Lithosphere–Atmosphere–Ionosphere Coupling Effects Based on Multiparameter Precursor Observations for February–March 2021 Earthquakes (M~7) in the Offshore of Tohoku Area of Japan

Geosciences

卷:11

Shih-Sian Yang¹  Masashi Hayakawa²  Jun Izutsu³  Ekaterina Budilova⁴  Maria Solovieva⁵  Alexander Schekotov⁵ 

[1] Department of Space Science and Engineering, National Central University, 300 Jhongha Rd., Jhongli District, Taoyuan 32001, Taiwan;

[2] Hayakawa Institute of Seismo Electromagnetics, Co., Ltd. (Hi-SEM), UEC (University of Electro-Communications) Alliance Center 521, 1-1-1 Kojima-cho, Chofu, Tokyo 182-0026, Japan;

[3] International Digital Earth Applied Science Research Center, Chubu University, 1200 Matsumoto-cho, Aichi, Kasugai 487-8501, Japan;

[4] Kamchatka Branch of Geophysical Survey of Russian Academy of Sciences, 683006 Petropavlovsk-Kamchatsky, Russia;

[5] The Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, 10-1 Gruzinskaya, 123242 Moscow, Russia;

关键词: earthquake (EQ) precursors;    lithosphere–atmosphere–ionosphere coupling (LAIC);    multiparameter observation;    ULF/ELF/VLF data;    atmospheric gravity waves;    global ionosphere map (GIM) total electron content (TEC) data;   

DOI  :  10.3390/geosciences11110481

来源: DOAJ

【 摘 要 】

The purpose of this paper is to discuss the lithosphere–atmosphere–ionosphere coupling (LAIC) effects with the use of multiparameter precursor observations for two successive Japanese earthquakes (EQs) (with a magnitude of around 7) in February and March 2021, respectively, considering a seemingly significant difference in seismological and geological hypocenter conditions for those EQs. The second March EQ is very similar to the famous 2011 Tohoku EQ in the sense that those EQs took place at the seabed of the subducting plate, while the first February EQ happened within the subducting plate, not at the seabed. Multiparameter observation is a powerful tool for the study of the LAIC process, and we studied the following observables over a 3-month period (January to March): (i) ULF data (lithospheric radiation and ULF depression phenomenon); (ii) ULF/ELF atmospheric electromagnetic radiation; (iii) atmospheric gravity wave (AGW) activity in the stratosphere, extracted from satellite temperature data; (iv) subionospheric VLF/LF propagation data; and (v) GPS TECs (total electron contents). In contrast to our initial expectation of different responses of anomalies to the two EQs, we found no such conspicuous differences of electromagnetic anomalies between the two EQs, but showed quite similar anomaly responses for the two EQs. It is definite that atmospheric ULF/ELF radiation and ULF depression as lower ionospheric perturbation are most likely signatures of precursors to both EQs, and most importantly, all electromagnetic anomalies are concentrated in the period of about 1 week–9 days before the EQ to the EQ day. There seems to exist a chain of LAIC process (cause-and-effect relationship) for the first EQ, while all of the observed anomalies seem to occur nearly synchronously in time for the send EQ. Even though we tried to discuss possible LAIC channels, we cannot come to any definite conclusion about which coupling channel is plausible for each EQ.

【 授权许可】

Unknown