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Ionospheric total electron content (TEC) variations estimated from dual-frequency receivers of global positioning systems (GPS) can be used as a tool to detect possible seismo-ionospheric anomalies before strong earthquakes. In this study, possible seismo-ionospheric anomalies before the 2018 Papua New Guinea earthquake (6.0684°S, 142.7678°E, Febru...
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Dual frequency Global Positioning System (GPS) receiver in two nearby stations i.e. BESI (28.228 °N, 84.739 °E) and GHER (28.375 °N, 84.739 °E) located at almost same latitude and longitude are used to measure ionospheric total electron content (TEC) for the year 2015. Since Year of 2014- 2016 have been known as most active years in terms of geomag...
Ionospheric modelling is one of the most crucial approaches to study the activities of the ionosphere particularly in regions where experimental data are not readily available. This research aims to study the variations of Total Electron Content (TEC) in a low latitude east African station (Addis Ababa) by comparing experimental values of TEC from...
Global Positioning System (GPS) station displacements in this work are derived using the so-called precise point positioning (PPP) technique with low-cost singlefrequency (SF) receivers. In the SF PPP, the ionosphere delay is the largest error source if the satellite orbits and clocks are well modeled. We use two strategies to minimize the ionosphe...
Seismo-ionospheric abnormalities are typically detected using total electron content (TEC) measurements taken from satellites. In this study, global positioning system (GPS)-TEC data from 3 sites in the seismic zone of the magnitude 7.8 Turkey earthquake (EQ) of February 6, 2023, were examined with the ultimate aim of detecting their possible link...
The attention towards possible link of earthquakes (EQs) and ionosphere in the form of seismo ionosphere anomalies (SIAs) has increased exponentially by utilizing new data and more accurate observations. The integrated atmosphere and ionosphere monitoring satellites has played a decisive role in this development and provided detection and analysis...
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... In another analysis, large TEC enhancements were recorded before the M 7 Papua New Guinea EQ, where the authors claimed that the seismic TEC anomalies could also be observed during high geomagnetic activities (Ulukavak & Inyurt, 2020). As storm values are active before and after the main shocks. ...
The Global Positioning System (GPS) provides insights into the Earthquakes (EQs) ionospheric anomalies. Different space-and-ground parameters are used to observe EQ precursors. This paper uses the Total Electron Content (TEC) from nearby operating GPS stations to detect perturbation in the ionosphere before and after four EQs in Japan in 2011. In addition, the TEC variations in relation to the depth and magnitude of the EQs are noticed. The analysis shows significant variations in TEC to depth and magnitude in association with each main shock. TEC value abruption starts on 8 March and continues for 6 days in March. In April, TEC abnormalities start 5 days before and after the man shock. The geomagnetic Kp index is higher than four from March 10 to 12. The anomalies in this study are clearly associated with geomagnetic storms, as the Kp index is active. Moreover, the Dst index is below the negative 50 (nT) in the seismic period of March and April. The ionosphere parameters will define the severity of seismic activity in future.
... Different studies have set different criteria in order to filter out solar and geomagnetic influences on the ionosphere. Here in, the values of k_p≤3 and -30nT≤Dst≤30nT are adopted as quiet geomagnetic conditions [41][42][43][44][45][46]. The value is adopted as quiet solar conditions [20,47]. ...
... Different studies have set different criteria in order to filter out solar and geomagnetic influences on the ionosphere. Here in, the values of k_p≤3 and -30nT≤Dst≤30nT are adopted as quiet geomagnetic conditions [41][42][43][44][45][46]. The value is adopted as quiet solar conditions [20,47]. ...
... These parameters include electric and magnetic fields, gas emissions from the earth, as well as water levels and temperature, surface temperature, surface deformations, and seismicity [3,4]. In addition, changes in the ionosphere were investigated regarding their potential for earthquake predictions or early warnings [5][6][7][8]. Based on those observation, countries situated in seismically active zones regularly conduct monitoring and research in an attempt to reduce the impacts of earthquakes [4,[9][10][11][12]. ...
... During coring, a fault was identified between 93. 8 However, during the borehole drilling, the weathered wall was collapsed to the bottom, and subsequently, the screen was inserted between 63 and 68 m below the surface. Both the MW6 and MW7 are included in city land for recreational facilities. ...
Although there is skepticism about the likelihood of predictive success, research on the prediction of an earthquake through precursory changes in natural parameters, including groundwater, has continued for decades. One of the promising precursors is the changes in groundwater, i.e., the level and composition of groundwater, and the monitoring networks are currently operated to observe earthquake-related changes in several countries situated at the seismically active zone. In Korea, the seismic hazards had not been significantly considered for decades since the seismic activity was relatively low; however, the public demands on the management and prediction of earthquakes were raised by two moderate-size earthquakes which occurred in 2016 and 2017. Since then, a number of studies that were initiated in Korea, including this study to establish a pilot-scale groundwater-monitoring network, consisted of seven stations. The network is aimed at studying earthquake-related groundwater changes in the areas with relatively high potentials for earthquakes. Our study identified a potential precursory change in water levels at one particular station between 2018 and 2019. The observed data showed that most monitoring stations are sufficiently isolated from the diurnal natural/artificial activities and a potential precursory change of water level was observed at one station in 2018. However, to relate these abnormal changes to the earthquake, continuous monitoring and analysis are required as well as the aid of other precursors including seismicity and geodetic data.
Earthquakes are major natural disasters that cause loss of life and property. Predicting earthquakes in advance is highly important. In recent years, GNSS measurements have been used to predict earthquakes, particularly by analysing total electron content (TEC) values obtained from these measurements. However, it is crucial to accurately analyse the TEC changes influenced by space weather conditions and distinguish them from those caused by earthquakes. This study investigated the impact of the Pazarcık-Kahramanmaraş (Mw: 7.8) and Ekinözü-Kahramanmaraş (Mw: 7.5) earthquakes that occurred on February 6, 2023, on TEC changes. To achieve this goal, space weather conditions, such as the Kp, Dst (nT), F10.7 (sfu), P (\(N⁄c{m}^{3}\)), Bx (nT), By (nT), and Bz (nT) indices, were examined for one month before and after the earthquake occurred. Potentially active days were identified. After establishing space weather conditions, their impact on TEC changes was investigated. The results indicated that there was no significant influence of space weather conditions on TEC changes during the selected time frame, suggesting that these changes may be attributed to the earthquake. Additionally, CODE-TEC and ESA-TEC values for the selected time frame were obtained using the coordinates of 15 CORS-Tr stations in the earthquake region. The upper and lower boundary values of the TEC were determined, and days with anomalies were identified. As a result, it was found that there were days with a positive anomaly approximately 15–18 days before the occurrence of possible earthquakes, which could serve as a preparation period. Furthermore, postearthquake anomalies were suggested to potentially be caused by aftershocks.
Approximately 9 h after the first Kahramanmaras earthquake, which hit on the night connecting February 5–6, earthquake institutes report a second earthquake with almost the same destructiveness. The name of this devastating event that shocks the ground with the break in the Eastern Anatolian Fault Line is Turkey’s second Southeastern earthquake. Mw 7.5, Ekinözü, Kahramanmaras earthquake hits at 10:24 UT on February 6, 2023, from a depth of 7.4 km. The second southeastern earthquake centered in Ekinözü, which caused intense loss of life in 10 provinces in the southeast of the country, is also felt in Syria, Iraq, Egypt, Lebanon, and Cyprus bordering Turkey, just like the first one. This discussion is dedicated to the folks who have suffered unbearable trauma. The discussion tries to detect the precursors of the earthquake through ionospheric TEC anomaly. The bounds of the anomaly are specified using some statistical instruments. The Fourier transformation governs the spectral analysis of the time-domain TEC atlas. Anomaly reading with the aid of the TEC atlas is based on the earthquake, space weather conditions, solar activity, and geomagnetic storm (coincided with the same time period). As a result of the analysis, the TEC anomaly is detected in the ionosphere on February 2 and 3 before the earthquake and on February 11, 15, 16, and 21 after the earthquake. The study likely detects precursors three days before the Ekinözü earthquake.
Earthquakes in the world from past to present have caused many loss of life and property. Earthquake forecasting studies are very important in order to prevent destructive effects of these loss of life and property. Total electron content (TEC) is a component that can be easily used to predict natural disasters such as earthquakes. TEC values can be calculated according to the desired location with the help of dual-frequency GNSS receivers and GPS satellites surrounding the whole world. However, it is impossible to predict a possible earthquake with only TEC values. For this purpose, TEC values should be examined together with indices such as space weather conditions indices, and then a possible forecast scenario should be determined. In this study, GPS-TEC anomalies were investigated with possible causes of ionospheric anomalies based on space weather conditions (SWC) indices such as solar activity (EUV and F10.7), geomagnetic activity (Dst), geomagnetic storm (Kp), magnetic field changes (Bz), proton density (Np) changes in the Sivrice-Elazığ earthquake (Mw 6.8) that occurred on January 24, 2020, and the Seferihisar (Izmir) earthquakes (Mw 6.6) that occurred on October 30, 2020, in the Aegean Sea off the coast of Seferihisar-Izmir.
This study evaluated an intense geomagnetic storm two days before, on the day of the magnetic storm (26 August 2018), and two days after, for a total of 5-daily global navigation satellite system (GNSS) measurements. The assessments were carried out for eight continuously operation reference stations-Turkey (CORS-TR) stations located in the province of Konya, Turkey. The change in the ionosphere layer caused by the geomagnetic storm was analyzed in terms of the total electron content (TEC) values. The analysis revealed that positive and negative anomalies had occurred on the day of the magnetic storm, the day before, and the day after. The statistic tests and correlation coefficient were calculated between regional and global ionosphere models. The global model that best fit the regional model was determined by comparing the regional values obtained from the GNSS measurements with the CODE, IRI-2016, and IRI-Plas. Besides, the geomagnetic storm, solar wind parameters (Bz, E, P, N, v), and geomagnetic activity indices (Dst, ap, Kp) were examined. As a result of the study, the global model that best fit the ionosphere model found using the regional TEC values was obtained using CODE TEC values. Moreover, the study demonstrated that magnetic storm-induced changes in the ionosphere could be detected using GNSS stations located in Turkey. Besides, the possible effects of the intense geomagnetic storm were propounded by the TEC anomalies.
This study examines ionospheric total electron content (TEC) perturbations from six International Global Navigation Satellite System stations (GNSS) including GUAT-Guatemala, SSIA-El Salvador, INEG-Mexico, MANA-Nicaragua, MDO1-United States of America, and BOGT- Colombia for several days around the occurrence of a major earthquake (M 7.4 and depth 20.0 km) in Mexico, June 23, 2020 at 10:29 Local Time (LT). The INEG station in the North-Northwest of the epicenter at a distance of about 936 km indicated a positive TEC anomaly on June 18, 2020, which can be possibly viewed as an earthquake precursor due to its occurrence during a quiet geomagnetic storm and inactive solar activity. Study findings reveal that other TEC perturbations may not be related to the earthquake, because they appeared during geomagnetic activities. Moreover, the atmospheric parameters have significant and synchronous deviations from the earthquake epicenter on June 13, 2020. The highest atmospheric chemical potential (ACP) is about 0.010 eV, atmospheric air temperature has positive deviation of 3.937 °C at 15:00 LT, the lowest atmospheric relative humidity has negative deviation of 25.387% at 13:00 LT and outgoing longwave radiation (OLR) 27.58 W.m⁻². Observations validate that in the earthquake preparation zone, variations in atmospheric air temperature and relative humidity reach at peak value during 10 days prior to the impending earthquake event with the later perturbations in the ionosphere.
