Ionospheric total electron content disturbance associated with May 12, 2008, Wenchuan earthquake

Abstract

Global positioning system (GPS) Total electron content (TEC) Wenchuan earthquake Global ionospheric map (GIM) COSMIC f 0 F2 Crustal Movement Observation Network of China (CMONOC) a b s t r a c t Possible ionospheric disturbances relating to the May 12, 2008, Ms8.0 Wenchuan earthquake were identified by Global Positioning System (GPS)-derived total electron content (TEC), ionosonde observations, the global ionospheric map (GIM), and electron density profiles detected by the Constellation Observation System for Meteorology Ionosphere and Climate (COSMIC).We applied a statistical test to detect anomalous TEC signals and found that a unique enhancement in TEC, recorded at 16 GPS stations, appeared on May 9, 2008. The critical frequency at F2 peak (f 0 F2), observed by the Chinese ionosondes, and maximal plasma frequency, derived from COSMIC data, revealed a characteristic similar to GPS TEC variations. The GIM showed that the anomalous variations of May 9 were located southeast of the epicenter. Using GPS data from 13 stations near the epicenter, we analyzed the TEC variations of satellite orbit traces during 04:00e11:00 UT. We found that TEC decreased to the east and increased to the southeast of the epicenter during this period. Results showed that the abnormal disturbance on May 9 was probably an ionospheric precursor of the Wenchuan earthquake of May 12, 2008.

Ionospheric Precursors Observed in TEC Due to Earthquake of Tamenglong on 3 January 2016

“…The presence of precursor in GPS-TEC data was reported earlier [6][7][8] . However the magnitude of perturbation varied from case to case depending on the magnitude of earthquake and the distance of the observing station from the epicentre.…”

“…In recent years due to the advent of global positioning system (GPS), total electron content (TEC) of ionosphere has become an important parameter and is widely used to observe the seismo-ionospheric anomaly. Reported results show positive as well as negative perturbations in TEC 3,[6][7][8] . Emitted radon gas may ionize atmospheric constituents, whereas seismic originated electric field may cause plasma drift by E  B force.…”

“…The opposite effects on TEC perturbations are attributed to change in the current/electric field direction in moving from east to west with respect to the geomagnetic meridian of the epicentre, which in turn affects the movement of the E  B plasma drift. Using ground and satellite-based measurements, anomalous changes starting from ground up to ionospheric levels for numerous earthquakes have been reported by several workers [5][6][7][8]19,[26][27][28] . These studies show strong changes in various parameters on the surface and in the atmosphere/ionosphere a few days prior to the main shock of the earthquakes and provide strong evidences of lithosphere-atmosphere-ionosphere coupling.…”

Ionospheric anomalies preceding the low-latitude earthquake that occurred on April 16, 2016 in Ecuador

“…The search for earthquake precursors in the ionosphere is a very active field of research (e.g. Liu et al, 2004;Zakharenkova et al, 2006Zakharenkova et al, , 2008Zhao et al, 2008;Mubarak et al, 2009;Zhu et al, 2010;Zou and Zhao, 2010;Yao et al, 2012;Zhu et al, 2013;Wang et al, 2014;Xinzhi et al, 2014;Li et al, 2015;Guo et al, 2015;Pundhir et al, 2015;Alcay, 2016). There are studies that for example concentrate on a particular earthquake and through the employment of different techniques, they are able to identify ionospheric anomalies that appear a few days before and which are associated to an earthquake.…”

“…There are studies that for example concentrate on a particular earthquake and through the employment of different techniques, they are able to identify ionospheric anomalies that appear a few days before and which are associated to an earthquake. For instance, the M w 7.9 earthquake that happened in the county of Wenchuan, China (31.0°N 103.4°E) has drawn a lot of attention in regards to the observations of seismo-ionospheric signatures (Zhao et al, 2008;Li et al, , 2015Liu et al, 2009;Zhou et al, 2009;Zhu et al, 2010;Ma and Wu, 2012). Initially, Zhou et al (2009) detected 9, 6 and 3 days before this earthquake ionospheric disturbances considered as precursors of the incident.…”