmospheric conductivity. Although the intensity modulation was observed far (> 200 km) from the epicenter areas, the anomalies were always inside the estimates of the Dobrovolsky‑Bowman area of preparation. We examined the possible correlation between magnitude and the spatial size of the earthquake preparation zone in the Lithosphere‑Atmosphere-Ionosphere coupling (LAIC) framework.

Earthquakes and related anomalous electromagnetic radiation

According to the presented work, VLF/LF electromagnetic emissions might be declared as the main precursor of earthquakes since based on these very emissions, it might predict (M ≥ 5) inland earthquakes. As for ULF radiations, it governs some processes going on in the lithosphere-atmosphere-ionosphere coupling (LAIC) system. By these points, VLF/LF/ULF electromagnetic emissions have to consider more universal fields than other geophysical field anomalies during the earthquake preparation period up to aftershocks extinction.

Space-based GNSS radio signals to investigate ionospheric plasma changes preceding the 2016 Al Hoceima-Morocco earthquake, Mw=6.4

This paper examines abrupt variations in ionospheric electron density preceding the Al Hoceima earthquake (January 25th, 2016, Mw = 6.4, Northern Morocco). The observed anomalous behavior in the F2-ionospheric region, at about 350 km altitude, raises the possibility of a connection with impending seismic activity of moderate-to-great magnitude, supporting the hypothesis that Total Electron Content (TEC) variations could serve as potential earthquake precursors. For this purpose, we have exploited one of the main ionospheric keys, TEC, through a network of over one hundred dual-frequency Global Positioning System/Global Navigation Satellite Systems (GPS/GNSS) receivers. Through calculation algorithms based on spherical harmonic analysis of GPS/GNSS Observation-Navigation data, we were able to produce local ionospheric maps to restore the GPS-TEC signal and investigate potential ionospheric disturbances associated with this shallow-focus and strong earthquake. Since the ionospheric TEC is a function of the variability and dynamics of the Earth’s ionosphere, mainly time-space and solar-geomagnetic activities, we had to consider each of these disturbing factors separately. In fact, the seismic zone of Al Hoceima (Morocco, North Africa), at about 35°N latitude, belongs to the region of low geographical latitudes. In such regions the variations of the ionospheric layer are slight. Moreover, during the earthquake preparation period, space weather conditions exhibited a calm state characterized by low solar activity and the absence of geomagnetic storms. The adequate effects of these physical conditions allow us, through wavelet transform, to emerge solely signatures of earthquake-related ionospheric disturbances. Based on the seismo-ionospheric combination model, we have highlighted some ionospheric electron density irregularities that decreased abnormally, near the epicenter several days prior to the 2016 Al Hoceima main event. From these findings, we can state that such research provides a promising approach for predicting earthquakes through large fluctuations in the ionized shell of the Earth’s atmosphere, thereby offering the prospect of a life-saving seismic alarm.

Preface Special Issue: Developments in Earthquake Precursors Studies

This Special Issue of Annals of Geophysics is dedicated to present recent developments in the field of earthquake (EQ) precursors. Due to their potentially catastrophic nature, EQs have early attracted the attention of humans. During the last decades, a considerable amount of scientific effort has been devoted to the study of EQ precursors, aiming at EQ forecast. Prediction of large EQs, especially in the short-term, is of outmost importance for our society, since it could prevent, or at least restrict, their disastrous consequences, both in terms of infrastructure / material damages and in terms of casualties. It is clear that EQ preparation processes are complex and multifaceted, which call for a multidisciplinary approach. Many possible precursors have been reported and studied during the last decades, which include (just to mention some): foreshock activity, pre-slip effect, surface deformation, seismic electric signals (SES), ultra-low frequency (ULF) magnetic field anomalies, fracture-induced electromagnetic emissions (FEME) (fracture-induced electromagnetic radiation, FEMR), ULF/ELF (extremely low frequency) atmospheric electromagnetic radiation, atmospheric anomalies (such as SLHF, OLR etc.) and ionospheric (lower and upper regions) anomalies, lithosphere-atmosphere-ionosphere (LAI) coupling, even abnormal animal behavior.

Earthquake prediction based on the analysis of water level fluctuations in the control well

This study examines the methodology and results of earthquake forecasting based on the assumption that the earthquake preparation process can be linked to the development of rupture mechanisms. The analysis focuses on water fluctuations in a control monitoring well, which provides valuable information about the earthquake’s preparation period well in advance. Studies on the territory of the Kryvyi Rih iron ore basin (Kryvbas) confirmed that the underground waters in a deep well (815 m deep) depend on the processes of the current lithosphere deformations evidenced by the changing elastic-deformation state of the crust in tectonic areas. The Kryvyi Rih-Kremenchuk crust-mantle fault produces a system of different-scale faults in the crystalline basement which determine the hydrodynamics of the Kryvbas underground filtration. The earthquake preparation process exhibits clear indicators of the rupture process, characterized by a periodic component of water fluctuations superimposed on the main level-changing process during the preparatory phase. The frequency of the periodic component increases as the date of the earthquake approaches. With this approach, an earthquake with a magnitude of 4.1 inKryvbas was successfully predicted one and a half year before the event, based on monitoring water level fluctuations for 120 days between February and June 2016. The efficacy of forecasting local earthquakes was evaluated using the retro-forecast of earthquakes in Kryvbas on July 29, 2017. The methodology was validated through testing, confirming the initial assumptions. This technique was tested to predict the exacerbation of the seismic situation in the iron ore mining area caused by powerful blasting activities.

MONITORING OF CHANGES IN THE STRESS-STRAIN STATE OF GEOENVIRONMENT AT THE PETROPAVLOVSK GEODYNAMIC TESTING SITE BASED ON THE MULTI-INSTRUMENTAL BOREHOLE AND GPS DATA DURING THE ACTIVE PHASE OF PREPARING THE ZHUPANOVSKY EARTHQUAKE (JANUARY 30, 2016, Mw 7.2)

The paper presents the results of comparative analysis of the data regarding the multi-instrumental borehole monitoring data of changes in the geoenvironment stress-strain state and GPS data obtained in the time vicinity of the close strong Zhupanovsky earthquake. The purpose this study was to assess the feasibility of using GPS measurements on routine basis for effective monitoring of strong Kamchatka earthquakes in the area of Petropavlovsk-Kamchatsky. The Zhupanovsky earthquake active phase was chosen as a "test" time interval for comparing GPS and borehole monitoring data. This earthquake has been the strongest seismic event since 2000 in terms of the ratio of the earthquake focus length to the hypocentral distance. The time series borehole electromagnetic and geoacoustic data were compared with the dilatation series reflecting the relative changes in the area of a triangle composed of Kamchatka GPS observation network located in the Petropavlovsk geodynamic testing site. The analysis indicates a high degree of consistency in these time series. GPS data obtained during the active phase of the earthquake preparation is agree with the results of mathematical modeling expected values of volumetric strain on the daylight surface on the eve of the earthquake. A joint analysis of borehole and GPS data made it possible to specify the time limits for the stages of change in the stress-strain state of geoenvironment and to resolve ambiguity of interpretation of the electromagnetic and geoacoustic borehole measurement results at the final stage of preparing the Zhupanovsky earthquake.

Urban Seismic Networks: A Worldwide Review

Seismic networks in urban areas today represent key infrastructure to better address the tasks of earthquake preparation and mitigation in the pre-event phase, and are an important knowledge tool supporting disaster risk management during seismic crises and post-disaster recovery. In the last fifteen years, a decrease in instrumentation costs and the development of new low-cost devices have enhanced the deployment of several monitoring and experimental networks worldwide. This paper conducts a review of scientific work that refer to the deployment of Urban Seismic Networks (USN) in order to define the current state of the art. We collected a list of more than one hundred USNs worldwide that were operative within the period from 1994–2023. For each USN, we report the locations and objectives along with information about the timing, coverage, geometry, and technical characteristics (sensors and transmission). By reviewing all these aspects, this paper offers important insights to provide guidelines for new implementations, bearing in mind that the interest in monitoring urban areas is expected to continue to increase in the near future driven by population growth in urbanized areas.

An Investigation of University Students' Sustainable Earthquake Awareness Levels in Terms of Different Variables

Earthquakes have a significant impact on social, economic, and educational aspects of life. The negative effects of earthquakes on education and training are well documented. It is crucial to be adequately prepared to minimize these effects. This study aims to investigate the earthquake awareness of university students from a sustainable perspective. The survey model, a quantitative research method, was employed in this study. The research study comprised of 200 male (36.10%) and 354 female (63.90%) students who voluntarily participated from a university in the Western Black Sea Region during the 2022-2023 academic year. The Sustainable Earthquake Awareness Scale results show an average of 3.23 (Undecided) for the first factor, Earthquake Structure Relationship, 2.32 (Disagree) for the second factor, Earthquake Preparation Application, and 2.27 (Disagree) for the third factor, Earthquake Preparedness. The overall mean of the scale was 2.61 (Undecided). The results indicate that university students are not adequately prepared for possible earthquakes. There is no significant difference in Sustainable Earthquake Awareness Levels between male and female university students in all sub-factors and the total scale. Furthermore, as the grade level of university students increases, their sustainable earthquake awareness also increases. Furthermore, there is a notable contrast in the earthquake awareness levels of students from the faculties of engineering, health, and theology, with engineering students exhibiting a higher level of awareness. The study found no statistically significant difference between the sustainable earthquake awareness levels of university students and the number of floors in the building where they reside, both in terms of sub-factors and the overall scale.

Spatial–temporal evolution of soil gas Rn before two Ms ≥ 5.0 earthquakes in the mid-eastern of the Qilian fault zone (QLF)

The mid-eastern segment of the Qilianshan fault zone (QLF) on the northeastern margin of the Qinghai–Tibet Plateau is considered one of the key seismic hazard areas. The Zhangye Ms5.0 earthquake and Menyuan Ms6.9 earthquake are the two Ms ≥ 5.0 earthquakes in recent years. The spatio-temporal evolution of Rn across the fault before the two Ms ≥ 5.0 earthquakes were explored by combining a solid seismogenic model and numerical simulation results in this study. The results demonstrates the spatial distribution of Rn concentration intensity varies over time, indicating the evolving characteristics of fracture zone activity. The time-series variation characteristics are closely related the Zhangye Ms5.0 earthquake and Menyuan Ms6.9 earthquake. Overall, in the seismic source area and surrounding medium area of Zhangye Ms5.0 earthquake, the soil gas Rn anomaly across faults characterized by a turning upward trend after continuous decline. The closer to the source area, the more obvious the upward trend. For Menyuan Ms6.9 earthquake, the survey line (HT1) located in the main fracture zone of the earthquake and the survey line (HT7,30km from the epicenter) closer to the epicenter also showed a similar trend, while the other measurement lines in far-field exhibit declining trend before the Menyuan Ms6.9 earthquake. Therefore, the continuous decline trend of soil gas may be crucial information for medium-term earthquake preparation in the seismogenic zone, and the trend of turning upward after continuous decline is a significant signal of short-term seismogenic event in far-field. This research could improve the understanding of the anomalous features of soil gas precursors and tracking the active sections of the fault. According to the model, the earthquake area canseismic source area, the surrounding medium area be divided into three sections: the seismic source area, the surrounding medium area, and the fracture fragmentation area.

Satellite Registration of Anomalies of Various Geophysical Fields during the Preparation of Destructive Earthquakes in Turkey in February 2023

Satellite Registration of Anomalies of Various Geophysical Fields during the Preparation of Destructive Earthquakes in Turkey in February 2023

Months-long seismicity transients preceding the 2023 MW 7.8 Kahramanmaraş earthquake, Türkiye

Short term prediction of earthquake magnitude, time, and location is currently not possible. In some cases, however, documented observations have been retrospectively considered as precursory. Here we present seismicity transients starting approx. 8 months before the 2023 MW 7.8 Kahramanmaraş earthquake on the East Anatolian Fault Zone. Seismicity is composed of isolated spatio-temporal clusters within 65 km of future epicentre, displaying non-Poissonian inter-event time statistics, magnitude correlations and low Gutenberg-Richter b-values. Local comparable seismic transients have not been observed, at least since 2014. Close to epicentre and during the weeks prior to its rupture, only scarce seismic activity was observed. The trends of seismic preparatory attributes for this earthquake follow those previously documented in both laboratory stick-slip tests and numerical models of heterogeneous earthquake rupture affecting multiple fault segments. More comprehensive earthquake monitoring together with long-term seismic records may facilitate recognizing earthquake preparation processes from other regional deformation transients.

Quasi-coseismic variations and geosphere coupling associated with the strong 2023 Turkey earthquakes

On 6 February 2023, two massive shallow earthquakes of Mw 7.8 and Mw 7.5 occurred successively in Turkey. Unlike earlier studies on pre-seismic anomalous signals, here we focus on the co-seismic changes in ocean, land, and atmospheric parameters associated with these two earthquakes. The quasi-coseismic variations have been clearly observed in ocean, atmosphere, and snow parameters from satellite and reanalysis datasets. Our results show a decline in the seawater temperature and salinity, and enhancement in the chlorophyll-a concentration in the eastern Mediterranean Sea associated with the earthquakes. Over the epicentral region, the total ozone column and snowfall have been observed to increase with the occurrence of earthquakes. After a detailed analysis of the hourly parameters (atmospheric pressure, air temperature, relative humidity, and wind speed), we found the atmospheric pressure variation caused by the ground motion of seismic waves is the possible reason for the co-seismic changes. Based on the results discussed in this paper, a model of multi-geosphere co-seismic response associated with the 2023 Turkey events is proposed. Additionally, our results show that the crustal motion in the high mountain region within the earthquake preparation zone could be more sensitive prior to the earthquake due to the enhancement of electric field as suggested by the theory of positive holes.

Investigation of the Pre- and Co-Seismic Ionospheric Effects from the 6 February 2023 M7.8 Turkey Earthquake by a Doppler Ionosonde

During the catastrophic M7.8 earthquake in Turkey on 6 February 2023, anomalous effects were revealed in the ionosphere associated with various propagation mechanisms of seismogenic disturbance from the lithosphere up to the height of the ionosphere. Seventeen minutes after the main shock, a co-seismic disturbance was detected by a Doppler ionosonde on an inclined, 3010 km long, two-hop radio path “Kuwait—Institute of Ionosphere (Almaty)”. An appearance of acoustic waves at the height of 232 km in the ionosphere was fixed 568 s after arrival of the surface Rayleigh wave to the sub-ionospheric point, and such a delay agrees with the calculated propagation time of a vertically moving acoustic wave. The disturbance lasted 160 s, and its double amplitude was above 2 Hz, which noticeably exceeds the background fluctuation of Doppler frequency. The best coincidence between the waveforms of the Doppler signal and of the surface seismic wave was observed over the duration of the two leading periods, with correlation coefficients of 0.86 and 0.79, correspondingly. Pre-seismic effects in the ionosphere were revealed 8 days before the main shock both in the variations of the Doppler frequency and of the critical frequency f0F2. The probable origination mechanism of the pre-seismic ionospheric disturbances above the region of the earthquake preparation determined by the Dobrovolsky radius may be considered in accordance with the concept of lithospheric–atmospheric–ionospheric coupling.

Responses to the Preparation of the 2021 M7.4 Madoi Earthquake in the Lithosphere–Atmosphere–Ionosphere System

The purpose of this work is to investigate the responses of multiple parameters to the Madoi earthquake preparation. A new method is employed to extract anomalies in a geomagnetic field. The results show that there were abnormal changes in the lithosphere, atmosphere, and ionosphere near the epicenter before the earthquake. Despite the differences in spatial and temporal resolutions, the increase in geomagnetic residuals in the lithosphere exhibits similar temporal characteristics to the enhancement of thermal infrared radiation in the atmosphere. Two high–value regions are present in the ground–based geomagnetic high residuals and the ionospheric disturbances. The northern one is around the epicenter of the Madoi earthquake. Near the southern one, an M6.4 Yangbi earthquake occurred four hours before the Madoi earthquake. In this study, we have observed almost all of the physical phenomena that can occur during the preparation of an earthquake, as predicted using the electrostatic channel model. It can be inferred that the electrostatic channel is a possible mechanism for coupling between the lithosphere, atmosphere, and ionosphere during the Madoi earthquake.

Subduction as a Smoothing Machine: How Multiscale Dissipation Relates Precursor Signals to Fault Geometry

Understanding the process of earthquake preparation is of utmost importance in mitigating the potential damage caused by seismic events. That is why the study of seismic precursors is fundamental. However, the community studying non-seismic precursors relies on measurements, methods, and theories that lack a causal relationship with the earthquakes they claim to predict, generating skepticism among classical seismologists. Nonetheless, in recent years, a group has emerged that seeks to bridge the gap between these communities by applying fundamental laws of physics, such as the application of the second law of thermodynamics in multiscale systems. These systems, characterized by describing irreversible processes, are described by a global parameter called thermodynamic fractal dimension, denoted as D. A decrease in D indicates that the system starts seeking to release excess energy on a macroscopic scale, increasing entropy. It has been found that the decrease in D prior to major earthquakes is related to the increase in the size of microcracks and the emission of electromagnetic signals in localized zones, as well as the decrease in the ratio of large to small earthquakes known as the b-value. However, it is still necessary to elucidate how D, which is also associated with the roughness of surfaces, relates to other rupture parameters such as residual energy, magnitude, or fracture energy. Hence, this work establishes analytical relationships among them. Particularly, it is found that larger magnitude earthquakes with higher residual energy are associated with smoother faults. This indicates that the pre-seismic processes, which give rise to both seismic and non-seismic precursor signals, must also be accompanied by changes in the geometric properties of faults. Therefore, it can be concluded that all types of precursors (seismic or non-seismic), changes in fault smoothness, and the occurrence of earthquakes are different manifestations of the same multiscale dissipative system.

Observation of Ultra-Low-Frequency Wave Effects in Possible Association with the Fukushima Earthquake on 21 November 2016, and Lithosphere–Atmosphere–Ionosphere Coupling

The study presents seismogenic ULF (ultra-low-frequency) wave effects, as observed at our own new magnetic observatory at Asahi (geographic coordinates: 35.770° N, 140.695° E) in Chiba Prefecture. Our target earthquake (EQ) is a huge one offshore of Fukushima prefecture (37.353° N, 141.603° E) with a magnitude (M) of 7.4, which occurred at 20.59 h on November 21 UT, 2016. As a sampling frequency of 1 Hz was chosen for our induction magnetometer, we could detect both ULF wave effects: ULF radiation from the lithosphere, and the ULF depression effect, indicative of lower ionospheric perturbations. Observing the results of polarization analyses, we detected clear enhancements in ULF (frequency = 0.01–0.03 Hz) lithospheric radiation 14 days, 5 days, and 1 day before the EQ, and also observed a very obvious phenomenon of ULF (0.01–0.03 Hz) depression just 1 day prior to the EQ, which is regarded as the signature of lower ionospheric perturbations. These findings suggest that pre-EQ seismic activity must be present in the lithosphere, and also that the lower ionosphere was very much perturbed by the precursory effects of the Fukushima EQ. These new observational effects from our station have been compared with our previous investigations on different seismogenic topics for the same EQ, including the ULF observations at another magnetic observatory at Kakioka, belonging to the Japan Meteorological Agency (JMA), about 50 km north of our Asahi station, subionospheric VLF/LF propagation data (Japanese and Russian data), AGW (Atmospheric gravity wave) activity in the stratosphere, and satellite observation of particle precipitations. We have found that seismogenic anomalies of different parameters tend to happen just around the EQ day, but mainly before the EQ, and have found the chain-like tendency of the effects of the lithosphere, which seem to propagate upwards the lower ionosphere. Finally, we will try to gain a better understanding of the physical phenomena or mechanisms of the lithosphere–atmosphere–ionosphere coupling (LAIC) process during the EQ preparation phase.

Effect of Earthquake Preparation on Changes in Meteorological Characteristics (Based on the Example of the 2003 Chuya Earthquake)

Effect of Earthquake Preparation on Changes in Meteorological Characteristics (Based on the Example of the 2003 Chuya Earthquake)