# EPP

### 地球与行星物理

ISSN  2096-3955

CN  10-1502/P

Citation: Wen, Y. Z., Tao, D., Wang, G. X., Zong, J. Y., Cao, J. B., Battiston, R., ZeRen, Z. M., and Shen, X. H. (2022). Ionospheric TEC and plasma anomalies possibly associated with the 14 July 2019 Mw7.2 Indonesia Laiwui earthquake, from analysis of GPS and CSES data. Earth Planet. Phys., 6(4), 313–328. http://doi.org/10.26464/epp2022028

2022, 6(4): 313-328.

SPACE PHYSICS: IONOSPHERIC PHYSICS

## Ionospheric TEC and plasma anomalies possibly associated with the 14 July 2019 Mw7.2 Indonesia Laiwui earthquake, from analysis of GPS and CSES data

 1 Key Laboratory of Earth Exploration and Information Techniques of Ministry of Education, Chengdu University of Technology, Chengdu 610059, China 2 School of Geophysics, Chengdu University of Technology, Chengdu 610059, China 3 School of Space and Environment, Beihang University, Beijing 100191, China 4 Dipartimento di Fisica, Università di Trento, Trento 38123, Italy 5 Trento Institute for Fundamental Physics and Applications (TIFPA), National Institute for Nuclear Physics (INFN), Trento 34136, Italy 6 National Institute of Natural Hazards, Ministry of Emergency Management of China, Beijing 100085, China

Corresponding author: Dan Tao, dan.tao@cdut.edu.cn

Web Publishing Date: 2022-06-06

This study presents signatures of seismo-ionospheric perturbations possibly related to the 14 July 2019 ${M}_{w}$7.2 Laiwui earthquake, detected by a cross-validation analysis of total electron content (TEC) data of the global ionospheric map (GIM) from GPS and plasma parameter data recorded by the China Seismo-Electromagnetic Satellite (CSES). After separating pre-seismic ionospheric phenomena from the ionospheric disturbances due to the magnetospheric and solar activities, we have identified three positive temporal anomalies, around the epicenter, at 1 day, 3 days and 8 days before the earthquake (14 July 2019), along with a negative anomaly 6 days after the earthquake. These results agree well with the TEC spatial variations in latitude–longitude–time (LLT) maps. To confirm these anomalies further, we employed the moving mean method (MMM) to analyze ionospheric plasma parameters (electron, ${\mathrm{O}}^{+}$and ${\mathrm{H}\mathrm{e}}^{+}$densities) recorded by the Langmuir probe (LAP) and Plasma Analyzer Package (PAP) onboard the CSES. The analysis detected on, on Day Two, Day Four, and Day Seven before the earthquake, remarkable enhancements along the orbits around when in proximity to the epicenter. To make the investigations still more convincing, we compared the orbits on which anomalous readings were recorded to their corresponding four nearest revisiting orbits; the comparison did indeed indicate the existence of plasma parameter anomalies that appear to be associated with the Laiwui earthquake. All these results illustrate that the unusual ionospheric perturbations detected through GPS and CSES data are possibly associated with the ${M}_{w}7.2$ Laiwui earthquake, which suggests that at least some earthquakes may be predicted by alertness to pre-seismic ionospheric anomalies over regions known to be at seismic risk. This case study also contributes additional information of value to our understanding of lithosphere–atmosphere–ionosphere coupling.