15 March 2023, Volume 37 Issue 1
    

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  • DYNAMICALLY TRIGGERED FAR-FIELD MICROEARTHQUAKES FOLLOWING TAJIKISTAN MS7.4 EARTHQUAKE ON DECEMBER 7,2015
    WEI Yun-yun, WANG Qiong, CHEN Hao, QIAN Cai, XIANG Yuan, ZHANG Lin-lin
    Inland Earthquake. 2023, 37(1): 1-11. https://doi.org/10.16256/j.issn.1001-8956.2023.01.001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on the discrete—wave number method, we calculated the complete Coulomb failure stress (CFS) changes of far field region induced by December 7, 2015 Tajikistan MS7.4 earthquake, and the β statistical value test method is used to analyze the stress triggering effect of strong earthquakes on the seismic activity in the far field. We find that the peak values of dynamic stress change in the remote Kuche, Bachu and Kashi-Wuqia areas are 1.31 MPa, 0.14 MPa and 0.5 MPa, respectively, which have dynamic triggering effect on the microearthquake activities in Kuche and Kashi-Wuqia regions. The results of β statistical value show that, after the MS7.4 earthquake in Tajikistan, the seismicity of Kuche area changed obviously.The maximum dynamic Coulomb stress change caused by the Tajikistan MS7.4 earthquake at the epicenter of the Akto MS6.7 earthquake on November 25, 2016 was 1.0 MPa, indicating that the Akto MS6.7 earthquake was affected by Tajikistan MS7.4 earthquake. Dynamic triggering effect is more obvious. This is consistent with the aforementioned MS7.4 of Tajikistan's promotion of seismic activity in the Kashi-Wuqia confluence area.
  • NEW PROGRESS IN LOW TEMPERATURE THERMOCHRONOLOGY METHODS
    CHEN Jie-yu, WANG Jia-long, LIU Run, HUANG Si-ting, HUANG Wen-bing
    Inland Earthquake. 2023, 37(1): 12-22. https://doi.org/10.16256/j.issn.1001-8956.2023.01.002
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Low temperature thermochronology methods have been widely used in the field of geology, especially the apatite/zircon (U-Th)/He, apatite/zircon fission track (AFT/ZFT) methods, due to closure temperature is low, and it is very sensitive to surface processes such as late Cenozoic tectonic evolution, topographic changes, and geomorphology, volcanic age, etc., and has incomparable advantages over other geochronological methods. With the development of the method, young (~ka) volcanic rocks can be dated accurately. This method has also promoted the upsurge of research on orogenic belt evolution and geomorphological evolution over past decade. It not only calculated exhumation and uplift rate, but also provides basic data for new modeling.
  • CHARACTERISTICS OF SEQUENCE AND ANALYSIS OF ANOMALY BEFORE SHANSHAN MS5.1 EARTHQUAKE, XINJIANG
    GAO Rong, NIE Xiao-hong, LIANG Hui, QIAN Cai, LIU Ping, GAO Ge
    Inland Earthquake. 2023, 37(1): 23-31. https://doi.org/10.16256/j.issn.1001-8956.2023.01.003
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    This paper presents the basic parameters, seismotectonic background, focal mechanism solutions, seismic sequence characteristics, seismicity anomalies and geophysical observation anomalies of Shanshan MS5.1 earthquake. The results are as follows:(1) This earthquake occurred in eastern section of the Tianshan seismic zone, and seismogenic tectonics is the Bolokenu-Aqikekuduk Fault, and focal mechanism solutions is thrust type. (2) The earthquake sequence type is isolated, and the sequence aftershocks are not abundant, with a rapid decay in frequency and intensity. (3) Five seismic activity anomalies existed before the earthquake, namely, MS≥4.0 earthquake calm, MS≥4.0 earthquake enhancement, MS3.0～4.9 earthquake enhancement zone, MS≥3.0 enhancement and MS≥3.0 earthquake belt in the middle part of the Tianshan. (4) Two geophysical observation anomaly exists before the earthquake, which is No.41 well static water level and the rate variation anomaly of the EW component of the Kumish borehole inclinometer.
  • HYDROGEOCHEMICAL CHARACTERISTICS OF SEISMIC UNDERGROUND FLUID MONITORING WELLS (SPRINGS) IN TIANSHAN AREA
    LI Na, GAO Xiao-qi, XIANG Yang
    Inland Earthquake. 2023, 37(1): 32-43. https://doi.org/10.16256/j.issn.1001-8956.2023.01.004
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to study the groundwater chemical characteristics of seismic monitoring wells (springs) in Tianshan area, the groundwater chemical samples of 20 seismic monitoring points in Tianshan fault zone were systematically collected. The hydrochemical and hydrogeochemical characteristics of the monitoring points were discussed by means of hydrogen and oxygen isotopes, Gibbs diagram, ion ratio, Piper three-line diagram, Na-K-Mg triangle diagram and Shukalev classification. The results are as follows : (1) The dominant cation in the water of seismic monitoring wells (springs) in Tianshan area is Na+, and the anions are HCO3-, SO2-4and Cl-, respectively. The TDS is between 249.9-10 272.3 mg·L-1, and most of them are freshwater. (2) The results of δD and δ18O indicate that the water in earthquake monitoring wells (springs) in Tianshan area is mainly from atmospheric precipitation. The Gibbs diagram shows that the groundwater elements in the monitoring points of the study area are mainly controlled by rock leaching, and the groundwater in the monitoring points of South Tianshan and Urumqi is controlled by evaporation and concentration. The ion ratio shows that the dissolution of carbonate and sulfate minerals is the main factor controlling the main ion components of groundwater. (3) The Na-K-Mg triangle diagram shows that the water of seismic monitoring wells (springs) in Tianshan area is mostly “partially balanced water”and “partly immature water”, reflecting that the water-rock reaction is in a more appropriate degree, which is conducive to the transmission of seismogenic information.
  • ANALYSIS FOR EARTHQUAKE EARLY WARNING IN KEY EARLY WARNING AREA IN XINJIANG MIDDLE TIANSHAN MOUNTAINS
    YAN Xin-yi, LI Yan-yong, ZHAO Shi-zhu, CHEN yong
    Inland Earthquake. 2023, 37(1): 44-51. https://doi.org/10.16256/j.issn.1001-8956.2023.01.005
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to complete the quality assessment of early warning results in key early warning areas in the middle part of Tianshan Mountains of Xinjiang, the yield, timeliness, magnitude deviation and epicenter deviation of earthquake early warning systems were analyzed statistically.Based on the analysis of 24 official quick-reported seismic events in the key early-warning area in the middle part of the Tianshan Mountains of Xinjiang from January 1 to August 31, 2022, the first warning results of EEW system and JEEW system in Xinjiang earthquake early warning project were analyzed. The decision system integrated the output results of EEW and JEEW and released them. There were 7 early warning seismic events with timeliness less than 10 s, accounting for 46.7%; the magnitude deviation was 0~0.7, with an average of 0.4; all seismic events with magnitude less than 1.0 accounted for 100%; 14 seismic events with epicenter deviation less than 10km, accounting for 93.3%. By comprehensive analysis, the two sets of earthquake early warning systems in Xinjiang can basically produce early warning results for seismic events above MS3.0 in key early warning areas. The accuracy of the decision system’s release results basically meet the requirements of early warning, and the timeliness of early warning needs to be improved and strengthened.
  • MATHEMATICAL MODELING OF MICRO-SEISMIC SOURCE INVERSION IN MINES WITHOUT VELOCIMETRY
    PANG Cong, LI Cha-wei, MA Wu-gang, JIANG Yong, LIAO Cheng-wang
    Inland Earthquake. 2023, 37(1): 52-59. https://doi.org/10.16256/j.issn.1001-8956.2023.01.006
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The micro-seismic source inversion mathematical model, inversion algorithm and other objects are important sources of micro-seismic source localization errors. To address the situation that the P-wave velocity is easily attenuated and the first wave arrival data pickup error is large, the inversion mathematical model of arrival time difference method (ATDRM) is established based on the arrival time difference model (ATD) and the set of P-wave arrival time equations, and the parameters of P-wave velocity and seismic moment are eliminated from the objective function; meanwhile, the concept of parametric number is introduced to obtain the improved parametric models of L1, L2, L3 and L4, and a series of inversion A series of model comparison experiments and inversion algorithm comparison experiments are designed to comprehensively analyze the superiority of these models. The engineering data show that the overall localization effect of the ATDRM model is better than that of the classical ATD model, and the source error of the ATDRM-L1 model can be reduced by 13.437 0 m. The localization error of the inversion model is influenced by the inversion algorithm, and the monomorphic replacement method has higher localization accuracy and better stability than the genetic algorithm (GA), nonlinear least squares method (NLSM), simulated annealing algorithm (SA) and other methods. The inversion error decreases and then increases with the increase of the parametric parameter N (L1→L4) when the monomorphic substitution method is applied to solve the model; the ATDRM model and its parametric form are valuable for improving the localization accuracy of micro-seismic sources.
  • SPATIALIZATION OF POPULATION AND HOUSING DATA AND ITS APPLICATION IN BAICHENG MS5.4 EARTHQUAKE IN 2021
    ZHAO Jiang-tao, LI Jin-xiang, SUN Jing, HUANG Shuai-tang, MA Jian, ZHANG Feng-fang
    Inland Earthquake. 2023, 37(1): 60-71. https://doi.org/10.16256/j.issn.1001-8956.2023.01.007
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    The rapid assessment of earthquake disaster depends on the accurate number and spatial distribution of population, houses and other facilities in the earthquake area, which is the core support of post-earthquake emergency rescue and earthquake intensity assessment. Based on the residential area and POI data in Aksu region, the population density weight model is constructed by using the method of nuclear density estimation combined with the road distribution and the floor area of houses, and is obtained 1 km×1km of population and housing grid data of the study area. The results show that the linear fitting correlation coefficient between the actual population and the simulated population in each township is 0.909, which is relatively good, indicating that the population spatial results have reached a high accuracy. In order to better verify the above methods and data, take the Baicheng MS5.4 earthquake in 2021 as an example, and analyze the quantitative relationship between the earthquake area population, housing grid data and the seismic assessment area. The simulation of population and housing area has been carried out according to the earthquake assessment area. The error between the data and the actual field data is small, which can meet the needs of rapid post-earthquake disaster assessment, and provide reliable basis and support for disaster pre-assessment and rapid post-earthquake disaster assessment. At the same time, the spatial method also provides a new idea for the follow-up research in this direction.
  • STUDY ON INFLUENCE FACTORS OF HYDROGEN CONCENTRATION AND ANOMALY INFORMATION EXTRACTION METHOD OF KORLA FAULT IN XINJIANG
    YAN Wei, LI Xin-yong, YANG Shao-fu, XU Chang-yin
    Inland Earthquake. 2023, 37(1): 72-79. https://doi.org/10.16256/j.issn.1001-8956.2023.01.008
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    Based on the structural location, lithologic characteristics and observation mode of H2 observation station in Korla fault, Xinjiang, the characteristics of H2 concentration change at observation point and auxiliary air temperature and pressure observation data were analyzed, and the correlation coefficient of H2 concentration change was obtained. The residual data of fault H2 concentration observed since 2014 were obtained by polynomial fitting, and the corresponding relationship between earthquakes and abnormal changes was obtained by combining with the distribution of surrounding historical earthquakes. The results show that: ① Air pressure and temperature have an effect on the concentration of H2 on the fault, showing that the concentration of H2 on the fault is positively correlated with air pressure (correlation coefficient: 0.658 5), and negatively correlated with air temperature (correlation coefficient: -0.795 4). Temperature change has a more significant effect on the concentration of H2. ② The tectonic location and lithology of the hydrogen station on the fault have influence on the morphology of H2 year change. ③ Based on the residual sequence of Savitzky-Golay fitting and the analysis of historical seismic data, it is concluded that there is a significant reaction of H2 concentration before MS≥4.9 earthquakes occurring within 200 km around the observation station, which can provide a reference for the study of seismic conditions.
  • ANALYSIS OF WEATHER AND WATER LEVEL ON URUMQI YUSHUGOU TILT OBSERVATION AND ITS SEISMIC REFLECTION EFFICIENCY TEST
    Mulatijiang Abulaiti, JIN Hua, TENG Hai-tao, MAO Yu-jian
    Inland Earthquake. 2023, 37(1): 80-90. https://doi.org/10.16256/j.issn.1001-8956.2023.01.009
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    Application of wavelet analysis and correlation analysis method, the quantitative study of meteorological elements (temperature, air temperature, air pressure), water level and the elm ditch 4 set of observations, the relationship between the oblique observation instrument and regression equations of each component were obtained by regression analysis, through the original curve and regression residual sequence contrast, summarizes the anomaly characteristics and earthquake cases, The R value scoring method is used to test the seismic reflection efficiency. The results show that: (1) The dominant period of each component of the barometric pressure on the Yushugou tilt observation is 4 069～8 192 min, which is mainly linear in this frequency band; (2) The ground temperature is the main influencing factor of the annual variation information of Yushugou tilt observation (except for the EW direction of horizontal pendulum and the NS direction of borehole tilt), and has a linear relationship with the observation value; (3) Water level is the main influencing factor of the annual variation information of the horizontal pendulum in NS direction and the water pipe gauge in EW direction, and has a linear relationship with the observed value; (4) Regression analysis can effectively eliminate the influence of meteorological factors and water level to a certain extent, and has amplification effect on the identification of seismic anomalies; (5) The result of R-value test shows that the best prediction window of EW component of horizontal pendulum is 270 days, the best R=0.54, R0=0.41, and the best prediction period of NS component of water meter is 340 days, the best R=0.44, R0=0.40, all of which have passed the prediction efficiency test, indicating that they have high abnormal reliability.
  • STUDY ON PRECISE POSITIONING OF EARTHQUAKES IN MIDDLE SECTION OF NORTH TIANSHAN MOUNTAINS
    LI Kui, LIU Li-xia, CAO Chang-jun, ZHANG Qing-yuan
    Inland Earthquake. 2023, 37(1): 91-98. https://doi.org/10.16256/j.issn.1001-8956.2023.01.010
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    In order to explore the main seismogenic structures in the middle section of the North Tianshan Mountains and further define the key monitoring areas, this paper uses the double-difference positioning method to relocate 1 439 seismic events with MS≥1.5 occurred in the middle section of the North Tianshan Mountains from June 2010 to December 2021. The results are as follows: ① Mean value of traveltime residuals changes from -0.22 s to 0.006 6 s, and the average error of source location determination is 1.1 km in east-west direction, 1.4 km in north-south direction, and 2.0 km in vertical depth. ② Earthquakes were mainly distributed in the Urumqi piedmont depression and the southern region, and did not extend to the Junggar basin; The local earthquake epicenter approaches to the tectonic zone, showing a seismic active zone with a strike of nearly 280° and a strike of nearly 300°, which are basically consistent with the southern margin fault zone of Junggar and the Yamat fault zone. ③ According to the depth profile, the dispersion degree of focal depth increases, and it is distributed from 0 to 50 km. Taking Urumqi as the boundary, there are obvious differences in the focal depths of earthquakes on the east and west sides, showing the phenomenon of deep in the east and shallow in the west. Through the precise positioning study of the region, it is proved that the southern margin fault zone of Junggar and the Yamat fault zone are the main seismologic structures in the region, and the earthquakes in the basin-mountain junction are relatively active. Therefore, the southern margin fault zone of Junggar and the Urumqi piedmont depression area will be the key monitoring areas for the earthquake tracking work.
  • CHARACTERISTICS OF SOURCE AND ITS NEIGHBORHOOD POST-EARTHQUAKE TECTONIC STRESS FIELD OF JIASHI MS6.4 EARTHQUAKE IN XINJIANG ON JANUARY 19, 2020
    LEI Xiao-yu, LIU Zhao-cai, ZHAO Peng-bi, WANG Jia-qi, Shamuhaer Yeerken
    Inland Earthquake. 2023, 37(1): 99-105. https://doi.org/10.16256/j.issn.1001-8956.2023.01.011
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Collect the focal mechanism solution data around the Jiashi MS6.4 earthquake in Xinjiang on January 19, 2020 and Keping thrust nappe structure, and use the damped least squares in MSATSI software package to invert the tectonic stress field around the epicenter of the earthquake. The results show that the direction of the principal compressive stress axis in the study area is nearly NS and the overall consistency is good. The maximum principal stress direction in the west section is NNW and the east section is NNE, but the main compressive stress direction in Kashgar, Bachu and other areas near the edge of the Tarim block in the west section is NNE. The direction of the principal compressive stress in the area where the Keping thrust nappe structural belt is located is NNW, and the direction of the principal tensile stress is NNE, which is the same as the direction of the P and T axes of the focal mechanism solution of the earthquake, indicating that the occurrence of the earthquake is affected by the regional tectonic stress field. The overall tension axis in the study area has obvious non-uniformity and wide azimuth distribution, but the main compressive stress axis around the earthquake epicenter has obvious dip angle consistency, which reflects the stress characteristics of the region dominated by thrust.
  • SOFT HARDWARE DESIGN AND IMPLEMENTATION OF EMBEDDED METEOROLOGICAL AUXILIARY OBSERVATION SYSTEM
    LIAN Yin-chao, LI Xiao-dong, YAN Long, SI Qing, YAN Wei
    Inland Earthquake. 2023, 37(1): 106-113. https://doi.org/10.16256/j.issn.1001-8956.2023.01.012
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to enrich the needs of meteorological data in Xinjiang seismic monitoring stations and disaster sites, and make up for the lack of auxiliary observation means in Xinjiang geophysical observation stations and GNSS stations, an embedded meteorological auxiliary observation system is designed and implemented. The system integrates rainfall, temperature, atmospheric pressure, humidity and other direction finding, and has the advantages of low power consumption, low cost, easy operation, portability and strong scalability. It can significantly reduce the cost of the layout of meteorological auxiliary observation network, fill the gap of meteorological auxiliary observation data in Xinjiang regional seismic monitoring stations, and better meet the needs of seismic monitoring for meteorological data by providing continuous and reliable near-point meteorological observation data for earthquake monitoring and prediction personnel and other scientific researchers.
  • DYNAMIC WATER LEVEL ANOMALY REASON SURVEY OF KORLA 43 SPRING IN XINJIANG
    XU Chang-yin, LI Xiao-dong, YAN Wei, YANG Shao-fu, ZHANG Xiao-fei, ZHANG Sen, DONG Min
    Inland Earthquake. 2023, 37(1): 114-120. https://doi.org/10.16256/j.issn.1001-8956.2023.01.013
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    At the beginning of 2019, the dynamic water level of the Korla New 43 Spring changed significantly. Earthquake Agency of Xinjiang Uygur Autonomous Region and the Korla Earthquake Monitoring Center Station carried out a series of investigations and verification to eliminate the influence factors such as observation operation (power supply, data acquisition, sensor error), environment (natural environment and site environment), human interference, and other factors. At the same time, the field soil radon Carbon dioxide and hydrochemical methods are used to analyze the water quality and conduct water plugging experiments and change the water flow direction to determine the cause of the anomaly, and to analyze whether there is correlation between the large amplitude anomaly of dynamic water level and the earthquake precursor anomaly. The investigation and analysis results show that the aging and fracture of underground drainage pipes and the entry of tree roots and grass roots into the cracks are the main reasons for causing a large amount of water accumulation in the spring wells and affecting the large amplitude anomaly of the dynamic water level of the new 43 spring, which eliminates the possibility of earthquake precursor anomalies.
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ISSN 1001-8956　CN 65-1119/P
Administered by: Earthquake Agency of Xinjiang Uygur Autonomous Region
Sponsored by: Earthquake Agency of Xinjiang Uygur Autonomous Region
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