## 4 Discussion  
Geomagnetic polarization anomalies are generally considered to be caused by electromagnetic radiation due to fault creep or rock rupture in the pre-earthquake source areas [22], which implies that multiple areas may experience fault creep or rock rupture simultaneously prior to an earthquake. According to the results of [PERSON] et al. [23], the pre-earthquake regional stresses will appear to be concentrated at multiple points, and there is likely to be a similar connection between multiple strong earthquakes across the region or a strong earthquake sequence (e.g., [23]). The strong earthquakes in western mainland China discussed above are mainly distributed in the Qinghai-Tibet Plateau (i.e., Tibetan Plateau) and surrounding areas, and the occurrence of multiple earthquakes within a short period of time in the aforementioned areas may have the same tectonic genesis. The collision between the Indian and Eurasian plates led to the rapid uplift of the Tibetan Plateau, and the strong tectonic shifts have continued until the present time, resulting in strong seismic activity within and around the Tibetan Plateau [24]. The subsequent seismogenesis of multiple polarized high-value zones occurring simultaneously depends on the development of each gestation terrestrial body. Based on the solid-body earthquake gestation model [25], the areas can gradually accumulate a large amount of elastic potential energy during the slow relative plate motion. The high-speed block zones with solid-body properties and the ring-shaped distribution of a certain range of seismic activity enhancement zones on their periphery are caused by the higher rupture intensity of the source zone than the surrounding medium (e.g., [26; 27]), and this difference also leads to the difference in electromagnetic radiation intensities. From 1 January 2018 to 21 May 2021, only one Mw 4.9 earthquake occurred on 2 October 2019, in Tongren, Guizhou within the region of high geomagnetic vertical intensity polarization on 15 October 2020, and no Mw > 4 magnitude earthquake occurred in the rest of the region; from 3 October 2019 to 21 May 2021, no > Mw 4.0 earthquake occurred in the region, while the periphery of the high-value region, especially the periphery of the southwest boundary, had a higher concentration of seismic activity. In fact, 10 earthquakes of Mw > 4.0 occurred in the region during the 3 years from 1 January 2015 to 31 December 2017, including the Jiuzhaigou Mw 7.0 earthquake and two Mw > 5.0 earthquakes, which indicates that a more significant seismic calm occurred in the region from 3.5 to 1.5 years before the earthquake, which is in line with the characteristics of the solid-body that the peripheral areas rupture earlier than the solid-body interior (e.g., [28; 29; 30]). [PERSON] et al. [31] summarized the characteristics of seismic activity before strong earthquakes occurred and concluded that the long axis of the gestation void area appeared from 370 to 780 km and 1-7 years before the earthquake, which agrees with the anomalous area counted in this study of 3-288 \(\times\) 10\({}^{4}\) km\({}^{2}\) and the circle diameter of 196-1970 km. The results of geomagnetic sounding indicated that the main source and aftershock body of the Made earthquake is in the junction area between the high conductivity of the middle and lower crust and the high-resistance body in the upper part [32]; similar results were obtained from studies in the eastern section of the East Kunlun and Longmenshan Fault Zones. These studies imply that strong earthquakes mostly occur near the significant electrical boundary zone at the block boundary, and this region is also the area where remarkable differences in electromagnetic radiation characteristics occur. The difference in the medium physical properties between and outside the seismogenic zones can last for a certain period. The reason why electromagnetic anomalies can be extracted only at specific times may be due to the limitation of the data processing level.