This paper analyzes the characteristics of time sequence changes of gravity points near the epicenter,different changes of measuring lines and gravity changes of measuring areas in point-line-area manner respectively ...This paper analyzes the characteristics of time sequence changes of gravity points near the epicenter,different changes of measuring lines and gravity changes of measuring areas in point-line-area manner respectively with the 5-period mobile gravity data through densified observation by the South Xinjiang Observation Network after the 2015-2016 Akto earthquake in Xinjiang. The gravity observation results before the earthquake indicate that the Wuqia-Bulungkol area near the epicenter presented the trend of gravity value increasing since 2015,but the gravity value decreased half a year before the earthquake,and witnessed a high gradient zone of gravity changes during some periods before the earthquake. The gravity observation results after the earthquake show that there is a trend of opposite changes in gravity difference on the northern and southern sides of Bulunkou,and good correspondence exists between the characteristics of gravity field changes near the epicenter before and after the earthquake and the geologic structure distribution in the area.展开更多
In this study,data from the Xinjiang regional network and IRIS shared global stations are used to relocate the Akto MS6. 7 earthquake sequence on November 25,2016 by using double difference location method. Three eart...In this study,data from the Xinjiang regional network and IRIS shared global stations are used to relocate the Akto MS6. 7 earthquake sequence on November 25,2016 by using double difference location method. Three earthquakes of MS4. 8,MS6. 7 and MS5. 0 are inverted by using the g CAP method,and the focal mechanism solutions are obtained.According to the results of relocating,the location of the main shock is 39. 22°N,73. 98°E,the distribution of the earthquake sequence is about 70 km in length,and the focal depth is mainly within the range of 5-20 km. The plane and depth profiles of the earthquake sequence show that aftershocks extended in SEE direction after the main shock and the dip angle of fault plane is steep. Focal mechanism results show that the three earthquakes are characterized by strike-slip movement. Based on the results of field geological investigation,it is inferred that the seismogenic fault of the Akto earthquake is Muji fault,which is located at the northernmost end of the Kongur extensional system.The possible cause of this earthquake is that the Indian Plate continues to push northward,and during this compression process,the Indian Plate is affected by the clockwise rotation of the Tarim basin,which causes the accumulation of right-lateral action of the Muji fault,resulting in this earthquake.展开更多
The Akto MS6. 7 earthquake occurred near the western end of the Muji fault basin in the top of the Pamir syntaxis. The main shock of this earthquake is complicated and the focal mechanism solutions based on the seismi...The Akto MS6. 7 earthquake occurred near the western end of the Muji fault basin in the top of the Pamir syntaxis. The main shock of this earthquake is complicated and the focal mechanism solutions based on the seismic wave inversions are different. Based on the Sentinel-1 SAR data,the coseismal deformation field of the earthquake is obtained by In SAR technique. Based on the elastic half-space dislocation model,the geometrical parameters and the slip distribution model are determined by nonlinear and linear inversion algorithms. The results show that the distributed slip model can well explain the coseismic deformation field. The earthquake includes at least two rupture events,which are located at 7 km(74. 11°E,39. 25°N)and 33 km(74. 49°E,39. 16°N)east from the epicenter according to the CENC. The deformation field caused by the earthquake shows a symmetry distribution,with the maximum LOS deformation of 20 cm. The main seismic slip is concentrated in the 0-20 km depth,and the maximum slip is 0. 84 m. The seismic fault is the Muji fault,and this earthquake indicates that the northeastward push of the Indian plate is enhanced.展开更多
The relationship between gravity variation and the Akto Ms6.7 earthquake on November 11, 2016, was studied by use of mobile gravity observation data from the China continental structural environmental monitoring netwo...The relationship between gravity variation and the Akto Ms6.7 earthquake on November 11, 2016, was studied by use of mobile gravity observation data from the China continental structural environmental monitoring network. The result revealed that before the Akto earthquake, a high positive gravity variation was observed in the Pamir tectonic knots region （within a maximum magnitude of approximately ＋80 microgal）, which was consistent with the existing knowledge of gravity abnormality and the locations of strong earthquakes. In view of the recent strong seismic activities in the Pamir tectonic knots region, as well as the strong upward crust movement and compressive strain, it is believed that gravity change in the Pamir tectonic knots region reflects the recent strong seismic activities and crust movement.展开更多
基金the NaturalScience Foundation of Xinjiang Uygur Autonomous Region(2016D01A062)Seismic Situation Tracking and Orientation Tasks(2016010218,2017010204)+2 种基金Earthquake Science Foundation of Xinjiang(201613,201612)the National Natural Science Foundation of China(41474016,41374030)Earthquake Science and Technology Spark Plan(XH16042Y,XH17044)
文摘This paper analyzes the characteristics of time sequence changes of gravity points near the epicenter,different changes of measuring lines and gravity changes of measuring areas in point-line-area manner respectively with the 5-period mobile gravity data through densified observation by the South Xinjiang Observation Network after the 2015-2016 Akto earthquake in Xinjiang. The gravity observation results before the earthquake indicate that the Wuqia-Bulungkol area near the epicenter presented the trend of gravity value increasing since 2015,but the gravity value decreased half a year before the earthquake,and witnessed a high gradient zone of gravity changes during some periods before the earthquake. The gravity observation results after the earthquake show that there is a trend of opposite changes in gravity difference on the northern and southern sides of Bulunkou,and good correspondence exists between the characteristics of gravity field changes near the epicenter before and after the earthquake and the geologic structure distribution in the area.
基金Co-sponsored by the Seismological Science and Technology Spark Program(XH19053)the Regular Project “Operation and Maintenance of the National Automatic Reporting Center(CSN/GSN)and System Optimization”
文摘In this study,data from the Xinjiang regional network and IRIS shared global stations are used to relocate the Akto MS6. 7 earthquake sequence on November 25,2016 by using double difference location method. Three earthquakes of MS4. 8,MS6. 7 and MS5. 0 are inverted by using the g CAP method,and the focal mechanism solutions are obtained.According to the results of relocating,the location of the main shock is 39. 22°N,73. 98°E,the distribution of the earthquake sequence is about 70 km in length,and the focal depth is mainly within the range of 5-20 km. The plane and depth profiles of the earthquake sequence show that aftershocks extended in SEE direction after the main shock and the dip angle of fault plane is steep. Focal mechanism results show that the three earthquakes are characterized by strike-slip movement. Based on the results of field geological investigation,it is inferred that the seismogenic fault of the Akto earthquake is Muji fault,which is located at the northernmost end of the Kongur extensional system.The possible cause of this earthquake is that the Indian Plate continues to push northward,and during this compression process,the Indian Plate is affected by the clockwise rotation of the Tarim basin,which causes the accumulation of right-lateral action of the Muji fault,resulting in this earthquake.
基金sponsored by the National Natural Science Foundation of China(41874017)Seismological Spark Program(XH17059)
文摘The Akto MS6. 7 earthquake occurred near the western end of the Muji fault basin in the top of the Pamir syntaxis. The main shock of this earthquake is complicated and the focal mechanism solutions based on the seismic wave inversions are different. Based on the Sentinel-1 SAR data,the coseismal deformation field of the earthquake is obtained by In SAR technique. Based on the elastic half-space dislocation model,the geometrical parameters and the slip distribution model are determined by nonlinear and linear inversion algorithms. The results show that the distributed slip model can well explain the coseismic deformation field. The earthquake includes at least two rupture events,which are located at 7 km(74. 11°E,39. 25°N)and 33 km(74. 49°E,39. 16°N)east from the epicenter according to the CENC. The deformation field caused by the earthquake shows a symmetry distribution,with the maximum LOS deformation of 20 cm. The main seismic slip is concentrated in the 0-20 km depth,and the maximum slip is 0. 84 m. The seismic fault is the Muji fault,and this earthquake indicates that the northeastward push of the Indian plate is enhanced.
基金jointly supported by the the special earthquake research grant offered by the China Earthquake Administration(201508009,201308009)the Director Foundation of Institute of Seismology,China Earthquake Administration(IS201326121)
文摘The relationship between gravity variation and the Akto Ms6.7 earthquake on November 11, 2016, was studied by use of mobile gravity observation data from the China continental structural environmental monitoring network. The result revealed that before the Akto earthquake, a high positive gravity variation was observed in the Pamir tectonic knots region （within a maximum magnitude of approximately ＋80 microgal）, which was consistent with the existing knowledge of gravity abnormality and the locations of strong earthquakes. In view of the recent strong seismic activities in the Pamir tectonic knots region, as well as the strong upward crust movement and compressive strain, it is believed that gravity change in the Pamir tectonic knots region reflects the recent strong seismic activities and crust movement.
