Statistical characteristics of seismo-ionospheric GPS TEC disturbances prior to global Mw≥5.0 earthquakes (1998–2014)

Shah, Munawar; Jin, Shuanggen

doi:10.1016/j.jog.2015.10.002

Cited by 102 publications

(30 citation statements)

References 34 publications

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“…Pundhir et al [2015] studied the April 2013 M7.8 Pakistan earthquake to show GPS TEC data anomaly at Agra, 5-7 days prior to it. Shah and Jin [2015], by examining global M ≥ 5 earthquake events during 1998-2014 using TEC from GIMs, showed that ionospheric anomaly occurs for events having M ≥ 6 and focal depth less than 60 km. Detection of Electromagnetic Emissions Transmitted from Earthquake Regions data were analyzed by Liu et al [2015] to show nighttime electron and ion density depression and daytime ion temperature enhancement 1-6 days prior, over the epicenter of May 2008 M8 Wenchuan earthquake.…”

Section: Introductionmentioning

confidence: 99%

Preearthquake anomalous ionospheric signatures observed at low‐mid latitude Indian station, Delhi, during the year 2015 to early 2016: Preliminary results

Gupta

Upadhayaya

2017

JGR Space Physics

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We have analyzed five major earthquake events measuring greater than 6 on Richter scale (M > 6) that occurred during the year 2015 to early 2016, affecting Indian region ionosphere, using F2 layer critical parameters (foF2, hmF2) obtained using Digisonde from a low‐mid latitude Indian station, Delhi (28.6°N, 77.2°E, 19.2°N geomagnetic latitude, 42.4°N dip). Normal day‐to‐day variability occurring in ionosphere is segregated by calculating F2 layer critical frequency and peak height variations (ΔfoF2, ΔhmF2) from the normal quiet time behavior apart from computing interquartile range. We find that the ionospheric F2 region across Delhi by and large shows some significant perturbations 3–4 days prior to these earthquake events, resulting in a large peak electron density variation of ~200%. These observed perturbations indicate towards a possibility of seismo‐ionospheric coupling as the solar and geomagnetic indices were normally quiet and stable during the period of these events. It was also observed that the precursory effect of earthquake was predominantly seen even outside the earthquake preparation zone, as given by Dobrovolsky et al. (1979). The thermosphere neutral composition (O/N2) as observed by Global Ultraviolet Imager, across Delhi, during these earthquake events does not show any marked variation. Further, the effect of earthquake events on ionospheric peak electron density is compared to the lower atmosphere meteorological phenomenon of 2015 sudden stratospheric warming event.

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Section: Introductionmentioning

confidence: 99%

Preearthquake anomalous ionospheric signatures observed at low‐mid latitude Indian station, Delhi, during the year 2015 to early 2016: Preliminary results

Gupta

Upadhayaya

2017

JGR Space Physics

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“…In order to search for a possible relation between the ionospheric disturbances and the seismic activities, in this section, we are about to further investigate the spatial characteristics of the ionospheric TEC disturbances. Pulinets and Boyarchuk 13 have suggested that the ionospheric concentration gradually started www.nature.com/scientificreports/ to diminish 5 days before the seismic shock, and a great many studies have shown that the seismo-ionospheric disturbances most likely appear 1-5 days prior to earthquakes 15,18,19,23,26,29,30 . Therefore, in the present analysis it is considered that pre-and post-5 days data are influenced by seismogenic effects.…”

Section: Resultsmentioning

confidence: 99%

“…Nowadays dense and continuous observation has been achieved globally, the International GNSS Service (IGS) has ensured the availability of open access, high-quality GNSS TEC products, IGS Global Ionosphere Map (GIM) TEC data are a superset of data to monitor and study the phenomenon of seismic ionospheric disturbances. Especially in recent years, in order to search for a possible relation between the ionosphere and the seismic activity, based on the GIM-TEC data, more and more statistical analyses with a lot of events have been performed for EQs in some regional areas [16][17][18][19][20][21][22][23][24][25] or global EQs [26][27][28][29][30][31] . However, the pre-earthquake ionospheric disturbances are still challenging and controversial 21,[31][32][33] .…”

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confidence: 99%

Investigation of GIM-TEC disturbances before M ≥ 6.0 inland earthquakes during 2003–2017

Zhu

Jiang

2020

Sci Rep

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With the rapid development of the Global Navigation Satellite System (GNSS) and its wide applications to atmospheric science research, the global ionosphere map (GIM) total electron content (TEC) data are extensively used as a potential tool to detect ionospheric disturbances related to seismic activity and they are frequently used to statistically study the relation between the ionosphere and earthquakes (EQs). Indeed, due to the distribution of ground based GPS receivers is very sparse or absent in large areas of ocean, the GIM-TEC data over oceans are results of interpolation between stations and extrapolation in both space and time, and therefore, they are not suitable for studying the marine EQs. In this paper, based on the GIM-TEC data, a statistical investigation of ionospheric TEC variations of 15 days before and after the 276 M ≥ 6.0 inland EQs is undertaken. After eliminating the interference of geomagnetic activities, the spatial and temporal distributions of the ionospheric TEC disturbances before and after the EQs are investigated and compared. There are no particularly distinct features in the time distribution of the ionospheric TEC disturbances before the inland EQs. However, there are some differences in the spatial distribution, and the biggest difference is precisely in the epicenter area. On the other hand, the occurrence rates of ionospheric TEC disturbances within 5 days before the EQs are overall higher than those after EQs, in addition both of them slightly increase with the earthquake magnitude. These results suggest that the anomalous variations of the GIM-TEC before the EQs might be related to the seismic activities.

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“…These large events have puzzled scientists with pre-seismic signs, which are supposed to forecast the events before they happen. Although some scholars have found electromagnetic signs created from rocks [6][7][8], claiming that they will be detected at the ionosphere [9][10][11], it is still not clear about the propagation mechanism between the Earth's ground and the ionosphere [12,13].…”

Section: Introductionmentioning

confidence: 99%

South Atlantic Anomaly, Ionospheric Signals from Seismic Events

Hagen¹,

Azevedo²

2020

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The purpose of this paper is to analyze the most significant events that occurred in the period 1996-2018 located under the South Atlantic Anomaly (SAA), where the earth's magnetic field is weaker and the trapped particles during the geomagnetic storms suffer decay over time. The time examined corresponds to the Solar Cycles 23 and 24; the area covered is defined by the following coordinates: 0N, −50S, 40E, −90W. Some significant events in this region reported Very Low Frequency (VLF) and Ultra Low Frequency (ULF) waves before the event, varying from minutes, hours, and even weeks before the earthquakes. Our study searches for a mechanism to explain why the crust creates electromagnetic signs detected at the ionosphere. Piezoelectric currents flow on the crust, combining with the magnetic field lines, temporarily producing pre-seismic electromagnetic pulses that are detected at the ionosphere prior to the events. The mechanism that allows electromagnetic signs to be detected at the ionosphere is also elucidated. These signs are brief, and they will cease with the beginning of the shock or shortly thereafter. However, some features contribute to making the signs impossible to detect, involving crust materials, location, magnitude, and depths. We suggest that these ionospheric events could happen for other kinds of hazard events, such as Volcanos.

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Statistical characteristics of seismo-ionospheric GPS TEC disturbances prior to global Mw≥5.0 earthquakes (1998–2014)

Cited by 102 publications

References 34 publications

Preearthquake anomalous ionospheric signatures observed at low‐mid latitude Indian station, Delhi, during the year 2015 to early 2016: Preliminary results

Preearthquake anomalous ionospheric signatures observed at low‐mid latitude Indian station, Delhi, during the year 2015 to early 2016: Preliminary results

Investigation of GIM-TEC disturbances before M ≥ 6.0 inland earthquakes during 2003–2017

South Atlantic Anomaly, Ionospheric Signals from Seismic Events

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