Analysis of space- and ground-based parameters prior to an earthquake on 12 December 2009 (original) (raw)
Related papers
2010
Using IAP (plasma analyzer) and ISL (Langmuir probe) experiments onboard DEMETER (Detection of Electromagnetic Emissions Transmitted from Earthquake Regions) satellite and GPS (Global Positioning System) measurements, we have statistically analyzed the variations of the electron and ion densities to search for disturbances in the vicinity of four large earthquakes prior to events. The indicesDst andKp were used to distinguish pre-earthquake anomalies from the other anomalies related to the geomagnetic activities. For each studied case, a very good agreement was found between the different parameters estimated by DEMETER and GPS data in the detection of pre-seismic anomalies. Our statistics results show that the anomalous deviations prior to earthquakes have different sign from case to case, and that their amplitude depends on the magnitude of the earthquake. It has also been found that the electron density measured by the ISL experiment at night detects anomalous variations signific...
The present paper considers possible physical mechanisms of the geophysical phenomena which may accompany earthquake preparation process and are explained on the basis of the model of generation of electromagnetic emissions detected before earthquake, where a complex process of earthquake preparation and its realization are considered taking into account distributed and conservative systems properties. The present paper considers possible physical mechanisms of the geophysical phenomena which may accompany earthquake preparation process and expose themselves several months, weeks or days prior to earthquakes. Such as: Changing of intensity of electro-telluric current in focal area; Perturbations of geomagnetic field in forms of irregular pulsations or regular short-period pulsations; Perturbations of atmospheric electric field; Irregular changing of characteristic parameters of the lower ionosphere (plasma frequency, electron concentration , height of D layer, etc.);Irregular perturbations reaching the upper ionosphere, namely F2-layer, for 2-3 days before the earthquake; Increased intensity of electromagnetic emissions in upper ionosphere in several hours or tenths of minutes before earthquake; Lighting before earthquake; Infrared radiation; Total Electron Content (TEC) anomalies. It is obvious that all above mentioned phenomena are not observed before every earthquake and do not have a place with noted sequence. Physical mechanisms of mentioned phenomena are explained on the basis of the model of generation of electromagnetic emissions detected before earthquake, where a complex process of earthquake preparation and its realization are considered taking into account distributed and conservative systems properties. § 2. Changing of Intensity of Electro-Telluric Current in Focal Area and ULF Magnetic Pulsations It is proved, that dynamic processes in the earthquake preparation zones can produce current systems of different kinds which can be local sources for electromagnetic waves at different frequencies, including ULF. High frequency waves attenuate so rapidly that they cannot be observed on the earth's surface, whereas ULF waves can propagate through the crust and reach the earth's surface [11, 17, 36]. Thus, in ground-based observations, we could expect some ULF signals of seismic origin of the order (0.01 Hz), observed in both geoelectric and geomagnetic fields [6, 16, 33, 34]. Furthermore, it should be stated that with the view of reliability studies results of geomagnetic field perturbation it is necessary to exclude magnetosphere influence (21). According to computations made by Chapman and Witenhead, meridian telluric component variation is generated by induction as a result of latitudinal magnetic component variation, while meridian magnetic component variation is immediate result of latitudinal telluric component variation (2).
Anomalous Behavior of GPS Based Total Electron Content (TEC) Associated With Earthquakes
Anomolous behaviour of the ionosphere prior to the earthquake was reported as early as in 1982. Since then variation in ionospheric parameters like foF2, foEs, TEC and characteristics of turbulence have been examined extensively. While most of the ionospheric studies have been carried out using ground based ionosonde and satellite radio beacon, considerable emphasis has been given recently on GPS (Global Positioning System) based total electron content (TEC) measurements. It has been fairly well established that strong earthquakes (M>5) preparation can cause anomalous total electron content (TEC) variations. To detect seismo-ionospheric disturbances in the TEC we used the data obtained from GPS Ionospheric Scintillation and TEC monitoring (GISTM) system which is in operation at Agra, India (Geographic Lat. 27.2 0 N, Long. 78 0
A study of ionospheric precursors associated with the major earthquakes occurred in Pakistan region
The GPS-TEC measurements have been in progress at Agra station (27.2 o N, 78 o E), India since 01 April 2006. In the present paper, we analyze the GPS-TEC data for two months of April and September, 2013 in which two major earthquakes (M > 7) occurred in the adjoining region of Pakistan. We use the quartile based statistical technique for the analysis of data and identify the significant precursors associated with the earthquakes. These precursors occurred on different days in the interval of 2-10 days prior to the earthquakes. We also examine the effect of geomagnetic storms on the total electron content (TEC) data and find that the precursors are not influenced by the storms. The cause of the precursors is E × B drift with the electric field generated over seismic regions and penetrated the ionosphere.
The dual-frequency satellite-based measurements from Global Positioning System (GPS) may provide feasible ways of studying and potentially detecting of earthquake (EQ) related anomalies in the ionosphere. In this paper, GPS based Total Electron Content (TEC) data are studied for three major M > 7.0 EQs in Nepal and Iran-Iraq border during 2015-2017 by implementing statistical procedures on temporal and spatial scale. Previous studies presented different time interval of pre-seismic ionospheric anomalies, however, this study showed that EQs ionospheric precursors may occur within 10 days. Furthermore, the ionospheric anomalies on the suspected day occurred during UT = 08:00-12:00 h before the main shock. The Global Ionospheric Map TEC (GIM-TEC) data retrieved over the epicenter of M7.8 (Nepal EQ) showed a significant increase of 6 TECU on
Variations in the total electron content of the ionosphere during preparation of earthquakes
2011
The morphological features in the deviations of the total electron content (TEC) of the iono sphere from the background undisturbed state as possible precursors of the earthquake of January 12, 2010 (21:53 UT (16:53 LT), 18.46° N, 72.5° W, 7.0 M) in Haiti are analyzed. To identify these features, global and regional differential TEC maps based on global 2 h TEC maps provided by NASA in the IONEX format were plotted. For the considered earthquake, long lived disturbances, presumably of seismic origin, were localized in the near epicenter area and were accompanied by similar effects in the magnetoconjugate region. Both decreases and increases in the local TEC over the period from 22 UT of January 10 to 08 UT of January 12, 2010 were observed. The horizontal dimensions of the anomalies were ~40° in longitude and ~20° in latitude, with the magnitude of TEC disturbances reaching ~40% relative to the background near the epicenter and more than 50% in the magnetoconjugate area. No significant geomagnetic disturbances within January 1-12, 2010 were observed, i.e., the detected TEC anomalies were manifestations of interplay between processes in the lithosphere-atmosphere-ionosphere system.
Pre-earthquake ionospheric anomalies registered by continuous GPS TEC measurements
In this paper we examine pre-earthquake ionospheric anomalies by the total electron content (TEC) derived from a ground-based receiver of the Global Positioning System (GPS). A 15-day running median of the TEC and the associated inter-quartile range (IQR) are utilized as a reference for identifying abnormal signals during all of the 20 M > = 6.0 earthquakes in the Taiwan area from September 1999 to December 2002. Results show that the pre-earthquake ionospheric anomalies appear during 18:00-22:00 LT (LT=UT+8 h) within 5 days prior to 16 of the 20 M > = 6.0 earthquakes. This success rate of 80% (=16/20%) suggests that the GPS TEC is useful to register pre-earthquake ionospheric anomalies appearing before large earthquakes.
Earthquake prediction, ionospheric total electron content, and three earthquakes in California
Thermal Science, 2018
Because it is a newer and unproven technique, ionospheric seismology is still accepted as a phenomenon by a lot of scientists. However, research in this subject is rapidly increasing in the last decade. According to the ionospheric seismology, the mechanical energy accumulated by the compression of the rocks before the big earthquakes is released from the ground by creating a positive hall. These processes at the ground-to-air interface can lead to the injection of massive amounts of air ions into the lower atmosphere [1]. As a result of the injection, the earthquake lights, temperature rising, the pressure in the troposphere, radio frequencies distortions, and total electron content perturbation in ionosphere occur. Therefore, even if it does not enough alone, this parameter can be contributing to earthquake predict. It has been supported with several instances of manuscript. In this study, ionospheric total electron content was calculated for each station and satellite using GPS s...
The GPS total electron content (TEC) of the global ionospheric map (GIM) is employed to simultaneously observe seismo-ionospheric anomalies during an M8.0 earthquake near Wenchuan, China on 12 May 2008. It is found that TEC above the forthcoming epicenter anomalously decreases in the afternoon period of day 6 to 4 and in the late evening period of day 3 before the earthquake, but enhances in the afternoon of day 3 before the earthquake. The spatial distributions of the anomalous and extreme reductions and enhancements indicate that the earthquake preparation area is about 1650km and 2850km from the epicenter in the latitudinal and longitudinal directions, respectively. On the other hand, a network of 6 ground-based GPS receivers in China is employed to study traveling ionospheric disturbances triggered by the Wenchuan earthquake (TIDEs). The network detects 5 TIDEs in the Southside of the epicenter area. A study on the distances of the detected TIDEs to the epicenter vs. their associated traveling times shows that the horizontal speed is 600 m/s. Applying the circle method, we find that the 5 circles intercept a point right above the epicenter when the horizontal speed of 600 m/s is given. Global searches of the ray tracing and the beam forming techniques are employed to confirm the 5 TIDEs being induced by the Wenchuan Earthquake. Results show that TEC variations before the earthquake resulted from seismo-ionospheric signals (electromagnetic mechanisms) are much greater than those after caused by vertical motions of the Earth's surface (mechanical mechanisms).