The Yinwashan and Xinminpu faults are located in the Jiuxi Basin in the western end of the Hexi Corridor. The determination of their activity and slip rates is of great significance for understanding the eastward exte...The Yinwashan and Xinminpu faults are located in the Jiuxi Basin in the western end of the Hexi Corridor. The determination of their activity and slip rates is of great significance for understanding the eastward extension of the Altyn Tagh fault. Based on geological and geomorphologic field survey, trench excavation, optically stimulated luminescence dating, we define the fault geometry and kinematic properties of the two faults. Based on fault scarps measurement using differential GPS and 10 Be surface exposure dating, we determined vertical slip rate of 0.09±0.01 mm/yr for the Yinwashan fault and 0.1±0.02 mm/yr for the Xinminpu fault. Using the dips observed in trenches and natural sections, we estimated horizontal shortening rates of 0.05±0.03 and 0.23±0.06 mm/yr, respectively. No significant strike slip motion is observed on these two faults, and we infer that this region was dominated by horizontal shortening in the Late Quaternary. Although the shortening rate is quite low on each individual fault, together with other faults in this area, these two faults have an essential role in transferring slip from the eastern end of the Altyn Tagh fault and in accommodating the northeastward growth of Tibetan Plateau.展开更多
The Yangtze River Economic Belt(YREB)spans three terrain steps in China and features diverse topography that is characterized by significant differences in geological structure and presentday crustal deformation.Activ...The Yangtze River Economic Belt(YREB)spans three terrain steps in China and features diverse topography that is characterized by significant differences in geological structure and presentday crustal deformation.Active faults and seismic activity are important geological factors for the planning and development of the YREB.In this paper,the spatial distribution and activity of 165 active faults that exist along the YREB have been compiled from previous findings,using both remote-sensing data and geological survey results.The crustal stability of seven particularly noteworthy typical active fault zones and their potential effects on the crustal stability of the urban agglomerations are analyzed.The main active fault zones in the western YREB,together with the neighboring regional active faults,make up an arc fault block region comprising primarily of Sichuan-Yunnan and a“Sichuan-Yunnan arc rotational-shear active tectonic system”strong deformation region that features rotation,shear and extensional deformation.The active faults in the central-eastern YREB,with seven NE-NNE and seven NW-NWW active faults(the“7-longitudinal,7-horizontal”pattern),macroscopically make up a“chessboard tectonic system”medium-weak deformation region in the geomechanical tectonic system.They are also the main geological constraints for the crustal stability of the YREB.展开更多
The Uludağ Range of northwest Türkiye forms a key tectonic boundary between the North Anatolian Fault Zone and the Western Anatolia Extensional Region, where active deformation is expressed across a network of st...The Uludağ Range of northwest Türkiye forms a key tectonic boundary between the North Anatolian Fault Zone and the Western Anatolia Extensional Region, where active deformation is expressed across a network of strike-slip and normal faults. To investigate how fault segmentation and kinematics control landscape evolution in this complex orogen, we integrate high-resolution morphometric analysis with paleoseismological data. We extracted key morphometric indices-including Δ-relief, Δ-elevation, Δ-gradient, Δχ, hypsometric integral, channel concavity(m/n), normalized channel steepness(ksn), and knickpoint distribution-from 10-meter DEMs using open-source geomorphic toolkits. Our results demonstrate pronounced spatial variability in geomorphic signatures and tectonic activity across four divide segments(DS). DS01, associated with the right-lateral Ulubat Fault, exhibits exceptional morphometric stability and minimal disequilibrium, in line with long earthquake recurrence intervals and low Holocene slip rates. In contrast, DS02 and DS03-bounded by the Bursa and Soğukpınar faults-display χ-based divide migration and subtle landscape adjustment. DS04, influenced by the İnegöl and Oylat faults, is characterized by elevated channel steepness, dense knickpoint clustering, and southward divide migration, collectively indicating ongoing uplift and transient drainage adjustment. The strong correspondence between morphometric disequilibrium and documented earthquake recurrence patterns highlights the critical value of integrating geomorphic and paleoseismological datasets. Our findings demonstrate that only through the convergence and cross-validation of multiple independent metrics can the segmented imprint of active deformation be reliably detected-particularly where landscape response is temporally offset from fault activity. The methodological framework developed here provides a robust template for quantifying active structures and their geomorphic consequences and can be widely applied to other tectonically complex mountain belts for seismic hazard assessment and landscape evolution studies.展开更多
As shallow salt lake resources are increasingly exploited,deep confined brine has become a strategic alternative due to its widespread distribution and significant reserve potential.However,unfavorable reservoir chara...As shallow salt lake resources are increasingly exploited,deep confined brine has become a strategic alternative due to its widespread distribution and significant reserve potential.However,unfavorable reservoir characteristics,particularly low permeability and poor recovery efficiency,have historically rendered these deposits uneconomic,restricting their utilization.Taking the Mahai Salt Lake in the Qaidam Basin as a representative case,this study investigates the structural controls on brine enrichment through an integrated approach.Previous long-term metallogenic studies and exploration data indicate occurrences of an extensional fault zone favorable for brine accumulation.Therefore,we applied InSAR deformation analysis to assess coseismic and postseismic surface responses.Combined with radon-222 emanation mapping,our findings reveal a strong spatial correlation between high-productivity brine boreholes and active fault systems.The existence of active faults enhance brine migration and storage,provided that the target reservoirs have substantial halite thickness and maintain relatively low clay-silt content.展开更多
Riedel shear system,which consists of some different oriented faults and derivative structures,is an important pattern of tectonic activity and stress regulation,which has been widely applied to the interpretation of ...Riedel shear system,which consists of some different oriented faults and derivative structures,is an important pattern of tectonic activity and stress regulation,which has been widely applied to the interpretation of intracontinental deformation.The Laolongwan Basin,located in the western Haiyuan fault zone at the northeastern Tibetan Plateau,is a key area to study the Cenozoic intracontinental deformation in the northeastern plateau,which formed a complex active fault system during the Cenozoic.However,the activity of these faults and their kinematic mechanism remain unclear.In this contribution,based on detailed structural interpretation of remote sensing image,field observations and OSL dating analysis,we propose a Riedel Shear model of active fault system in the Laolongwan Basin.Our observations show that this active fault system consist of four major faults,including the left strike-slip Hasi Shan fault and Zihong Shan fault with thrusting characteristics,the Southern Zihong Shan thrust fault and the Mijia Shan normal fault.The fault offset and OSL dating analyses suggest that the left-lateral slip rate of the Hasi Shan fault is~2.60-3.01 mm/a since ca.15 ka,whereas the Zihong Shan fault is~1.10-1.13 mm/a since ca.14 ka.Faultslip vectors analyses indicate that the active fault system related to the Riedel Shear in the Laolongwan Basin was controlled by the regional ENE-WSW compressive stress.This compression also caused the significant left-lateral strike-slip movement along the Haiyuan fault zone at the same time,which might result from the northeastward continuous expanding of the Tibetan Plateau during the Late Cenozoic.展开更多
This study used 2D seismic profiles to investigate the Cenozoic evolution of faults in the Huizhou Sub-basin. It aims to define the basin structure style through describing the geometric fea- tures of the faults and q...This study used 2D seismic profiles to investigate the Cenozoic evolution of faults in the Huizhou Sub-basin. It aims to define the basin structure style through describing the geometric fea- tures of the faults and quantitatively analyzing their activities. The results indicate that the boundary faults in the Huizhou Sub-basin display en echelon arrangement in plan view, which indicates that, it was caused by a kind of oblique extension. Calculating the fault slips shows long-term activities of faults occurred in the basin, and some boundary faults kept active after 5.5 Ma. The evolution history of the fault system is reconstructed. Initially, during the Eocene-Early Oligocene, mainly NNE-NE and NW trending faults and NE striking grabens and half-grabens formed in the basin and a series of faults system controlled the deposition. During the Late Oligocene--Early Miocene, the structural ac- tivities were relatively weak, the fault activity and the fault growth rate decreased sharply. Finally, in the late stage from Late Miocene to the present, the structure movement was re-activated, and some faults were also reactivated. Our study will help better understand the structural features and evolu- tion of the petroleum-bearing basins in the northern margin of the South China Sea.展开更多
A recent correlation of stream geomorphic indices to fault activity has revealed that stream geomorphologies in bedrock mountain areas are good records of local fault movements. The Daqingshan piedmont fault is one of...A recent correlation of stream geomorphic indices to fault activity has revealed that stream geomorphologies in bedrock mountain areas are good records of local fault movements. The Daqingshan piedmont fault is one of the main active faults in the fault system on the northern margin of the Hetao Basin and has produced frequent large-scale earthquakes since the Late Pleistocene. In the present study, following the segmentation regime of previous studies, we divide the fault zone into five segments, namely, the Baotou, Tuyouqi West, Tuzuoqi West, Bikeqi, and Hohhot segments, and we discuss the relationship between the drainage basin geomorphology and the piedmont fault activity in the Daqingshan area using 30 m spatial resolution Shuttle Radar Topography Mission(SRTM) digital elevation model(DEM) data. We use a range of geomorphic indices to examine the drainage basins in the Daqingshan area, including the channel steepness index(ksn), slope, hypsometric integral(HI), relief degree of land surface(RDLS), and stream lengthgradient index(SL), extracted with ArcGIS and MATLAB, and we also consider local lithologic and climate aspects. Furthermore, we compare the geomorphic indices with the slip rates of individual segments of the Daqingshan piedmont fault and paleoseismic data. The results show that the geomorphic indices of drainage basins in the Daqingshan area are primarily affected by the piedmont fault activity in the Daqingshan area. The geomorphic indices also demonstrate that piedmont fault activity has been the most intense in the middle segment of this fault system since the Late Quaternary and decreases towards the two sides.展开更多
It is important to explore active faults in urban areas and their surroundings for earth- quake disaster mitigation. Satellite remote sensing techniques can play an important role in such active fault exploration. It ...It is important to explore active faults in urban areas and their surroundings for earth- quake disaster mitigation. Satellite remote sensing techniques can play an important role in such active fault exploration. It can not only reveal the pattern of active faults and active tectonics on a macroscop- ic scale, but also monitor the occurrence, development and rules of temporal-spatial evolution of active faults. In this paper, we use the Hangzhou area as an example to introduce methods of extracting de- tailed active fault information when covered by thick unconsolidated Quaternary sediment, using im- age enhancement and image fusion etc. to improve the definition and precision of satellite images and presenting a three-dimensional （3D） image to illustrate tectono-geomorphic features along the relevant faults. We have also collected aeromagnetic anomaly data, shallow seismic exploration data and dating data, and carried out field surveys to validate the characteristics of active faults based on remote sens- ing images. The results revealed about the faults showed a high consistency with traditional geological knowledge, and demonstrate that it is feasible to explore active faults in a weakly active tectonic area by using satellite remote sensing techniques and contribute to large engineering projects and research on neotectonics.展开更多
The geology and tectonics in the eastern margin of Tibetan Plateau are complex. The main tectonic framework is composed of blocks and faults. Using discontinuous global positioning system survey data for 2008–2014, t...The geology and tectonics in the eastern margin of Tibetan Plateau are complex. The main tectonic framework is composed of blocks and faults. Using discontinuous global positioning system survey data for 2008–2014, the velocity field for the Eurasia reference framework was obtained. Based on the velocity field, the present-day velocities of the blocks and boundary faults were estimated. The results reveal that the movement rates of the Chuan-Qing, South China, Chuan-Dian and Indo-China blocks are（17.02±0.60） mm/a,（8.77±1.51） mm/a,（13.85±1.31） mm/a and（6.84 ± 0.74） mm/a, respectively, and their movement directions are 99.5°, 120.3°, 142.9° and 153.3°, respectively. All blocks exhibit clockwise rotation. The displacement rates of the Xianshuihe, Longmenshan, Anninghe, Zemuhe, Xiaojiang and Red River faults are（7.30±1.25–8.30±1.26） mm/a,（10.07±0.97–11.79±0.89） mm/a,（0.96±0.74–2.98±1.73） mm/a,（2.03±0.49–3.20±0.73） mm/a,（3.45±0.40–6.02±0.50） mm/a and（6.23±0.56） mm/a, respectively. The Xianshuihe, Anninghe, Zemuhe and Xiaojiang faults show leftlateral strike-slip movement, while the Longmenshan and Red River faults show right-lateral strikeslip. These characteristics of the blocks and faults are related to the particular tectonic location and dynamic mechanism.展开更多
Lateral migration of fault activity in Weihe basin is a popular phenomenon and its characteristics are also typical. Taking the activity migrations of Wangshun Mountain piedmont fault toward Lishan piedmont fault and ...Lateral migration of fault activity in Weihe basin is a popular phenomenon and its characteristics are also typical. Taking the activity migrations of Wangshun Mountain piedmont fault toward Lishan piedmont fault and Weinan platform front fault, Dabaopi-Niujiaojian fault toward Shenyusi-Xiaojiazhai fault, among a serial of NE-trending faults from Baoji city to Jingyang County as examples, their migration time and process are analyzed and discussed in the present paper. It is useful for further understanding the structure development and physiognomy evolution history of Weihe basin.展开更多
-On the basis of the data of geophysics and seismic activities, the analyses of the active faults, seismic activities and the sea floor unstable factors of the Zhujiang River Mouth Basin have been made so as to study ...-On the basis of the data of geophysics and seismic activities, the analyses of the active faults, seismic activities and the sea floor unstable factors of the Zhujiang River Mouth Basin have been made so as to study the characteristics of the compressional subactive continental margin of Cathaysian system, arc littoral strongly active fracture zone, the division of seismic subzone and seismic zone of the continental margin of northern South China Sea, the potential focal area, and to analyze the regional stability. We consider that the Zhujiang River Mouth Basin belongs to a stable or a moderately stable region.展开更多
The 1605 M7½ Earthquake is the only earthquake in the history of China that has caused large-scale land subsidence into the sea,with the total area of land subsidence exceeding 100 km2.The disaster has led to the...The 1605 M7½ Earthquake is the only earthquake in the history of China that has caused large-scale land subsidence into the sea,with the total area of land subsidence exceeding 100 km2.The disaster has led to the sinking of 72 villages.There is still no clear understanding of the source seismogenic fault of this earthquake.In this work,we conducted a detailed study of the middle segment of the Maniao-Puqian fault(MPF),which is the epicenter area,through geomorphological survey,data collection,shallow seismic exploration,cross-section drilling,and chronological dating.The results showed that the middle segment of the MPF zone is composed of three nearly parallel normal faults with a dextral strike-slip:“Macun-Luodou fault(F2-1),Haixiu-Dongyuan fault(F2-2),and ChangliuZhuxihe fault(F2-3)”.And F2-2 is composed of two secondary faults,namely F2-2′and F2-2″,with a flower-shaped structure buried under the ground.It is distributed nearly east-west,dipping to the north and has experienced at least five stages of activities since the Miocene.The vertical activity rates of F2-2′and F2-2″are~2.32 and~2.5 mm/a,since the Holocene,respectively.There were eight cycles of transgression and regression since the Miocene.The fault activity resulted in the thickening of the Holocene strata with a slight dip to the south,on the hanging wall,showing V-shaped characteristics.The MPF is likely the source seismogenic fault of the M7½ earthquake that hit Qiongshan in 1605.展开更多
On the basis of a 3-dimension visco-elastic finite element model of lithosphere in North China, we numerically simulate the recent mutative figures of tectonic stress field. Annual change characteristics of stress fie...On the basis of a 3-dimension visco-elastic finite element model of lithosphere in North China, we numerically simulate the recent mutative figures of tectonic stress field. Annual change characteristics of stress field are： 1 ） Maximum principal tensile stress is about 3 -9 kPaa-1 and its azimuth lie in NNW-SSE. 2） Maximum principal compressive stress is about 1 - 6 kPaa-1 and its azimuth lie in NEE-SWW. 3 ） Maximum principal tensile stress is higher both in the west region and Liaoning Province. 4） Variation of tectonic stress field benefits fault movement in the west part and northeast part of North China. 5 ）Annual accumulative rates of Coulomb fracture stress in Tanlu fault belt have segmentation patterns： Jiashan-Guangji segment is the high- est （6 kPaa - 1 ） , Anshan-Liaodongwan segment is the second （5 kPaa - l ） , and others are relatively lower （ 3 - 4 kPaa-1 ）.展开更多
The Ying-Qiong Basin is located on the northwestern margin of the South China Sea and at the junction of the South China Block and the Indochina Block.It is characterized by complex geological structures.The existing ...The Ying-Qiong Basin is located on the northwestern margin of the South China Sea and at the junction of the South China Block and the Indochina Block.It is characterized by complex geological structures.The existing seismic data in the study area is sparse due to the lack of earthquake activities.Because of the limited source energy and poor coverage of seismic data,the knowledge of deep structures in the area,including the spatial distribution of deep faults,is incomplete.Contrarily,satellite gravity data cover the entire study area and can reveal the spatial distribution of faults.Based on the wavelet multi-scale decomposition method,the Bouguer gravity field in the Ying-Qiong Basin was decomposed and reconstructed to obtain the detailed images of the first-to sixth-order gravitational fields.By incorporating the known geological features,the gravitational field responses of the main faults in the Ying-Qiong Basin were identified in the detailed fields,and the power spectrum analysis yielded the depths of 1.4,8,15,26.5,and 39 km for the average burial depths of the bottom surfaces from the first-to fifth-order detailed fields,respectively.The four main faults in the Yinggehai Basin all have a large active depth range:fault A(No.1)is between 5 and 39 km,fault B is between 26.5 and 39 km,and faults C and D are between 15 and 39 km.However,the depth of active faults in the Qiongdongnan Basin is relatively shallow,mainly between 8 and 26.5 km.展开更多
The Wenchuan earthquake coseismic deformation field is inferred from the coseismic dislocation data based on a 3-D geometric model of the active faults in Sichuan-Yunnan region. Then the potential dislocation displace...The Wenchuan earthquake coseismic deformation field is inferred from the coseismic dislocation data based on a 3-D geometric model of the active faults in Sichuan-Yunnan region. Then the potential dislocation displacement is inverted from the deformation field in the 3-D geometric model. While the faults＇ slip velocities are inverted from GPS and leveling data, which can be used as the long-term slip vector. After the potential dislocation displacements are projected to long-term slip direction, we have got the influence of Wenchuan earthquake on active faults in Sichuan-Yunnan region. The results show that the northwestern segment of Longmenshan fault, the southern segments of Xianshuihe fault, Anninghe fault, Zemuhe fault, northern and southern segments of Daliangshan fault, Mabian fault got earthquake risks advanced of 305, 19, 12, 9.1 and 18, 51 years respectively in the eastern part of Sichuan and Yunnan. The Lijiang-Xiaojinhe fault, Nujiang fault, Longling-Lancang fault, Nantinghe fault and Zhongdian fault also got earthquake risks advanced in the western part of Sichuan-Yunnan region. Whereas the northwestern segment of Xianshuihe fault and Xiaojiang fault got earthquake risks reduced after the Wenchuan earthquake.展开更多
Lanzhou Institute of Seismology, China Seismological Bureau, Lanzhou 730000, China 2) Institute of Geology, China Seismological Bureau, Beijing 100029, China
The Lajishan Mountain fault zone consists of two NE_protruding arcuate faults, i.e. the northern and southern margin fault of Lajishan Mountain with the fault length of 230km and 220km respectively. The fault zone is ...The Lajishan Mountain fault zone consists of two NE_protruding arcuate faults, i.e. the northern and southern margin fault of Lajishan Mountain with the fault length of 230km and 220km respectively. The fault zone is located in the large_scale compressional structure zone and tectonic gradient zone in_between the NNW_trending right_lateral strike_slip Reshui_Riyueshan fault zone and the NWW_trending left_lateral strike_slip northern margin of west Qinling Ranges fault zone is also an important boundary fault zone, separating the Xining_Minhe basin and the Xunhua_Hualong basin at the southern and northern sides of the Lajishan Mountain respectively. Geologic geomorphic evidences of new activity revealed by field investigations indicate that the latest movement of the Lajishan fault zone was in late Epipleistocene (only a few segments were active in early Holocene) and is mainly of compressive thrusting with slightly left_lateral strike_slip component. The above movement has possibly resulted in the occurrence of about 20 moderate earthquakes of magnitude around 5.0. The Lajishan region can therefore be regarded as a seismotectonic window to reflect tectonic movement and earthquake activity.展开更多
On the basis of the Xining active urban fault survey, we studied the relationship between the active urban fault and fold deformation. The result of this research shows that the Huangshuihe fault and the NW-striking f...On the basis of the Xining active urban fault survey, we studied the relationship between the active urban fault and fold deformation. The result of this research shows that the Huangshuihe fault and the NW-striking fault on the northern bank of the Huangshulbe River are tensional faults on top of an anticline, the Nanchuanhe fault is a transverse tear fault resulting from differential folding on two sides of the fault, the east bank of the Beichuanhe River fault is a compressional fault developed on the core or climb of a syncline. By balance profile analysis of fold deformation and inversion of gravity anomaly data, we obtained the depth of the detachment plane and established the seismotectonic model of the ）fining urban area. Based on the seismotectonic model, we analyzed the earthquake potential of the active urban fault.展开更多
Objective The lateral extrusion eastward of the Tibetan Plateau leads to the formation of the Sichuan–Yunnan block, which is the most representative active block in the southeastern margin of the Tibetan Plateau, cha...Objective The lateral extrusion eastward of the Tibetan Plateau leads to the formation of the Sichuan–Yunnan block, which is the most representative active block in the southeastern margin of the Tibetan Plateau, characterized by strong and frequent seismicity(Li Ping et al., 1975; Zhang Peizhen et al., 2003; Li Yong et al., 2017). Its eastern boundary is composed of sinistral faults including the Xianshuihe, Xiaojiang faults, etc., and the western展开更多
基金the Basic Research Project of Institute of Earthquake Science,CEA(No.2019IESLZ01)the National Science Foundation of China(No.41402186)。
文摘The Yinwashan and Xinminpu faults are located in the Jiuxi Basin in the western end of the Hexi Corridor. The determination of their activity and slip rates is of great significance for understanding the eastward extension of the Altyn Tagh fault. Based on geological and geomorphologic field survey, trench excavation, optically stimulated luminescence dating, we define the fault geometry and kinematic properties of the two faults. Based on fault scarps measurement using differential GPS and 10 Be surface exposure dating, we determined vertical slip rate of 0.09±0.01 mm/yr for the Yinwashan fault and 0.1±0.02 mm/yr for the Xinminpu fault. Using the dips observed in trenches and natural sections, we estimated horizontal shortening rates of 0.05±0.03 and 0.23±0.06 mm/yr, respectively. No significant strike slip motion is observed on these two faults, and we infer that this region was dominated by horizontal shortening in the Late Quaternary. Although the shortening rate is quite low on each individual fault, together with other faults in this area, these two faults have an essential role in transferring slip from the eastern end of the Altyn Tagh fault and in accommodating the northeastward growth of Tibetan Plateau.
基金This research is funded by the China Geological Survey project(DD20160268).
文摘The Yangtze River Economic Belt(YREB)spans three terrain steps in China and features diverse topography that is characterized by significant differences in geological structure and presentday crustal deformation.Active faults and seismic activity are important geological factors for the planning and development of the YREB.In this paper,the spatial distribution and activity of 165 active faults that exist along the YREB have been compiled from previous findings,using both remote-sensing data and geological survey results.The crustal stability of seven particularly noteworthy typical active fault zones and their potential effects on the crustal stability of the urban agglomerations are analyzed.The main active fault zones in the western YREB,together with the neighboring regional active faults,make up an arc fault block region comprising primarily of Sichuan-Yunnan and a“Sichuan-Yunnan arc rotational-shear active tectonic system”strong deformation region that features rotation,shear and extensional deformation.The active faults in the central-eastern YREB,with seven NE-NNE and seven NW-NWW active faults(the“7-longitudinal,7-horizontal”pattern),macroscopically make up a“chessboard tectonic system”medium-weak deformation region in the geomechanical tectonic system.They are also the main geological constraints for the crustal stability of the YREB.
基金supported by the Disaster and Emergency Management Authority of Türkiye(AFAD)under the project code UDAP-G-18-01。
文摘The Uludağ Range of northwest Türkiye forms a key tectonic boundary between the North Anatolian Fault Zone and the Western Anatolia Extensional Region, where active deformation is expressed across a network of strike-slip and normal faults. To investigate how fault segmentation and kinematics control landscape evolution in this complex orogen, we integrate high-resolution morphometric analysis with paleoseismological data. We extracted key morphometric indices-including Δ-relief, Δ-elevation, Δ-gradient, Δχ, hypsometric integral, channel concavity(m/n), normalized channel steepness(ksn), and knickpoint distribution-from 10-meter DEMs using open-source geomorphic toolkits. Our results demonstrate pronounced spatial variability in geomorphic signatures and tectonic activity across four divide segments(DS). DS01, associated with the right-lateral Ulubat Fault, exhibits exceptional morphometric stability and minimal disequilibrium, in line with long earthquake recurrence intervals and low Holocene slip rates. In contrast, DS02 and DS03-bounded by the Bursa and Soğukpınar faults-display χ-based divide migration and subtle landscape adjustment. DS04, influenced by the İnegöl and Oylat faults, is characterized by elevated channel steepness, dense knickpoint clustering, and southward divide migration, collectively indicating ongoing uplift and transient drainage adjustment. The strong correspondence between morphometric disequilibrium and documented earthquake recurrence patterns highlights the critical value of integrating geomorphic and paleoseismological datasets. Our findings demonstrate that only through the convergence and cross-validation of multiple independent metrics can the segmented imprint of active deformation be reliably detected-particularly where landscape response is temporally offset from fault activity. The methodological framework developed here provides a robust template for quantifying active structures and their geomorphic consequences and can be widely applied to other tectonically complex mountain belts for seismic hazard assessment and landscape evolution studies.
基金supported by the National Key Research and Development Program Projects(2023YFC2906502 and 2018YFC0604801)。
文摘As shallow salt lake resources are increasingly exploited,deep confined brine has become a strategic alternative due to its widespread distribution and significant reserve potential.However,unfavorable reservoir characteristics,particularly low permeability and poor recovery efficiency,have historically rendered these deposits uneconomic,restricting their utilization.Taking the Mahai Salt Lake in the Qaidam Basin as a representative case,this study investigates the structural controls on brine enrichment through an integrated approach.Previous long-term metallogenic studies and exploration data indicate occurrences of an extensional fault zone favorable for brine accumulation.Therefore,we applied InSAR deformation analysis to assess coseismic and postseismic surface responses.Combined with radon-222 emanation mapping,our findings reveal a strong spatial correlation between high-productivity brine boreholes and active fault systems.The existence of active faults enhance brine migration and storage,provided that the target reservoirs have substantial halite thickness and maintain relatively low clay-silt content.
基金financially supported by the Natural Science Foundation of Chongqing,China(No.cstc2020jcyj-msxm X0487)the Open Fund of Key Laboratory of Sedimentary Basins and Oil and Gas Resources,the Ministry of Natural Resources(No.cdcgs2022006)+2 种基金the National Natural Science Foundation of China(No.42072001)the China Geological Survey(No.DD20190018)the Science and Technology Innovation Fund for Postgraduates of Chongqing University of Science and Technology(No.YKJCX2220101)。
文摘Riedel shear system,which consists of some different oriented faults and derivative structures,is an important pattern of tectonic activity and stress regulation,which has been widely applied to the interpretation of intracontinental deformation.The Laolongwan Basin,located in the western Haiyuan fault zone at the northeastern Tibetan Plateau,is a key area to study the Cenozoic intracontinental deformation in the northeastern plateau,which formed a complex active fault system during the Cenozoic.However,the activity of these faults and their kinematic mechanism remain unclear.In this contribution,based on detailed structural interpretation of remote sensing image,field observations and OSL dating analysis,we propose a Riedel Shear model of active fault system in the Laolongwan Basin.Our observations show that this active fault system consist of four major faults,including the left strike-slip Hasi Shan fault and Zihong Shan fault with thrusting characteristics,the Southern Zihong Shan thrust fault and the Mijia Shan normal fault.The fault offset and OSL dating analyses suggest that the left-lateral slip rate of the Hasi Shan fault is~2.60-3.01 mm/a since ca.15 ka,whereas the Zihong Shan fault is~1.10-1.13 mm/a since ca.14 ka.Faultslip vectors analyses indicate that the active fault system related to the Riedel Shear in the Laolongwan Basin was controlled by the regional ENE-WSW compressive stress.This compression also caused the significant left-lateral strike-slip movement along the Haiyuan fault zone at the same time,which might result from the northeastward continuous expanding of the Tibetan Plateau during the Late Cenozoic.
基金supported by the National Natural Science Foundation of China (Nos. 41272121, 91028009, 41102071)the Program of Introducing Talents of Discipline to Universities (No. B14031)
文摘This study used 2D seismic profiles to investigate the Cenozoic evolution of faults in the Huizhou Sub-basin. It aims to define the basin structure style through describing the geometric fea- tures of the faults and quantitatively analyzing their activities. The results indicate that the boundary faults in the Huizhou Sub-basin display en echelon arrangement in plan view, which indicates that, it was caused by a kind of oblique extension. Calculating the fault slips shows long-term activities of faults occurred in the basin, and some boundary faults kept active after 5.5 Ma. The evolution history of the fault system is reconstructed. Initially, during the Eocene-Early Oligocene, mainly NNE-NE and NW trending faults and NE striking grabens and half-grabens formed in the basin and a series of faults system controlled the deposition. During the Late Oligocene--Early Miocene, the structural ac- tivities were relatively weak, the fault activity and the fault growth rate decreased sharply. Finally, in the late stage from Late Miocene to the present, the structure movement was re-activated, and some faults were also reactivated. Our study will help better understand the structural features and evolu- tion of the petroleum-bearing basins in the northern margin of the South China Sea.
基金supported by a research grant from the Institute of Crustal Dynamics,China Earthquake Administration(No.ZDJ2019-21)the National Natural Science Foundation of China(Nos.41872227,41602221)。
文摘A recent correlation of stream geomorphic indices to fault activity has revealed that stream geomorphologies in bedrock mountain areas are good records of local fault movements. The Daqingshan piedmont fault is one of the main active faults in the fault system on the northern margin of the Hetao Basin and has produced frequent large-scale earthquakes since the Late Pleistocene. In the present study, following the segmentation regime of previous studies, we divide the fault zone into five segments, namely, the Baotou, Tuyouqi West, Tuzuoqi West, Bikeqi, and Hohhot segments, and we discuss the relationship between the drainage basin geomorphology and the piedmont fault activity in the Daqingshan area using 30 m spatial resolution Shuttle Radar Topography Mission(SRTM) digital elevation model(DEM) data. We use a range of geomorphic indices to examine the drainage basins in the Daqingshan area, including the channel steepness index(ksn), slope, hypsometric integral(HI), relief degree of land surface(RDLS), and stream lengthgradient index(SL), extracted with ArcGIS and MATLAB, and we also consider local lithologic and climate aspects. Furthermore, we compare the geomorphic indices with the slip rates of individual segments of the Daqingshan piedmont fault and paleoseismic data. The results show that the geomorphic indices of drainage basins in the Daqingshan area are primarily affected by the piedmont fault activity in the Daqingshan area. The geomorphic indices also demonstrate that piedmont fault activity has been the most intense in the middle segment of this fault system since the Late Quaternary and decreases towards the two sides.
基金supported by the Major Research Project of the Ministry of Land and Resources,China(No.1212011120887)
文摘It is important to explore active faults in urban areas and their surroundings for earth- quake disaster mitigation. Satellite remote sensing techniques can play an important role in such active fault exploration. It can not only reveal the pattern of active faults and active tectonics on a macroscop- ic scale, but also monitor the occurrence, development and rules of temporal-spatial evolution of active faults. In this paper, we use the Hangzhou area as an example to introduce methods of extracting de- tailed active fault information when covered by thick unconsolidated Quaternary sediment, using im- age enhancement and image fusion etc. to improve the definition and precision of satellite images and presenting a three-dimensional （3D） image to illustrate tectono-geomorphic features along the relevant faults. We have also collected aeromagnetic anomaly data, shallow seismic exploration data and dating data, and carried out field surveys to validate the characteristics of active faults based on remote sens- ing images. The results revealed about the faults showed a high consistency with traditional geological knowledge, and demonstrate that it is feasible to explore active faults in a weakly active tectonic area by using satellite remote sensing techniques and contribute to large engineering projects and research on neotectonics.
基金supported by a geological survey project of the China Geological Survey(No.1212011140013,No.12120113009800,No.121201010000150001)
文摘The geology and tectonics in the eastern margin of Tibetan Plateau are complex. The main tectonic framework is composed of blocks and faults. Using discontinuous global positioning system survey data for 2008–2014, the velocity field for the Eurasia reference framework was obtained. Based on the velocity field, the present-day velocities of the blocks and boundary faults were estimated. The results reveal that the movement rates of the Chuan-Qing, South China, Chuan-Dian and Indo-China blocks are（17.02±0.60） mm/a,（8.77±1.51） mm/a,（13.85±1.31） mm/a and（6.84 ± 0.74） mm/a, respectively, and their movement directions are 99.5°, 120.3°, 142.9° and 153.3°, respectively. All blocks exhibit clockwise rotation. The displacement rates of the Xianshuihe, Longmenshan, Anninghe, Zemuhe, Xiaojiang and Red River faults are（7.30±1.25–8.30±1.26） mm/a,（10.07±0.97–11.79±0.89） mm/a,（0.96±0.74–2.98±1.73） mm/a,（2.03±0.49–3.20±0.73） mm/a,（3.45±0.40–6.02±0.50） mm/a and（6.23±0.56） mm/a, respectively. The Xianshuihe, Anninghe, Zemuhe and Xiaojiang faults show leftlateral strike-slip movement, while the Longmenshan and Red River faults show right-lateral strikeslip. These characteristics of the blocks and faults are related to the particular tectonic location and dynamic mechanism.
基金Chinese Joint Seismological Science Foundation (100120) and State Key Basic Research Development and Programming Project of China (G199804070102).
文摘Lateral migration of fault activity in Weihe basin is a popular phenomenon and its characteristics are also typical. Taking the activity migrations of Wangshun Mountain piedmont fault toward Lishan piedmont fault and Weinan platform front fault, Dabaopi-Niujiaojian fault toward Shenyusi-Xiaojiazhai fault, among a serial of NE-trending faults from Baoji city to Jingyang County as examples, their migration time and process are analyzed and discussed in the present paper. It is useful for further understanding the structure development and physiognomy evolution history of Weihe basin.
基金This study granted by the Scientific Foundation of the China Academy of Science, is one of the stage results of the subject (R850835). A symposium of the International Petroleum Geological Conference of Northern South China Sea Continental Shelf, 1987
文摘-On the basis of the data of geophysics and seismic activities, the analyses of the active faults, seismic activities and the sea floor unstable factors of the Zhujiang River Mouth Basin have been made so as to study the characteristics of the compressional subactive continental margin of Cathaysian system, arc littoral strongly active fracture zone, the division of seismic subzone and seismic zone of the continental margin of northern South China Sea, the potential focal area, and to analyze the regional stability. We consider that the Zhujiang River Mouth Basin belongs to a stable or a moderately stable region.
基金supported by the National Natural Science Foundation of China(No.42272222)the Basic Research Funds of Institute of Geomechanics,Chinese Academy of Geological Sciences(No.DZLXJK202211)China Geological Survey(Nos.DD20190306,DD20190546,DD20160269,DD20230249)。
文摘The 1605 M7½ Earthquake is the only earthquake in the history of China that has caused large-scale land subsidence into the sea,with the total area of land subsidence exceeding 100 km2.The disaster has led to the sinking of 72 villages.There is still no clear understanding of the source seismogenic fault of this earthquake.In this work,we conducted a detailed study of the middle segment of the Maniao-Puqian fault(MPF),which is the epicenter area,through geomorphological survey,data collection,shallow seismic exploration,cross-section drilling,and chronological dating.The results showed that the middle segment of the MPF zone is composed of three nearly parallel normal faults with a dextral strike-slip:“Macun-Luodou fault(F2-1),Haixiu-Dongyuan fault(F2-2),and ChangliuZhuxihe fault(F2-3)”.And F2-2 is composed of two secondary faults,namely F2-2′and F2-2″,with a flower-shaped structure buried under the ground.It is distributed nearly east-west,dipping to the north and has experienced at least five stages of activities since the Miocene.The vertical activity rates of F2-2′and F2-2″are~2.32 and~2.5 mm/a,since the Holocene,respectively.There were eight cycles of transgression and regression since the Miocene.The fault activity resulted in the thickening of the Holocene strata with a slight dip to the south,on the hanging wall,showing V-shaped characteristics.The MPF is likely the source seismogenic fault of the M7½ earthquake that hit Qiongshan in 1605.
基金supported by research grant from Institute of Crustal Dynamics,China Earthquake Administration(No.ZDJ2009-06)special research grant from Institute of Crustal Dynamics,China Earthquake Administration(No.ZDJ2007-01)
文摘On the basis of a 3-dimension visco-elastic finite element model of lithosphere in North China, we numerically simulate the recent mutative figures of tectonic stress field. Annual change characteristics of stress field are： 1 ） Maximum principal tensile stress is about 3 -9 kPaa-1 and its azimuth lie in NNW-SSE. 2） Maximum principal compressive stress is about 1 - 6 kPaa-1 and its azimuth lie in NEE-SWW. 3 ） Maximum principal tensile stress is higher both in the west region and Liaoning Province. 4） Variation of tectonic stress field benefits fault movement in the west part and northeast part of North China. 5 ）Annual accumulative rates of Coulomb fracture stress in Tanlu fault belt have segmentation patterns： Jiashan-Guangji segment is the high- est （6 kPaa - 1 ） , Anshan-Liaodongwan segment is the second （5 kPaa - l ） , and others are relatively lower （ 3 - 4 kPaa-1 ）.
基金sup-ported by the National Natural Science Foundation of China(Nos.41530963,91858215 and 41906048)the Fundamental Research Funds for the Central Universities(No.201964015)the Laboratory for Marine Mineral Resources,Qingdao National Laboratory for Marine Science and Technology(No.MMRZZ201801).
文摘The Ying-Qiong Basin is located on the northwestern margin of the South China Sea and at the junction of the South China Block and the Indochina Block.It is characterized by complex geological structures.The existing seismic data in the study area is sparse due to the lack of earthquake activities.Because of the limited source energy and poor coverage of seismic data,the knowledge of deep structures in the area,including the spatial distribution of deep faults,is incomplete.Contrarily,satellite gravity data cover the entire study area and can reveal the spatial distribution of faults.Based on the wavelet multi-scale decomposition method,the Bouguer gravity field in the Ying-Qiong Basin was decomposed and reconstructed to obtain the detailed images of the first-to sixth-order gravitational fields.By incorporating the known geological features,the gravitational field responses of the main faults in the Ying-Qiong Basin were identified in the detailed fields,and the power spectrum analysis yielded the depths of 1.4,8,15,26.5,and 39 km for the average burial depths of the bottom surfaces from the first-to fifth-order detailed fields,respectively.The four main faults in the Yinggehai Basin all have a large active depth range:fault A(No.1)is between 5 and 39 km,fault B is between 26.5 and 39 km,and faults C and D are between 15 and 39 km.However,the depth of active faults in the Qiongdongnan Basin is relatively shallow,mainly between 8 and 26.5 km.
基金supported by the Key Project of Chinese Programs for Fundamental Research and Development (2004CB418406)
文摘The Wenchuan earthquake coseismic deformation field is inferred from the coseismic dislocation data based on a 3-D geometric model of the active faults in Sichuan-Yunnan region. Then the potential dislocation displacement is inverted from the deformation field in the 3-D geometric model. While the faults＇ slip velocities are inverted from GPS and leveling data, which can be used as the long-term slip vector. After the potential dislocation displacements are projected to long-term slip direction, we have got the influence of Wenchuan earthquake on active faults in Sichuan-Yunnan region. The results show that the northwestern segment of Longmenshan fault, the southern segments of Xianshuihe fault, Anninghe fault, Zemuhe fault, northern and southern segments of Daliangshan fault, Mabian fault got earthquake risks advanced of 305, 19, 12, 9.1 and 18, 51 years respectively in the eastern part of Sichuan and Yunnan. The Lijiang-Xiaojinhe fault, Nujiang fault, Longling-Lancang fault, Nantinghe fault and Zhongdian fault also got earthquake risks advanced in the western part of Sichuan-Yunnan region. Whereas the northwestern segment of Xianshuihe fault and Xiaojiang fault got earthquake risks reduced after the Wenchuan earthquake.
基金State Key Basic Research Development and Programming Project (G19980407-04) and the Project during the ninth Five-Year Plan of Gansu Province (GK973-2-110A).
文摘Lanzhou Institute of Seismology, China Seismological Bureau, Lanzhou 730000, China 2) Institute of Geology, China Seismological Bureau, Beijing 100029, China
文摘The Lajishan Mountain fault zone consists of two NE_protruding arcuate faults, i.e. the northern and southern margin fault of Lajishan Mountain with the fault length of 230km and 220km respectively. The fault zone is located in the large_scale compressional structure zone and tectonic gradient zone in_between the NNW_trending right_lateral strike_slip Reshui_Riyueshan fault zone and the NWW_trending left_lateral strike_slip northern margin of west Qinling Ranges fault zone is also an important boundary fault zone, separating the Xining_Minhe basin and the Xunhua_Hualong basin at the southern and northern sides of the Lajishan Mountain respectively. Geologic geomorphic evidences of new activity revealed by field investigations indicate that the latest movement of the Lajishan fault zone was in late Epipleistocene (only a few segments were active in early Holocene) and is mainly of compressive thrusting with slightly left_lateral strike_slip component. The above movement has possibly resulted in the occurrence of about 20 moderate earthquakes of magnitude around 5.0. The Lajishan region can therefore be regarded as a seismotectonic window to reflect tectonic movement and earthquake activity.
基金This project was sponsored by National Development and Reform Commission (NDRC) on studies of experimental exploration of active fault in urban area(20041138)
文摘On the basis of the Xining active urban fault survey, we studied the relationship between the active urban fault and fold deformation. The result of this research shows that the Huangshuihe fault and the NW-striking fault on the northern bank of the Huangshulbe River are tensional faults on top of an anticline, the Nanchuanhe fault is a transverse tear fault resulting from differential folding on two sides of the fault, the east bank of the Beichuanhe River fault is a compressional fault developed on the core or climb of a syncline. By balance profile analysis of fold deformation and inversion of gravity anomaly data, we obtained the depth of the detachment plane and established the seismotectonic model of the ）fining urban area. Based on the seismotectonic model, we analyzed the earthquake potential of the active urban fault.
基金supported by the National Science Foundation of China (grant No. 41472204)
文摘Objective The lateral extrusion eastward of the Tibetan Plateau leads to the formation of the Sichuan–Yunnan block, which is the most representative active block in the southeastern margin of the Tibetan Plateau, characterized by strong and frequent seismicity(Li Ping et al., 1975; Zhang Peizhen et al., 2003; Li Yong et al., 2017). Its eastern boundary is composed of sinistral faults including the Xianshuihe, Xiaojiang faults, etc., and the western
