Studying Wushi M_W7.0 earthquake on January 23,2024 is the key to understanding the seismogenic structure in this area. The slip distribution of Wushi earthquake is inverted by using InSAR technology and distributed slip model. The results show that the seismogenic fault is Maidan fault, and the seismogenic fault is dominated by thrust type and has a small amount of left-lateral strike-slip component. The strike is 230°, the dip angle is 48°, the maximum slip is 2.23 m, the moment magnitude is M_W6.99, and the motion mode of the earthquake is thrust earthquake. The static Coulomb stress caused by the earthquake shows that the near-field area along the fault strike direction at both ends of the north and south is a dangerous area for future moderate-strong earthquakes.

A total of 813 instrument intensity information and 496 sets of strong motion records of Wushi 7.1 earthquake were obtained by Xinjiang Seismic Network Center. The peak acceleration of PH002 station was 280.68 cm·s^-2, which was the maximum peak acceleration obtained this time.This paper compares the attenuation relationship between the peak accelerations obtained from 219 stations and the fifth generation of China Seismic Ground Motion Parameter Zoning Map, and finds that the two are more consistent within a range of 100 km.This paper calculates and analyzes 5 peak accelerations exceeding 100 cm·s^-2. The acceleration response spectrum of these 5 stations was compared and analyzed with the seismic design response spectrum. At the same time, the effective seismic duration of these 5 stations was calculated, and it was found that the seismic energy release was faster within 200 km, indicating a greater seismic destructive force.

In order to explore the applicability of RST algorithm in the extraction of seismic thermal infrared anomalies in Xinjiang region, the MODIS land surface temperature data set of Wushi M_S7.1 earthquake was constructed, and after removing the pixel-by-pixel time series trend of the data set, RST algorithm was used to extract the surface temperature anomaly information of Wushi M_S7.1 earthquake. The results show that the change process of surface temperature anomaly in Wushi M_S7.1 earthquake can be divided into six stages: emergence-disappearance-reappearance-expansion-maximum-disappearance; The abnormal area of surface temperature of Wushi M_S7.1 earthquake is distributed along the strike of tectonic zone. Wushi M_S7.1 earthquake occurred 99 days after the maximum surface temperature anomaly. It is feasible to extract seismic thermal infrared anomaly by combining MODIS data with RST algorithm in relevant research of Xinjiang region.

In order to study the temporal and spatial variation of Wushi M_S7.1 earthquake sequence and the characteristics of the source parameters, the results show that the aftershocks are mainly distributed on the northeast and southwest sides of the main shock, and the distribution is basically consistent with the strike of the Maidan fault. The current sequence b value is 0.67, h value is 1.3, and p value is 1.28. The focal mechanism solution is thrust type, the stress drop is at a low level, and the sequence attenuation is basically normal. The earthquake is a mainshock-aftershock type, and the largest aftershock is M_S5.8 earthquake.

Wushi M_S7.1 earthquake is the first earthquake above M7 since the completion of the national earthquake intensity rapid report and early warning project. In order to improve the ability to prevent and mitigate earthquake risk, the construction of earthquake intensity rapid report and early warning project is put in place. The magnitude, epicentral location and focal depth results of the real-time output of early warning are compared with the official rapid report results of the National Network Center, and the instrument intensity output error is analyzed. The results show that the national early warning network can still demonstrate stable, reliable and efficient earthquake early warning and intensity rapid reporting capabilities in the case of severe epicenter deviation.

In order to further study Wushi M_S7.1 earthquake, double-difference seismic position method was used to relocate the seismic sequence, and the positioning results showed that: ① after relocation, the spatial position of the mainshock did not change much. It was 2 km away from the position before relocation, and the depth was 25.6 km, which was deeper than that before relocation. ② After reposition, earthquake sequence had a tendency to develop southward along the Maidan fault, which was basically consistent with the distribution characteristics of disasters.③ When the Maidan fault was extruded by the piedmont extrusion, it was stopped near the epicenter of the mainshock, and the seismic structure of the Wushi section of the Maidan fault was deeper than that of the Aheqi section, and the activity was relatively weak, so there were more and shallow aftershocks in the SW direction and fewer and deeper aftershocks in the NE direction in the mainshock epicenter.

After Wushi M_S7.1 earthquake occurred on January 23,2024, the seismic intensity map was drawn according to the post-earthquake damage survey results, combined with the remote sensing image, focal mechanism and seismogenic structure of the earthquake area. In the process of drawing the intensity map, the IX degree is located in the mountainous area and lacks the layout of the strong earthquake network. Therefore, the InSAR results are referred to for the first time when determining the IX degree intensity circle. By comparing the results of earthquake damage investigation and instrument intensity results, it is found that the two are in good agreement, so the instrument results are referred to when determining the boundary of the intensity circle. This study focuses on the destruction of various types of houses in different intensity areas and the phenomenon of earthquake geological disasters, and analyzes and determines the characteristics of various types of house damage.

Based on the observation data of Xinjiang Seismic Network, Wushi M_S7.1 earthquake sequence on January 23,2024 is analyzed. The results show that the aftershock activity of Wushi earthquake sequence is rich and the frequency attenuation is fast. Based on the historical earthquake sequence analogy, sequence parameters (b value, p value, h value), waiting time, magnitude difference and energy ratio, Wushi M_S7.1 earthquake sequence is judged as the main shock-aftershock type. From the early qualitative determination of historical earthquake sequence types to the tracking and determination of Wushi M_S7.1 earthquake sequence types by quantitative calculation of earthquake sequence parameters, it has certain reference function for the tracking and determination of earthquake sequence types.

In order to study the response changes of water levels in New 55 and New 46 wells caused by Wushi M_S7.1 earthquake, the co-seismic response characteristics of water levels in observation wells were compared and analyzed, and the co-seismic response mechanism was discussed from the changes of aquifer permeability and seismic wave energy density. The results show that: 1 The co-seismic response of Jiashi New 55 well and Wushi New 46 well is mainly characterized by the rapid rise of well water level. The results of solid tide calculation and analysis show that when the seismic wave acts on New 55 well and New 46 well, the vertical hydraulic exchange of the former is enhanced, the horizontal hydraulic exchange is weakened, and the water in the aquifer is exchanged with the well water, causing the co-seismic rise of the well water level. The permeability of the latter aquifer increases, and the aquifer water exchanges with the well water, causing the co-seismic rise of the well water level. The calculation results of seismic energy density show that New 55 well is easier to trigger the co-seismic response than New 46 well, and this differential response may be related to the lithology of the well aquifer.

Through the field geological and geomorphological survey and trench excavation of the Danghe nanshan fault,it is found that multi-level fault scarps are developed along the north side of the fault, and the latest scarps break the floodplain of the gully, while the west section of the fault is accompanied by fold activity; The geological exploration trench excavated at the mouth of Dahonggou gully shows that the fault has dislocated a relatively new gravel layer. The sample test results show that the latest active age of the fault is at least the middle Holocene; Two trenches revealed the same seismic event, which occurred after (4.69±0.40) ka BP.

The seismic risk assessment of off-site roads in water conservancy and hydropower projects plays an important role in the implementation progress of the project. Road outside the engineering field in Sichuan-Yunnan area is taken as the research object, and the fuzzy set theory and the judgment matrix method are used to establish a comprehensive evaluation mathematical model of the damage of the two major factors of geological environment and seismic risk, and to analyze the possibility of road damage after the earthquake in 37 prefectures and cities. The analysis shows that the road outside the project site in Sichuan-Yunnan area is more likely to suffer from moderate earthquake damage, and the index of earthquake risk damage to the road outside the project site in Sichuan is higher than the earthquake risk assessment value in Yunnan.

On July 20,2022, an M_S4.8 earthquake occurred in Changji, Xinjiang. The Xinjiang earthquake early warning system is in the test operation stage. The early warning results of the earthquake event are output, and the data are only internally referenced. Comprehensive analysis of the early warning results of the event (JEEW, FJEEW and fusion system output), compared with the official earthquake rapid report results of the China Earthquake Networks Center, the first report of the JEEW system takes 7.1 s, the magnitude deviation is -0.7, and the epicenter deviation is 3.3 km. The triggering time of the first report of the FJEEW system is 7.5 s, the magnitude deviation is -1.1, and the epicenter deviation is 3.4 km. The first report of the early warning fusion system was released 7.8 s after the earthquake, the magnitude deviation was -0.7, and the epicenter deviation was 3.3 km. The magnitude and epicenter of the three sets of earthquake early warning systems were in good agreement. For this earthquake event, the accuracy of the timeliness, magnitude and epicenter results of the earthquake early warning system meets the requirements of construction goal.

The focal mechanism solution of M_S≥4.0 earthquake in Wushi M_S7.1 earthquake sequence is calculated by P-wave first motion method. The focal mechanism solution has the characteristics of good consistency in the early stage and disordered consistency in the later stage. In space, the type of focal mechanism solution in Wushi County is mostly thrust type, and the type of focal mechanism solution in Aheqi County is mostly strike-slip type. The frequency spectrum of M_S≥5.0 earthquake sequence in Wushi M_S7.1 earthquake sequence is calculated by using the digital waveform data of Xinjiang seismic network and the fast Fourier transform method. The calculation results show that the frequency spectrum of the M_S≥5.0 aftershocks in Wushi County has the characteristics of spectrum migration in the early stage, and the frequency band of the last M_S≥5.0 earthquake becomes wider, and the frequency spectrum migration characteristics disappear. The 5-magnitude aftershocks in Aheqi County all showed spectral migration characteristics.

Based on the retrospective analysis of the observation data of five geoelectric stations in Xinjiang before the Wushi M_S7.1 earthquake on January 23,2024, the geoelectric dominant azimuth of each station before the earthquake is calculated, and the data variation characteristics are summarized. It is found that the geoelectric dominant azimuth of each station before the earthquake has different degrees of abnormal changes, and the anomalies are characterized by dispersion, concentration, deflection and jump. The geoelectric dominant azimuth anomalies of Wushi and Wenquan stations near the epicenter have quasi-synchronous changes in time. Before the earthquake, the Wushi, Wenquan and Hetian stations within 500 km of the epicenter not only had quasi-synchronous decline in the correlation coefficient between different azimuths, but also had similar linear polarization enhancement in the polarization azimuth, and the abnormal changes of the dominant azimuth of Wushi and Hetian stations showed the phenomenon of concentration to the principal compressive stress P, indicating that the changes of geoelectric data observed by Wushi, Wenquan and Hetian stations before the Wushi M_S7.1 earthquake had a certain mechanism connection with the earthquake.

This article is based on the constitutive relationship of rock stress. The tilt and ground strain data in the pre earthquake and surrounding 500 km range of the Wushi M_S7.1 earthquake on January 23, 2024 were used as the “response variables”. The Coulomb stress triggered model’s loading unloading response ratio method was used to calculate. The results showed that the Ush cave body strain and other three measurement items all showed pre earthquake LURR anomalies, indicating a significant stress accumulation process in the source area medium. At the same time, it also indicates that the tilt and Effective information for earthquake prediction can be extracted from the tidal frequency band of strain.

In order to study the consistency of data obtained by different observation methods at the same station and the same physical quantity, the horizontal pendulum and vertical pendulum of the hot spring old station are selected as the research objects to study the consistency of observation data and the response characteristics of interference anomalies in different frequency bands. The analysis results show that the observation data of horizontal pendulum and vertical pendulum of hot spring are stable and accurate, the solid tide record is clear, and there is strong consistency in the same direction of semi-diurnal wave and daily wave frequency bands. From the minute value to the tidal frequency band, the observation data of the horizontal pendulum and the vertical pendulum of the hot spring are inconsistent, and the observation data mainly contain their own attribute information ; in the annual periodic frequency band, the phase difference between the horizontal pendulum and the vertical pendulum in the EW direction is about 41 days. The phase difference in NS direction is about 14 days, and the phase lags behind the temperature. Considering the phase lag, the horizontal pendulum and vertical pendulum observations of hot springs are in good agreement, and both are linearly related to the temperature. Therefore, the temperature is the main influencing factor of the annual periodic frequency band of the horizontal pendulum and vertical pendulum of hot springs

Using the time series of GPS continuous observation stations in Xinjiang as the data source, Hilbert Yellow transform (HHT) was used to capture the microdynamic anomaly changes of ground surface displacement in the short and medium term before the M6 or above earthquake in Xinjiang. Taking the M_S6.6 Jinghe earthquake on August 9, 2017 in the North Tianshan Seismic belt as an example, through the source mechanism solution, baseline time series and HHT single time series analysis, the HHT filter frequency band is 3.858 0×10^-7~6.430 0×10^-8Hz (period 30-180 days). Some short-term precursor anomalies and seismogenic information were extracted 40 days before the earthquake. Using this frequency band, the Aketao M_S6.7 earthquake on November 25,2016 in Xinjiang was analyzed. About 55 days before the earthquake, the amplitude, amplitude coherence function value and correlation coefficient of the two related stations near the epicenter showed micro-dynamic changes of displacement significantly higher than the background level. Two seismic events show that it is possible to extract valuable micro-dynamic characteristics of pre-seismic displacement and earthquake preparation information from GPS continuous observation data in a one-year time scale, which provides a reference for earthquake trend analysis.

Based on New 09 spring, New 10 spring and New 15 spring with water radon concentration of 20 000～100 000 Bq·m^-3, the standard instrument transfer calibration experiment was carried out by using the international scale reference device Alpha GUARD radon measuring instrument and its water radon measuring component. The relative errors of calibration K values were 3.60%, -0.81% and 2.09%, respectively. The comparison between the experimental results and the calibration results of radon gas solid source shows that the water samples with water radon concentration above 20 000 Bq·m^-3 can be tested by the new calibration method of standard instrument, and the use of spring water with different water radon concentration will not affect the accuracy of the calibration results. The Alpha GUARD radon measuring instrument can be used as a standard instrument to calibrate the FD-125 radon and thorium analyzer by using the daily monitoring spring with high radon concentration in the Xinjiang Seismic Underground Fluid Comprehensive Station, so as to replace the calibration of solid radon source. This study provides data support for the operation technical regulations and promotion trial of the new calibration method for radon observation in seismic monitoring.

For the determination of the focal depth of moderately strong earthquakes, the teleseismic converted wave depth phase pP and sP sounding is an effective method, and the depth accuracy can reach 2 km when the depth phase is clear. Teleseis program is used to fit the theoretical seismogram of the Maduo M_S7.4 earthquake, and compared with the actual observation. The focal depth of the earthquake is measured, and the influence of the crustal velocity model on the teleseismic body wave depth phase pP sounding is analyzed and discussed. The results show that the initial rupture depth of the Maduo earthquake is 12 km, and the uncertainty of the V_p in the velocity model has a greater influence on the arrival time of the seismic phase in the theoretical seismogram.

Collect 130 destructive earthquake events with intensity data from 1716 to 2022, supplement the recent destructive earthquake intensity data in Xinjiang, and classify 124 seismic intensity maps and 281 pairs of intensity circle long and short axis data. The mathematical method is used to fit the seismic intensity attenuation model of different time nodes and different focal mechanisms in Xinjiang. It is found that in the process of intensity attenuation, strike-slip and reverse-fault earthquakes are slightly different. Different seismic source rupture properties will affect the long and short axes of intensity attenuation relationship. Therefore, we can use it as a correction factor to quickly evaluate the intensity influence field of earthquake disasters. After the earthquake occurs, the long and short axis data of the intensity circle can be modified and improved to evaluate more accurately.

The instrument used to measure radon in the underground fluid chamber of the Geophysical Observation Center of Earthquake Agency of Xinjiang Uygur Autonomous Region is FD-125, which was purchased in 1979. Due to the serious aging of the instrument for a long time, there is no spare instrument and no manufacturer to replace it. If the instrument fails to be repaired in time and there is a lack of spare observation instruments, it will cause data disconnection and affect the overall scientific quality of observation data. Therefore, in this paper, the water sample of Shuimogou 15 spring in Xinjiang is taken as the measurement object, and the DDL-2 radon detector is introduced to detect and compare with the FD-125 radon detector under the same environmental conditions. The results show that the DDL-2 radon monitor has stable performance and small fluctuation range of measured values, which can meet the requirements of precursory observation specifications and correctly reflect the change of radon content in groundwater. It is considered that the DDL-2 radon monitor has the potential to replace the FD-125 radon monitor as the daily measurement instrument of water radon.

On January 19,2020, the Jiashi M_S 6.4 earthquake occurred near the Keping nappe in the west of the southern Tianshan Mountains in Xinjiang. The analysis of the Keping ground resistivity observation data at 169 km from the epicenter shows that since October 2017, the two-component ground resistivity observation values of the Keping station have shown obvious abnormal rate changes. The NS-direction abnormal change range is -2.33%, and the EW-direction is -0.72%. At the same time, the two components showed anisotropic changes, and the anisotropy S decreased rapidly. In order to explore whether there is a mechanical mechanism between the Keping ground resistivity anomaly and the Jiashi M_S 6.4 earthquake, this paper calculates the distribution of stress and strain in the observation point area before the earthquake by the fault virtual dislocation model, and combines the P-axis direction calculated by the focal mechanism solution. It is found that the abnormal change of Keping ground resistivity before the earthquake is related to the earthquake.

In depth analysis of the activity characteristics, sequence parameters, and sequence types of the Wushi M_S7.1 earthquake sequence on January 23, 2024 shows that the aftershock sequence of the Wushi M_S7.1 earthquake is rich, and the intensity of seismic activity decays slowly, showing a fluctuating attenuation characteristic; The overall attenuation of earthquake frequency is relatively fast. The aftershocks are mainly distributed at the junction of the basin and mountains, with a length of about 200 km and a width of about 150 km, and are generally distributed in the NE direction. Before 4 strong aftershocks with M_S＞5.5, there was a certain degree of low p-values and h-values. Based on the analysis of the energy release ratio, b-value, and the difference in magnitude between the main shock and the maximum aftershock of the largest earthquake in the sequence, the Wushi M_S7.1 earthquake sequence on January 23, 2024 belongs to the main shock aftershock type.

Observation data of three sets of VP broadband vertical pendulum tiltmeter at Korla station, Ruoqiang station and Qiemo station are selected, and the seismic noise level in the seismic frequency band is calculated by using the power spectral density analysis method. The results show that the background noise level of the instrument at Korla station is low due to the excellent observation conditions of the cavern and the small interference of the observation environment around the cavern. The noise level of the three sets of VP-type broadband vertical pendulum tiltmeter does not show obvious regularity in spatial distribution, but it shows the consistency that the NS component record is better than the EW component.

Deformation observation located on the interface of each circle and layer has not only the information from the stress accumulation inside the earth,but also the influence of various factors outside the earth,which has rich connotation of mathematics and physics.Based on the characteristics of comprehensiveness and separability of deformation measurement value series,this paper analyzes Wenquan boday strain,air temperature,water level and air pressure in frequency domain,decomposes the time series value,and studies the influencing factors of different frequency bands of wenquan body strain. The results show that (1) influence of air pressure on the body strain of wenquan mainly has two frequency bands: Monthly wave between 2～4 hours and 1～2 months; (2) The main factor affecting the annual periodic frequency band of wenquan body strain is the water level,and the phase lags behind the water level by about 29 days; (3) The influence factor of daily wave and semidiurnal wave band of Wenquan body strain is solid tide.

Based on the measured shear wave velocity data of 260 boreholes in Weinan City, the relationship between shear wave velocity and depth of common soil types in this area is statistically regressed according to the site category by using the first-order function, second-order polynomial and third-order polynomial models. By comparing the goodness of fit, the optimal fitting regression relationship is the third-order polynomial model. The prediction accuracy of the optimal model is verified by comparing the predicted wave velocity of the reserved borehole with the measured shear wave velocity. At the same time, the influence of rock and soil types and site types on the prediction accuracy of the model is studied. The results show that distinguishing lithology and classifying site types can reduce the relative error of the predicted wave velocity to a certain extent and improve the prediction accuracy of the model. Taking loess and silty clay as examples, the predicted values of wave velocity obtained by the recommended model and the literature model of the same loess site are compared. It shows that the statistical relationship model between shear wave velocity and soil depth has obvious regional characteristics, and the type and depth of rock and soil also have certain influence on the regional adaptability of the model. When the measured data of shear wave velocity cannot be obtained in practical work, the statistical model of the region should be preferred.

In order to provide direct and objective measurement for the scientific analysis of blasting effect, the monitoring data are obtained comprehensively and truly by using seismic professional instruments, and the factors related to blasting effect are found out, and the risk prevention measures are put forward. Starting from the key parameters such as blasting vibration velocity, energy attenuation and dominant frequency, the H/V spectral ratio method is used to evaluate the influence of site response. The blasting magnitude is used to verify and check the blasting energy, and the energy attenuation law in this area is obtained by fitting. The energy distribution and dominant frequency law are obtained by waveform time-frequency analysis. Through the monitoring and analysis of mine blasting, it is concluded that the blasting energy, intensity, velocity and acceleration decrease with the increase of distance. The intensity increases with height on different floors of the same building; The maximum vibration speed recorded by the instrument is lower than that specified in Blasting Safety Regulations; Blasting has little effect on the earthquake damage of the surrounding buildings, but it is necessary to consider the long-term impact of blasting vibration on the self-built brick and earth house, and the long-term impact on the decoration and external tiles of the brick and concrete house. The monitoring test shows that it is feasible to develop the method of seismic effect monitoring and impact analysis of blasting, and the results can be used to guide mine safety production.

Based on the existing four-dimensional disaster volume mode, this study applied and analyzed the model by incorporating factors related to earthquake disasters. The disaster volume index of destructive earthquakes in Xinjiang from 2002 to 2022 was calculated to further classify disaster levels. To verify the accuracy of the model, the calculated results were compared with the results of a previously established three-dimensional disaster volume mode, and the disaster losses of the Wenchuan and Tangshan earthquakes, as well as other earthquakes, were calculated. The research results showed that under the consideration of richer disaster information, the calculation results of this model were more accurate and matched the actual situation of disaster losses.

Using 131 destructive seismic events with intensity data, a total of 322 pairs of long and short axis data of intensity circle, the attenuation relationship of seismic intensity in different regions of Xinjiang is fitted by mathematical method. The seismic intensity attenuation models used in Xinjiang region are collected and sorted out. The long and short axis radii of each intensity zone of Wushi M_S7.1 earthquake on January 23,2024 are simulated and calculated by using the model, and the absolute error analysis is carried out with the long and short axis radii of the actual survey intensity. The high intensity area of this earthquake is more than 40% larger than the high intensity area of the same magnitude in the past. The calculation results in the VII degree area are the closest to the actual value. The error in the long axis direction of the VI degree area is small, and the error in the short axis direction of the VI degree area is large. The intensity attenuation relationship used in the past may have a small epicenter distance in the high intensity area, and there is a large epicenter distance in the low intensity area. Therefore, when the intensity attenuation relationship is used to quickly evaluate the intensity impact field of earthquake disasters, special attention should be paid to the method of limiting the head and tail of the attenuation relationship to more accurately evaluate.

To improve the earthquake monitoring equipment operations and maintenance security system construction, form operations personnel unified command, unified equipment management, unified scheduling, equipment operations efficient equipment support mechanism, improve the earthquake equipment operational response speed and the ability to solve practical problems, this paper is based on the cloud platform, use to server architecture design to realize the seismic equipment operational security system. Starting from the actual operation and maintenance of seismic equipment, the system strives to solve the deficiencies of poor management efficiency and low timeliness of operation and maintenance in the current operation and maintenance work, and realizes the digitization of troubleshooting, equipment management, data archiving and other functions of regional operation and maintenance work, which provides feasible reference for improving and supplementing the construction of regional operation and maintenance support system of seismic instruments and equipment.

The seismic data recorded by ultra-wideband seismometer JCZ-1T of Chengdu Earthquake Monitoring Center Station were studied, and it was found that there were low-frequency and long-period fluctuation in the data. The comparative analysis between the sluice experiment of hydropower station and the real-time waveform in the period of low-frequency long-period fluctuation proves that there is a direct correlation between the long-period fluctuation and the flushing operation of Hydropower Station., and it is obtained from the experiment that the two important factors affecting the shape change of low-frequency long-period waveform are the sluice time and the sluice scale respectively. According to the experimental results, it is considered that the low-frequency and long-period fluctuation reflects the “oscillation” process in which the water level and water flow rate change sharply and gradually return to calm during sluice.

Using the mobile gravity observation data after Wushi M_S7.1 earthquake in the South Tianshan area,the gravity field changes in the South Tianshan area before and after Wushi M_S7.1 earthquake were obtained,and the 1-year and multi-year scale gravity changes before and after the earthquake in the area were studied. The results show that after the Wushi earthquake,the zero isoline of gravity change passes through the epicenter area and a high gradient zone of gravity change appears. In the area where the zero contour of gravity change appears,the material density is undergoing a transition process of increasing and decreasing. The difference in material increase and decrease leads to strong movement and energy accumulation. The gravity anomaly before strong earthquakes may last for a long time,and there may be a small change in the gravity field. Therefore,when extracting and analyzing the gravity anomaly signal before strong earthquakes,it is necessary to consider the gravity observation data with a long time span. The mobile gravity data observed after the earthquake can better reflect the stress release characteristics of the seismogenic fault,which is helpful to analyze the development trend of aftershocks.

Before the M6.4 earthquake inYangbi, Yunnan on May 21, 2021, the comprehensive probability values of the comprehensive prediction scheme of the M_S≥5.0 earthquake in western Yunnan and the comprehensive probability values of the comprehensive prediction scheme of the M_S≥6.0 earthquake in Yunnan breaking through the prediction threshold on January 28, 2021 and March 17, 2021 respectively, reaching the medium-term prediction index and meeting the first conditions of the prediction. Mercury and solid carbon dioxide in Xiaguan have also breaking through the forecast threshold, and the necessary conditions have been met. According to the hierarchical early warning model, the comprehensive prediction scheme of M_S≥5.0 earthquake in western Yunnan and the comprehensive prediction scheme of M_S≥6.0 earthquake in Yunnan have the conditions for short-term prediction on January 28, 2021 and March 17, 2021 respectively. Yangbi M_S6.4 earthquake occurred on May 21, 2021 after 3.8 months and 2.1 months respectively.When both comprehensive schemes reach the short-term prediction index, the risk of M_S≥6.0 strong earthquake in western Yunnan is enhanced.

By analyzing the characteristics of underground fluid anomalies and focal mechanism solutions before Changji M_S4.8 earthquake on July 20,2022,the characteristics and distribution range of underground fluid anomalies before the earthquake were summarized.The analysis shows that the underground fluid anomaly of the Changji earthquake is within 80~140 km.From the perspective of the time from the earthquake,the underground fluid anomalies before the Changji earthquake can be divided into short-term anomalies and medium-term trend background anomalies, of which short-term anomalies are the main ones.Background anomaly of the medium-term trend shows that the dynamic water level of Xin 26 Spring decreases first and then increases.The short-term and impending anomalies are manifested as the rise of static water level in Xin 04 Well, the rise of static water level in Xin 20 Well and the rise of conductivity in Xin 15 Spring.The anomaly shows an EW distribution in space.The focal mechanism solution results show that the nodal plane I strikes 81°, the dip angle is 69°, and the slip angle is 174°.The nodal plane II has a strike of 173°, an inclination of 84°, and a sliding angle of 21°.The P-axis orientation is 305°, and the T-axis orientation is 39°, indicating that Changji M_S4.8 earthquake was an earthquake event under the stress of NWW compression and NEE extension.The direction of the main compressive stress obtained from the focal mechanism solution of Changji earthquake is the same as that of anomaly distribution before the earthquake.

Through five different pumping depth experiments at the depth of 5~105 cm at the Aksu fault hydrogen observation point in Xinjiang, it can be seen that there are great differences in the hydrogen background value, daily amplitude and dynamic characteristics of different pumping depths in the fault hydrogen observation.Due to the strong penetrability and low viscosity of hydrogen diffusion, hydrogen has obvious uneven zonality in the vertical direction of the observation hole. And because of the difference in the structural position of the observation point and the influence of meteorological factors, the hydrogen background value and the quality of the observation data are different. The pumping depth of 80 cm in the hanging wall of the fault at Aksu observation point, the mean square error and coefficient of variation of fault hydrogen data are significantly better than other depths, which can be used as the preferred depth of Aksu fault hydrogen observation.

Zemuhe fault zone, serving as a common boundary between the Daliangshan sub-block and the Chuan-dian rhombohedral block, connects the active southeastern Tibetan Plateau with the stable Southern China block, and recent research indicates an increasing risk of strong earthquakes along this fault zone. The seismic deformation characteristics and stress distribution state of the southern section of the Zemuhe fault zone are quantitatively analyzed in this paper, utilizing newly established continuous GNSS observation data in the near field along with published regional GNSS observation data since 2017. By obtaining the interseismic motion field, we invert kinematic parameters of faults based on a double fault dislocation model. The results reveal that slip rates of the southern Zemuhe fault zone is 3.57±0.47 mm/yr and of the southern Daliangshan fault zone is 5.05±0.47 mm/yr. The near-field data of the newly constructed Zemuhe fault zone exerts a significant influence on the precision of model estimation, thereby substantially enhancing the resolution of the double-fault dislocation model. The strain rate results show that the principal strain rate direction of the eastern boundary of the Sichuan-Yunnan block is characterized by SW-NE stretching and NW-SE squeezing. The southern section of the Zemuhe fault zone presents a higher stress state, with the tensile strain rate being higher than the compressive strain rate, with the average magnitude of 41 nstrain/yr and 27 nstrain/yr, respectively, and is in the high gradient zone of the maximum shear strain rate, with the average magnitude of 28~40 nstrain/yr, indicating significant stress and energy accumulation.

Weizhou Island is located about 37 km south of Beihai City, Guangxi Province. It is the youngest Quaternary volcanic island in China. The island has two volcanic eruptions, Nanwan Volcano and Daling Volcano. The study shows that the two volcanoes have similar eruption processes: the early stage is a phreatomagmatic explosive eruption, the middle stage is a magmatic explosive eruption, and the late stage is a phreatomagmatic explosive eruption. The Nanwan fire has the characteristics of migration, and the last eruption age is the late Late Pleistocene. The eruption time of Daling volcano is later than 33 ka. In this paper, the risk probability map of volcanic ash disaster in Weizhou Island is completed. The results show that the volcanic ash produced by explosive eruption of magma will affect Weizhou Island and its surrounding 30 km range, and has little impact on other areas.

As an affected area of the 1605 Qiongzhou M712 earthquake, Dongzhai Port's subsidence deformation holds significant importance for studying land subsidence processes and urban planning in Haikou. This study utilizes fiber Bragg grating (FBG) borehole displacement monitoring technology to analyze vertical displacement data from seven boreholes over two years, determining current subsidence rates and investigating influencing factors. Key findings include: (1) Displacement rates at seven boreholes range from -8.40 mm/a to 18.78 mm/a, with average subsidence and uplift rates of -3.10 mm/a and 4.42 mm/a respectively. (2) Deformation exhibits distinct vertical stratification, primarily concentrated in shallow subsurface layers, potentially explaining the limited surface deformation observed. (3) Subsidence rates show positive correlation with stratum bearing capacity, indicating tectonic activity as the dominant control mechanism, while geological processes like sand liquefaction and soft soil creep appear less influential. (4) The tectonic framework reveals differential movement patterns: subsidence within the Dongzhai Port graben contrasts with uplift in adjacent horsts, spatially consistent with structural controls from the Puqian-Qinglan fault system.

Using the continuous gravity data observation data of Xinjiang Wushi station, analyze the change of power spectral density with time, calculate the vertical displacement of the double frequency microseisms, and combine with the Ardhuin seismic spectra model(ASSM) to explore the influencing factors that may affect the double frequency microseism, The results show that the anomalous change of the double frequency microseism before the Jiashi M_S6.4 earthquake is not affected by the typhoon, waves and meteorological factors, and it may be a pre-seismic perturbation of the earthquake. The study of the double frequency microseism characteristics will have implications for earthquake forecasting.

To clarify the primary influencing factors in different frequency bands of the strain measurement data from the Jinping seismic station, the Fast Fourier Transform (FFT) method was applied to analyze the spectral characteristics of the NS/EW components of the strain meter and temperature and pressure observation sequences. The results indicate:① significant in-phase features were observed in the annual, daily, semi-diurnal, and high-frequency bands among the three; ② the NS component in the 2⁶～2⁷ min frequency band and the EW component in the 2⁶～2⁸ min frequency band exhibited strong linear correlation with pressure; ③ solid tidal effects were clearly identified in the observation data, validating the stability and reliability of the data; ④ temperature was the dominant factor in the annual frequency band, with phase lags of 77 days for the NS component and 71 days for the EW component. After phase correction, the two components exhibited a significant linear relationship. Additionally, the roles of interference factors and their physical mechanisms at different frequency bands were explored, providing theoretical foundations for preprocessing deformation observation data and interpreting geophysical signals.