The 2008 Nura Mw6.7 earthquake occurred in front of the Trans-Alai Range, central Asia. We present Interferometric Synthetic Aperture Radar （InSAR） measurements of its coseismic ground deformation that are available...The 2008 Nura Mw6.7 earthquake occurred in front of the Trans-Alai Range, central Asia. We present Interferometric Synthetic Aperture Radar （InSAR） measurements of its coseismic ground deformation that are available for a major earthquake in the region. Analysis of the InSAR data shows that the earthquake ruptured a secondary fault of the Main Pamir Thrust for about 20 kin. The fault plane striking N46~E and dipping 48~SE is dominated by thrust slip up to 3 m, most of which is confined to the uppermost 2-5 km of the crust, similar to the nearby 1974 MwT.0 Markansu earthquake. The elastic model of interseismic deformation constrained by GPS measurements suggests that the two earthquakes may have resulted from the failures of two high-angle reverse faults that are about 10 km apart and rooted in a locked dScollement at depths of 5-6 kin. The elastic strain is built up by a freely creeping decollement at about 16 mm/a.展开更多
The April 20, 2013, Ms7.0 Lushan earthquake was successfully recorded by closely spaced Continuous Global Positioning System （CGPS） stations owned by the Crustal Movement Observation Network of Chi- na （CMONC）. Th...The April 20, 2013, Ms7.0 Lushan earthquake was successfully recorded by closely spaced Continuous Global Positioning System （CGPS） stations owned by the Crustal Movement Observation Network of Chi- na （CMONC）. The 1-Hz GNSS data from eight CGPS stations, which are located between 30 km and 200 km from the hypocenter, were processed within quasi-real-time. The near-field surface deformation indicated the following characteristics ： the near-field movements were limited to several centimeters ; the peak of the deformation wave was significantly larger than the static permanent offset; at the beginning of the event, the north wall of the fault moved to the southeast as the south wall moved to the southwest ; station SCTQ, which was the closest station to the hypocenter at 30 km, had the largest static permanent displacement of 2 cm; the peaks of the deformation waves were 1.5 cm, 5 cm and 3 cm, to the east, the south and vertically upward, respectively ; and the peaks of velocity and acceleration, derived from the deformation, were 3.4 cm/s and 5.3 cm/s^2,respectively.展开更多
Co-seismic ground-surface deformation of the Yushu earthquake on April 14, 2010 is studied on the basis of interferometry principle by using InSAR images from ALOS PALSAR and ENVISAT ASAR pairs. The observed maximum l...Co-seismic ground-surface deformation of the Yushu earthquake on April 14, 2010 is studied on the basis of interferometry principle by using InSAR images from ALOS PALSAR and ENVISAT ASAR pairs. The observed maximum line-of-sight displacement is 54 cm, which is equivalent to a sinistral strike slip of 180 cm on the surface. The location of macro-epicenter is very close to the epicenter determined by in situ investigation, suggesting that InSAR is an ideal tool for quick identification of the macro-epicenter, and thus for timely disaster assessment after a destructive earthquake.展开更多
The Underground Gas Storage( UGS) in Hutubi( HTB),Xinjiang is the largest gas storage reservoir in China and it has significance for coordinating the gas supply and demand relationship,peak-load regulation,implementat...The Underground Gas Storage( UGS) in Hutubi( HTB),Xinjiang is the largest gas storage reservoir in China and it has significance for coordinating the gas supply and demand relationship,peak-load regulation,implementation of strategic reserves,national security, and social economic sustainable development. Therefore, the deformation monitoring and simulation analysis of UGS operation has important technical support and reference value for the stability and safe operation of the underground gas storage. In this paper,we use the elevation data obtained from 7 periods of second-order leveling surveys in the Hutubi underground gas storage area in 2013- 2015 to analyze the influence of gas well pressure on the vertical deformation of the underground gas storage reservoir.Research has shown that the absolute vertical subsidence rate is approximately in the range from 11. 8mm to 16. 1mm and the relative subsidence change is about 4. 3mm,near the surface deformation of Hutubi underground gas storage area except for the annual subsidence rate of- 2. 86 mm by the basic influence of uplift of the Tianshan Mountains.Groundwater over-extraction in the Hutubi area also has an impact on the vertical variation of the surface in this region. The land surface change per unit pressure of gas storage has an impact of about 0. 625mm- 1. 125 mm. 17 scenes Terra SAR-X radar images acquired from August,2013 to August,2014 are exploited by Small Baseline Subset( SBAS) In SAR method to obtain the surface deformation time series during the operation of UGS in Hutubi,meanwhile combined with the pressure data of injection / productionwells,the multi-point source Mogi model is used to simulate the UGS deformation field in Hutubi. The results show that the deformation characteristics of the whole UGS area is a discontinuous distribution with the peak deformation value of 10 mm and- 8mm in the satellite line of sight( LOS) during gas injection and production,respectively and the retrieved deformation sequences correspond very well to the gas injection / production pressure changes. Based on the multi- point source Mogi model, we simulate the deformation process of UGS,HTB,and with the adaptive forward search method,the radius and depth of point source are obtained. The simulated results indicate that when the average injection / production pressure of UGS,HTB is 18 MPa and 15 MPa, LOS deformation is up to 7mm and- 4mm,respectively,and surface deformation is related to the density of gas injection( production) wells. The UGS gas distribution is not uniform,indicating that the structure of underground gas storage is complex. Thus using a more elaborate geomechanical model and other deformation observation data will be helpful for better simulating the UGS internal structure and explaining the mechanism of deformation.展开更多
The deformation responses of surface cap rocks of Underground Gas Storage( UGS) in Hutubi,Xinjiang during gas injection and production were investigated with the GPS data recorded by the deformation monitoring network...The deformation responses of surface cap rocks of Underground Gas Storage( UGS) in Hutubi,Xinjiang during gas injection and production were investigated with the GPS data recorded by the deformation monitoring network,which includes 13 observation sites. The time series of three-dimensional deformation of the surface cap rocks was obtained in the UGS operation process,and the deformation signals in different phases were identified by combining the GPS data with wellhead pressure data. The results show that the respiration response of surface cap rock deformation is obvious during gas injection and production of UGS,and the surface deformation due to a 1MPa change of wellhead pressure is 1. 02 mm in gas injection and 1. 24 mm in gas production horizontally, and- 1. 11 mm in gas injection and 0. 86 mm in gas production vertically.展开更多
A linked-fault-element model is employed to invert for contemporary slip rates along major active faults in the Sichuan-Yunnan region (96°-108°E, 21°-35°N) using the least squares method. The model...A linked-fault-element model is employed to invert for contemporary slip rates along major active faults in the Sichuan-Yunnan region (96°-108°E, 21°-35°N) using the least squares method. The model is based on known fault geometry, and constrained by a GPS-derived horizontal velocity field. Our results support a model attributing the eastward extrusion of the Tibetan Plateau driven mainly by the north-northeastward indentation of the Indian plate into Tibet and the gravitational collapse of the plateau. Resisted by a relatively stable south China block, materials of the Sichuan-Yunnan region rotate clockwise around the eastern Himalayan tectonic syntaxis. During the process the Garzê-Yushu, Xianshuihe, Anninghe, Zemuhe, Daliangshan, and Xiaojiang faults, the southwest extension of the Xiaojiang fault, and the Daluo-Jinghong and Mae Chan faults constitute the northeast and east boundaries of the eastward extrusion, with their left slip rates being 0.3-14.7, 8.9-17.1, 5.1 ± 2.5, 2.8 ± 2.3, 7.1 ± 2.1, 9.4 ± 1.2, 10.1 ± 2.0, 7.3 ± 2.6, and 4.9 ± 3.0 mm/a respectively. The southwestern boundary consists of a widely distributed dextral transpressional zone other than a single fault. Right slip rates of 4.2 ± 1.3, 4.3 ± 1.1, and 8.5 ± 1.7 mm/a are detected across the Nanhua-Chuxiong-Jianshui, Wuliangshan, and Longling-Lancang faults. Crustal deformation across the Longmenshan fault is weak, with short-ening rates of 1.4 ± 1.0 and 1.6 ± 1.3 mm/a across the Baoxing-Beichuan and Beichuan-Qingchuan segments. Northwest of the Longmenshan fault lies an active deformation zone (the Longriba fault) with 5.1±1.2 mm/a right slip across. Relatively large slip rates are detected across a few faults within the Sichuan-Yunnan block: 4.4±1.3 mm/a left slip and 2.7±1.1 mm/a shortening across the Litang fault, and 2.7±2.3 mm/a right-lateral shearing and 6.7±2.3 mm/a shortening across the Yunongxi fault and its surrounding regions. In conclusion, we find that the Sichuan-Yunnan region is divided into more than a dozen active micro-blocks by a large number of faults with relatively slow slip rates. The eastward extrusion of the Tibetan Plateau is absorbed and adjusted in the region mainly by these faults, other than a small number of large strike-slip faults with fast slip rates.展开更多
Active tectonics, e.g., faulting, folding, and rifting are clearly manifested over the vast territory of China. The in-tensive crustal deformation with long-lived structures has given rise to numerous highly-elevated ...Active tectonics, e.g., faulting, folding, and rifting are clearly manifested over the vast territory of China. The in-tensive crustal deformation with long-lived structures has given rise to numerous highly-elevated mountains in the western China with the Yangtze and Yellow rivers downstreaming to the east,as well as resulting in catastrophicearthquakes with huge fatalities in the historical times. Quantifying crustal deformation into its amount, distribu- tion, and timing is prerequisite for an understanding of the nature of geological evolution, climate-tectonics interaction, and ultimately the geodynamic aspects that control these processes. Moreover, monitoring active deformation with great precision is of fundamental importance in trying to forecast earthquake or assess seismic hazard for an earth- quake-prone country like China.展开更多
Based on the multiple-epoch Global Positioning System observations during a period from 1992 to 1999, we document directly a rapid crustal shortening of -20 mm/a across the western Tianshan Mts. (76°E), in contra...Based on the multiple-epoch Global Positioning System observations during a period from 1992 to 1999, we document directly a rapid crustal shortening of -20 mm/a across the western Tianshan Mts. (76°E), in contrast to a 4 mm/a convergent rate across the eastern Tianshan Mts. (87°E) and the north-south convergence across the mountain belt descends laterally from west to east. The direction of current crustal movement inferred by GPS sites along the southern flank of the Tianshan Mts. is approximately perpendicular to the easterly-trending mountain belt, indicating that the Tarim Basin thrust almost rightly into the Tianshan Mts. The Tarim Basin accommodates nearly no or a minor, if any, crustal deformation and rotates clockwise, as a rigid body in a whole, at a rate of 0.64°/Ma around a Euler pole at 95.7° E, 40.3°N (Anxi, Gansu) with respect to the stable Siberia. The relative motion between the Kazakh platform and the Dzungarian Basin is quite apparent. The Dzungar should be regarded as an展开更多
基金The study is funded by the National Natural Science Foundation of China(41274027,41274037,41374030 and 41474097)
文摘The 2008 Nura Mw6.7 earthquake occurred in front of the Trans-Alai Range, central Asia. We present Interferometric Synthetic Aperture Radar （InSAR） measurements of its coseismic ground deformation that are available for a major earthquake in the region. Analysis of the InSAR data shows that the earthquake ruptured a secondary fault of the Main Pamir Thrust for about 20 kin. The fault plane striking N46~E and dipping 48~SE is dominated by thrust slip up to 3 m, most of which is confined to the uppermost 2-5 km of the crust, similar to the nearby 1974 MwT.0 Markansu earthquake. The elastic model of interseismic deformation constrained by GPS measurements suggests that the two earthquakes may have resulted from the failures of two high-angle reverse faults that are about 10 km apart and rooted in a locked dScollement at depths of 5-6 kin. The elastic strain is built up by a freely creeping decollement at about 16 mm/a.
基金supported by the National Natural Science Foundation of China(41274027)the Director Foundation of Institute of Seismology, China Earthquake Administration(IS201156063)
文摘The April 20, 2013, Ms7.0 Lushan earthquake was successfully recorded by closely spaced Continuous Global Positioning System （CGPS） stations owned by the Crustal Movement Observation Network of Chi- na （CMONC）. The 1-Hz GNSS data from eight CGPS stations, which are located between 30 km and 200 km from the hypocenter, were processed within quasi-real-time. The near-field surface deformation indicated the following characteristics ： the near-field movements were limited to several centimeters ; the peak of the deformation wave was significantly larger than the static permanent offset; at the beginning of the event, the north wall of the fault moved to the southeast as the south wall moved to the southwest ; station SCTQ, which was the closest station to the hypocenter at 30 km, had the largest static permanent displacement of 2 cm; the peaks of the deformation waves were 1.5 cm, 5 cm and 3 cm, to the east, the south and vertically upward, respectively ; and the peaks of velocity and acceleration, derived from the deformation, were 3.4 cm/s and 5.3 cm/s^2,respectively.
基金supported by National Natural Science Foundation of China( 41004008) Key Foundation of Institute of Seismology China Earthquake Administration ( IS201026019) +3 种基金State Key Laboratory of Cryo-spheric Sciences,Cold and Arid Regions Environment and Engineering Research Institute,Chinese Academy of Sciences ( SKL CS09 - 03) the Foundation of State Key Laboratory of Water Resources and Hydropower Engineering Science,Wuhan University( 2009B54) the Foundation of Institute of Seismology China Earthquake Administration( IS200826057 ) National Key Technology R&D Program of China( 2008BAC35B04 -5)
文摘Co-seismic ground-surface deformation of the Yushu earthquake on April 14, 2010 is studied on the basis of interferometry principle by using InSAR images from ALOS PALSAR and ENVISAT ASAR pairs. The observed maximum line-of-sight displacement is 54 cm, which is equivalent to a sinistral strike slip of 180 cm on the surface. The location of macro-epicenter is very close to the epicenter determined by in situ investigation, suggesting that InSAR is an ideal tool for quick identification of the macro-epicenter, and thus for timely disaster assessment after a destructive earthquake.
基金sponsored by the National Natural Science Foundation of China(41474016,41474051,41474097)
文摘The Underground Gas Storage( UGS) in Hutubi( HTB),Xinjiang is the largest gas storage reservoir in China and it has significance for coordinating the gas supply and demand relationship,peak-load regulation,implementation of strategic reserves,national security, and social economic sustainable development. Therefore, the deformation monitoring and simulation analysis of UGS operation has important technical support and reference value for the stability and safe operation of the underground gas storage. In this paper,we use the elevation data obtained from 7 periods of second-order leveling surveys in the Hutubi underground gas storage area in 2013- 2015 to analyze the influence of gas well pressure on the vertical deformation of the underground gas storage reservoir.Research has shown that the absolute vertical subsidence rate is approximately in the range from 11. 8mm to 16. 1mm and the relative subsidence change is about 4. 3mm,near the surface deformation of Hutubi underground gas storage area except for the annual subsidence rate of- 2. 86 mm by the basic influence of uplift of the Tianshan Mountains.Groundwater over-extraction in the Hutubi area also has an impact on the vertical variation of the surface in this region. The land surface change per unit pressure of gas storage has an impact of about 0. 625mm- 1. 125 mm. 17 scenes Terra SAR-X radar images acquired from August,2013 to August,2014 are exploited by Small Baseline Subset( SBAS) In SAR method to obtain the surface deformation time series during the operation of UGS in Hutubi,meanwhile combined with the pressure data of injection / productionwells,the multi-point source Mogi model is used to simulate the UGS deformation field in Hutubi. The results show that the deformation characteristics of the whole UGS area is a discontinuous distribution with the peak deformation value of 10 mm and- 8mm in the satellite line of sight( LOS) during gas injection and production,respectively and the retrieved deformation sequences correspond very well to the gas injection / production pressure changes. Based on the multi- point source Mogi model, we simulate the deformation process of UGS,HTB,and with the adaptive forward search method,the radius and depth of point source are obtained. The simulated results indicate that when the average injection / production pressure of UGS,HTB is 18 MPa and 15 MPa, LOS deformation is up to 7mm and- 4mm,respectively,and surface deformation is related to the density of gas injection( production) wells. The UGS gas distribution is not uniform,indicating that the structure of underground gas storage is complex. Thus using a more elaborate geomechanical model and other deformation observation data will be helpful for better simulating the UGS internal structure and explaining the mechanism of deformation.
基金sponsored by the National Natural Science Foundation of China(41474097,41304067,47474016,41474051,41404015)
文摘The deformation responses of surface cap rocks of Underground Gas Storage( UGS) in Hutubi,Xinjiang during gas injection and production were investigated with the GPS data recorded by the deformation monitoring network,which includes 13 observation sites. The time series of three-dimensional deformation of the surface cap rocks was obtained in the UGS operation process,and the deformation signals in different phases were identified by combining the GPS data with wellhead pressure data. The results show that the respiration response of surface cap rock deformation is obvious during gas injection and production of UGS,and the surface deformation due to a 1MPa change of wellhead pressure is 1. 02 mm in gas injection and 1. 24 mm in gas production horizontally, and- 1. 11 mm in gas injection and 0. 86 mm in gas production vertically.
基金the National Basic Research Program of China (Grant No. 2004CB418403)the Key Program of the National Natural Science Foundation of China (Grant No. 40334042)the China Earthquake Administration Research Fund (Grant No. 200708002)
文摘A linked-fault-element model is employed to invert for contemporary slip rates along major active faults in the Sichuan-Yunnan region (96°-108°E, 21°-35°N) using the least squares method. The model is based on known fault geometry, and constrained by a GPS-derived horizontal velocity field. Our results support a model attributing the eastward extrusion of the Tibetan Plateau driven mainly by the north-northeastward indentation of the Indian plate into Tibet and the gravitational collapse of the plateau. Resisted by a relatively stable south China block, materials of the Sichuan-Yunnan region rotate clockwise around the eastern Himalayan tectonic syntaxis. During the process the Garzê-Yushu, Xianshuihe, Anninghe, Zemuhe, Daliangshan, and Xiaojiang faults, the southwest extension of the Xiaojiang fault, and the Daluo-Jinghong and Mae Chan faults constitute the northeast and east boundaries of the eastward extrusion, with their left slip rates being 0.3-14.7, 8.9-17.1, 5.1 ± 2.5, 2.8 ± 2.3, 7.1 ± 2.1, 9.4 ± 1.2, 10.1 ± 2.0, 7.3 ± 2.6, and 4.9 ± 3.0 mm/a respectively. The southwestern boundary consists of a widely distributed dextral transpressional zone other than a single fault. Right slip rates of 4.2 ± 1.3, 4.3 ± 1.1, and 8.5 ± 1.7 mm/a are detected across the Nanhua-Chuxiong-Jianshui, Wuliangshan, and Longling-Lancang faults. Crustal deformation across the Longmenshan fault is weak, with short-ening rates of 1.4 ± 1.0 and 1.6 ± 1.3 mm/a across the Baoxing-Beichuan and Beichuan-Qingchuan segments. Northwest of the Longmenshan fault lies an active deformation zone (the Longriba fault) with 5.1±1.2 mm/a right slip across. Relatively large slip rates are detected across a few faults within the Sichuan-Yunnan block: 4.4±1.3 mm/a left slip and 2.7±1.1 mm/a shortening across the Litang fault, and 2.7±2.3 mm/a right-lateral shearing and 6.7±2.3 mm/a shortening across the Yunongxi fault and its surrounding regions. In conclusion, we find that the Sichuan-Yunnan region is divided into more than a dozen active micro-blocks by a large number of faults with relatively slow slip rates. The eastward extrusion of the Tibetan Plateau is absorbed and adjusted in the region mainly by these faults, other than a small number of large strike-slip faults with fast slip rates.
基金supported by the National Natural Science Foundation of China (Grant Nos. 40674054,41074016)the CMONOC Project
文摘Active tectonics, e.g., faulting, folding, and rifting are clearly manifested over the vast territory of China. The in-tensive crustal deformation with long-lived structures has given rise to numerous highly-elevated mountains in the western China with the Yangtze and Yellow rivers downstreaming to the east,as well as resulting in catastrophicearthquakes with huge fatalities in the historical times. Quantifying crustal deformation into its amount, distribu- tion, and timing is prerequisite for an understanding of the nature of geological evolution, climate-tectonics interaction, and ultimately the geodynamic aspects that control these processes. Moreover, monitoring active deformation with great precision is of fundamental importance in trying to forecast earthquake or assess seismic hazard for an earth- quake-prone country like China.
文摘Based on the multiple-epoch Global Positioning System observations during a period from 1992 to 1999, we document directly a rapid crustal shortening of -20 mm/a across the western Tianshan Mts. (76°E), in contrast to a 4 mm/a convergent rate across the eastern Tianshan Mts. (87°E) and the north-south convergence across the mountain belt descends laterally from west to east. The direction of current crustal movement inferred by GPS sites along the southern flank of the Tianshan Mts. is approximately perpendicular to the easterly-trending mountain belt, indicating that the Tarim Basin thrust almost rightly into the Tianshan Mts. The Tarim Basin accommodates nearly no or a minor, if any, crustal deformation and rotates clockwise, as a rigid body in a whole, at a rate of 0.64°/Ma around a Euler pole at 95.7° E, 40.3°N (Anxi, Gansu) with respect to the stable Siberia. The relative motion between the Kazakh platform and the Dzungarian Basin is quite apparent. The Dzungar should be regarded as an
