17:15 〜 18:45
[SSS06-P08] The Ionospheric Plasma Perturbations detected by the China Seismo-Electromagnetic Satellite before a Sequence of Strong Earthquakes in 2018
キーワード：earthquake precursor, ionospheric disturbance, the China Seismo-Electromagnetic satellite
The China Seismo-Electromagnetic Satellite (CSES-01), which is also called ZHANGHENG-1, was launched on 2 February 2018, on a sun-synchronous orbit at an altitude of ~507 km with a high orbital inclination of 97.4° and a recursive period of 5 days. The ascending node local time (LT) is fixed at 2:00. The CSES-01 satellite was specially developed to detect the abnormal ionospheric disturbances associated with strong seismic activities. It has eight types of scientific payloads that can observe the ionospheric background environment and perturbations in the electromagnetic waves and field, plasma, and high-energy particles. Among them, the Plasma Analyzer Package (PAP) and Langmuir probe (LAP) were designed to obtain plasma parameters through in-situ detection. The PAP provides ion density (Ni, including hydrogen ion, helium ion, and oxygen ion), ion temperature, and ion drift velocity (Vi). LAP data provides electron density (Ne) and electron temperature (Te), respectively.
From August to October 2018, a series of strong earthquake (EQ) events occurred in southeast Asia and northern Oceania (22°S to 0°N, 115°E to 170°E) within 50 days. We analyze the features of ionospheric plasma perturbations, recorded by the PAP and LAP onboard the CSES-01 satellite, before four EQs with magnitudes of Ms 6.9 to Ms 7.4.
According to long-term data processing and previous analysis results, plasma values vary significantly in different regions, while the disturbance caused by the EQ is relatively small. In addition, considering there is only one satellite, its observation ability is limited in spatial and time resolutions, considering the distance between adjacent tracks in one day is about 2600 km. Therefore, it is not recommended to analyze the seismo-ionospheric disturbances in large areas, which may mix with other disturbance phenomena induced by other factors. In this research, we have monitored the critical areas for a long time, checked the relative abnormal changes of multiple plasma parameters based on the revisiting orbit data (multi-orbit data) by using a quartile analysis method to test and extract the possible seismic anomalies. Moreover, we compared the simultaneous variations of multiple parameters, such as No+, Vz, Ne, Te, and electric field waveform, to ensure the accuracy of seismic anomaly information extraction. In addition, the different variations of No+ and Vz under intense geomagnetic storms and strong EQ were compared.
The results show that within 1 to 15 days before the strong EQs, the No+ and the Ne increased while the Te decreased synchronously. Meanwhile, the Vz significantly increased along the ground-to-space direction. The relative variation of No+ and Vz before the strong EQs are more prominent, and the Vz is not easily influenced by the geomagnetic storm but is susceptible to the seismic activities, which are seemed like promising parameters for analyzing ionospheric disturbances excited by strong seismic activity. Our findings support the possibility of applying in-situ plasma observation of the Low Earth Orbit (LEO) satellites to examine ionospheric pre-EQ signatures, which could be useful to understand seismo-ionospheric precursors better.
Furthermore, China and Italy are jointly building the second satellite, i.e., CSES-02, which will be launched by the end of 2024. CSES-02 will provide almost the same physical field parameters as CSES-01 but with numerous specific optimizations based on CSES-01’s in-orbit performance. More ideal observation results are expected.
From August to October 2018, a series of strong earthquake (EQ) events occurred in southeast Asia and northern Oceania (22°S to 0°N, 115°E to 170°E) within 50 days. We analyze the features of ionospheric plasma perturbations, recorded by the PAP and LAP onboard the CSES-01 satellite, before four EQs with magnitudes of Ms 6.9 to Ms 7.4.
According to long-term data processing and previous analysis results, plasma values vary significantly in different regions, while the disturbance caused by the EQ is relatively small. In addition, considering there is only one satellite, its observation ability is limited in spatial and time resolutions, considering the distance between adjacent tracks in one day is about 2600 km. Therefore, it is not recommended to analyze the seismo-ionospheric disturbances in large areas, which may mix with other disturbance phenomena induced by other factors. In this research, we have monitored the critical areas for a long time, checked the relative abnormal changes of multiple plasma parameters based on the revisiting orbit data (multi-orbit data) by using a quartile analysis method to test and extract the possible seismic anomalies. Moreover, we compared the simultaneous variations of multiple parameters, such as No+, Vz, Ne, Te, and electric field waveform, to ensure the accuracy of seismic anomaly information extraction. In addition, the different variations of No+ and Vz under intense geomagnetic storms and strong EQ were compared.
The results show that within 1 to 15 days before the strong EQs, the No+ and the Ne increased while the Te decreased synchronously. Meanwhile, the Vz significantly increased along the ground-to-space direction. The relative variation of No+ and Vz before the strong EQs are more prominent, and the Vz is not easily influenced by the geomagnetic storm but is susceptible to the seismic activities, which are seemed like promising parameters for analyzing ionospheric disturbances excited by strong seismic activity. Our findings support the possibility of applying in-situ plasma observation of the Low Earth Orbit (LEO) satellites to examine ionospheric pre-EQ signatures, which could be useful to understand seismo-ionospheric precursors better.
Furthermore, China and Italy are jointly building the second satellite, i.e., CSES-02, which will be launched by the end of 2024. CSES-02 will provide almost the same physical field parameters as CSES-01 but with numerous specific optimizations based on CSES-01’s in-orbit performance. More ideal observation results are expected.