| Sichuan-Yunnan region is located in the eastern boundary of the Qinghai-Tibet Plateau,where geological structure is complex and strong earthquakes occur frequently.Strong and frequent earthquake disasters will not only directly damage the safety of human life and property,but also possibly cause secondary damage to human beings by triggering landslides,debris flows and other secondary disasters.Therefore,it is of great significance to analyze the time symmetry characteristics of active blocks and earthquake disasters from the perspective of blocks,and to study the relationship between earthquakes in different blocks and related factors such as earth rotation,sunspot activity,etc.for realizing the precise docking of active blocks and seismic trend judgement.In this paper,the spatial distribution characteristics of earthquakes in Sichuan-Yunnan region are analyzed by using the method of nuclear density estimation,the temporal symmetry characteristics of earthquakes in different active blocks are analyzed by using the commensurability method,the relationship between seismic events in different active blocks and the relative number of sunspots is analyzed by using the phase method and correlation analysis method,and the polar symmetric mode decomposition method and correlation analysis method are used to analyze the relationship between seismic events and the relative number of sunspots in different active blocks.The relationship between the earthquake and the rotation rate of the earth in different active blocks is discussed.The main conclusions are as follows:(1)The earthquakes of Ms?6.3 in Sichuan-Yunnan block are likely to occur in 2025 or 2027 in the west of 101.1°E and south of 31.20 N.Judging by the trend of time symmetry,the results show that the earthquakes Ms?6.3 in Sichuan-Yunnan block are most likely to occur in 2027 and 2035 on an annual scale,followed by 2021,November 2025 on a monthly scale,and September 5,2022 on a daily scale.From the statistical law of earthquakes and sunspots,the earthquakes in Sichuan-Yunnan block mostly occur in the sunspot facies.The logarithmic extreme year is near and the descending section,while 2025 and 2027 are near the peak year and descending section of sunspot relative number respectively,so the possibility of earthquakes occurring in these two years is greater.The relationship between earthquakes and earth rotation shows that the possibility of earthquakes occurring in Sichuan-Yunnan block during the deceleration and acceleration periods of the seasonal variation is relatively close.Therefore,earthquakes may occur in November 2025.In terms of spatial symmetry,the epicenter latitude position of Sichuan-Yunnan block shows the characteristics of "three southward and two northward migrations",and the epicenter longitude shows the characteristics of "two identical and one different".Therefore,earthquakes of Ms?6.3 in Sichuan-Yunnan block may occur in the north in 2025 or 2027.(2)The Ms?6.4 earthquakes in the southwestern Yunnan block are more likely to occur in the west of 102.6° E and north of 23.0°N on July 29,2019 or 2028.Judging by the trend of time symmetry,the results show that the earthquakes Ms?6.4 in the southwestern Yunnan block are most likely to occur in 2028 on an annual scale,next in 2019 and 2020,most likely in August 2028 and August 2033 on a monthly scale,next in October 2020,and most likely on a daily scale,on August 16,2021 and July 29,2028.According to the statistical law of sunspot,the occurrence of earthquakes in the southwestern Yunnan block is more likely near the valley year of the relative sunspot number and the downward section,while in the valley year and the downward section of the sunspot period in 2019 and 2028,respectively,the occurrence of earthquakes in these two years is more likely.The relationship between earthquakes and the rotation of the Earth shows that the earthquakes in the southwestern Yunnan block occur in the seasonal acceleration period of the rotation rate of the earth.The probability of earthquake occurrence is obviously higher than that of deceleration period,so the probability of earthquake occurrence in July 2028 is higher.The time distribution of earthquake occurrence in southwestern Yunnan block shows that the probability of earthquake occurrence in the second half of each month is higher.In terms of spatial symmetry,the epicenter latitude of the southwestern Yunnan block shows the characteristics of "3 identical and 2 different",and the epicenter longitude shows the migration rule of "2 east,1 west" or "2 west,1 east".Therefore,the Ms?6.4 earthquake in the southwestern Yunnan block may occur in the central region in 2019 or July 29,2028.(3)The Ms?6.5 earthquake in Bayankara block is more likely to occur in the west of 101.8°E and south of 32.8°N in March 2019 or 2032.Judging by the trend of time symmetry,the results show that the Ms?6.5 earthquake in the Bayan Hara Block is most likely to occur in 2026 on an annual scale,next in 2019 and 2020,most likely in July 2019,March 2032 on a monthly scale,and next in August 2022,most likely in a daily scale on January 19,2020.According to the statistical law of earthquakes and sunspots,the Bayan Hara Block is most likely to occur on a daily scale.Earthquakes mostly occur in the vicinity of the solar sunspot relative extreme year,and in 2019 and 2032 are just near the valley year of the solar sunspot cycle,so the possibility of earthquakes occurring in these two years is relatively high.The relationship between earthquakes and earth rotation shows that the frequency of earthquakes occurring in the deceleration period of seasonal variation of the earth's rotation rate is obviously higher than that in the acceleration period,so the possibility of earthquakes occurring in March 2032 is obvious.In terms of spatial symmetry,the epicenter latitude and longitude of the Bayan Kara block earthquakes show the characteristics of "two identical and one different",while the epicenter longitude shows the characteristics of "three identical and two different".Therefore,the Ms?6,5 earthquake in the Bayan Kara block may occur in the southern region in March 2019 and 2032.(4)There are differences in the correlation between the earthquakes in Sichuan-Yunnan block,southwestern Yunnan block,Bayankara block and the relative number of sunspots.The Ms?6.3 earthquakes in Sichuan-Yunnan block mostly occur in the vicinity of the solar sunspot relative extreme year and the downward section,and mainly occur in the two-week solar sunspot activity;the Ms?6.4 earthquakes in southwestern Yunnan block are more likely to occur in the vicinity and downward section of the solar sunspot relative valley year;the Ms?6.5 earthquakes in Bayankara block are at the solar sunspot relative extreme.The probability of occurrence near the year of duty is higher than that at the rising and falling stages,and the probability of occurrence near the peak year of sunspot relative number is the highest.(5)On different time scales,there are also obvious differences in seismic and earth rotation rates between Sichuan-Yunnan block,southwestern Yunnan block and Bayankara block.The Ms?6.3 earthquakes in Sichuan-Yunnan block and Ms?6.4 in southwestern Yunnan block are more likely to occur in the year of accelerated change of the earth's rotation rate,while the Ms?6.5 earthquakes in Bayankara block are more likely to occur in the year of decelerated change of the earth's rotation rate.The Ms?6.3 earthquakes in Sichuan-Yunnan Block and Ms?6.5 earthquakes in Bayankara Block are more likely to occur in the deceleration month of seasonal variation of the earth's rotation rate.The possibility of accelerating the occurrence of the Ms?6.4 earthquakes in southwestern Yunnan Block is obviously higher than that of deceleration month in seasonal variation of the earth's rotation rate.The month in which Ms?6.3 earthquakes is less likely to occur are June-August and October in Sichuan-Yunnan block,the month in which Ms?6.4 earthquakes is less likely to occur are January,September and December in southwestern Yunnan block,the month in which Ms?6.5 earthquakes is less likely to occur are June,October and December in in Bayankara block. |
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