0 INTRODUCTION.According to the China Earthquake Networks Center,an M6.8 earthquake struck Dingri County,Xizang Autonomous Region,China,on 7 January 2025 at 9:05 a.m.local time.The epicenter is located at 28.5°N,...0 INTRODUCTION.According to the China Earthquake Networks Center,an M6.8 earthquake struck Dingri County,Xizang Autonomous Region,China,on 7 January 2025 at 9:05 a.m.local time.The epicenter is located at 28.5°N,87.45°E,with a depth of~10 km.展开更多
On December 18,2023,a Mw6.1 earthquake struck Jishishan County,Gansu Province,China,marking the most significant earthquake in the northeastern edge of the Tibetan Plateau since 2000.Given its proximate to the Loess P...On December 18,2023,a Mw6.1 earthquake struck Jishishan County,Gansu Province,China,marking the most significant earthquake in the northeastern edge of the Tibetan Plateau since 2000.Given its proximate to the Loess Plateau,which is extremely susceptible to geohazards,this earthquake raises awareness about the seismic hazard of several mega-cities such as Xi'an in Northwest China.In this paper,we inferred that the rupture occurred on an east-dipping backthrust,resulting from the regional E-W contraction tectonic setting.Our dynamic model through teleseismic waves and static model through radar displacement measurements together reveal a unilateral,along-strike rupture,encountering a slip barrier at one side of the main slip patch causing a cluster of aftershocks.We also identified a high-dip structure,which is an early-stage backthrust fault whose dip becomes increasingly high due to regional compressional tectonism.Apart from the loaded fault segments,particularly on the fault linkage,which necessitate continuous examination,a detailed seismic hazard assessment of the west Qinling and Daotanghe-Linxia fault system identifies a seismic gap between Weiyuan and Dingxi with the potential for a Mw7.5 earthquake.Collectively,these findings provide valuable insights into the seismic behavior of the seismogenic fault as well as guidance on hazard mitigation in its surrounding fault systems.展开更多
On 21 May 2021(UTC),an MW 7.4 earthquake jolted the east Bayan Har block in the Tibetan Plateau.The earthquake received widespread attention as it is the largest event in the Tibetan Plateau and its surroundings since...On 21 May 2021(UTC),an MW 7.4 earthquake jolted the east Bayan Har block in the Tibetan Plateau.The earthquake received widespread attention as it is the largest event in the Tibetan Plateau and its surroundings since the 2008 Wenchuan earthquake,and especially in proximity to the seismic gaps on the east Kunlun fault.Here we use satellite interferometric synthetic aperture radar data and subpixel offset observations along the range directions to characterize the coseismic deformation of the earthquake.Range offset displacements depict clear surface ruptures with a total length of~170 km involving two possible activated fault segments in the earthquake.Coseismic modeling results indicate that the earthquake was dominated by left-lateral strike-slip motions of up to 7 m within the top 12 km of the crust.The well-resolved slip variations are characterized by five major slip patches along strike and 64%of shallow slip deficit,suggesting a young seismogenic structure.Spatial-temporal changes of the postseismic deformation are mapped from early 6-day and 24-day InSAR observations,and are well explained by time-dependent afterslip models.Analysis of Global Navigation Satellite System(GNSS)velocity profiles and strain rates suggests that the eastward extrusion of plateau is diffusely distributed across the east Bayan Har block,but exhibits significant lateral heterogeneities,as evidenced by magnetotelluric observations.The block-wide distributed deformation of the east Bayan Har block along with the significant co-and post-seismic stress loadings from the Madoi earthquake imply high seismic risks along regional faults,especially the Tuosuo Lake and Maqên-Maqu segments of the Kunlun fault that are known as seismic gaps.展开更多
In March 2021,a seismic sequence including three Mw>5.5 events struck northern Thessaly,Greece.Owing to the high temporal resolution of Sentinel-1 images which were sampled every 6 days and recorded the three event...In March 2021,a seismic sequence including three Mw>5.5 events struck northern Thessaly,Greece.Owing to the high temporal resolution of Sentinel-1 images which were sampled every 6 days and recorded the three events separately,we are able to map individually the coseismic deformation fields of the three events.Based on their respective coseismic displacements,we determined the geometry of the fault plane for each earthquake with the method of multipeak particle swarm optimization and inverted the best-fitting slip distribution by linear least squares inversion.Modelling results show that the three events occurred successively on 3,4 and 12 March 2021 were all dominated by normal-slip motions on previously unknown faults within the top 15 km of the Earth’s crust.The 3 March 2021 Mw 6.3 earthquake ruptured a northeast-dipping fault with a strike angle of 301°(clockwise from the North)and a dip angle of 46°,producing the maximum slip of about 2.2 m.The slip motion of the 4 March 2021 Mw 5.9 aftershock shows a similar fault geometry(striking 297°and dipping 42°)to the 3 March mainshock,but with a considerably smaller dip-slip component(~0.8 m).The 12 March 2021 Mw 5.6 aftershock occurred on a southwest-dipping fault(striking 100°and dipping 40°)with a normal fault slip of up to 0.5 m.Static Coulomb stress changes triggered by the earthquake sequence imply a promotion relationship between the first 3 March event and the two subsequent events.Due to the coseismic stress perturbation,more than 70%of aftershocks were distributed in areas with increased Coulomb stress and the northwest segment of the Larissa fault close to the seismic sequence was exposed to a relatively high seismic risk.展开更多
High-elevation and long-runout landslides are among the most destructive mountain hazards.In this study,we present the first identification of a high-elevation and long-runout landslide,referred to as the Guba landsli...High-elevation and long-runout landslides are among the most destructive mountain hazards.In this study,we present the first identification of a high-elevation and long-runout landslide,referred to as the Guba landslide,located near the Jinsha River Bridge,using interferometric synthetic aperture radar(InSAR)technology.This landslide poses a significant threat to the construction and future safe operation of both the Jinsha River Bridge and the Yebatan hydropower station.Therefore,deformation monitoring and risk assessment based on comprehensive remote sensing and numerical simulation are urgently required.We processed SAR imagery acquired from four satellite platforms between July 2007 and September 2023 to derive surface displacements of the Guba landslide.A topography-constrained model integrating multi-track SAR observations was employed to retrieve the three-dimensional deformation field and determine the optimal sliding direction for each pixel,enabling estimation of the potential slip surface.Furthermore,a Tikhonov regularization method was applied to reconstruct a nearly 16-year displacement time series along the sliding direction.To assess potential hazards,numerical simulations were conducted to estimate the extent and impact of possible landslide failures.Results show that the Guba landslide is a large-scale rockslide with an area of approximately 0.17 km^(2),a maximum slip surface depth of 94 m,and an estimated volume of 0.84×10^(7)m^(3).The cumulative displacement of the landslide between 2007 and 2023 reached 1.37 m,and it is currently in an initial accelerated subphase.Numerical simulation results suggest that once failed,the landslide mass could move rapidly along the valley,forming a debris dam approximately 40–50 m high and 200 m wide across the Jinsha River,which poses a severe risk to both the bridge and the hydropower station.In addition,local seasonal deformation oscillations were observed,potentially driven by the coupled effects of precipitation and near-surface temperature.Further wavelet analysis revealed a time lag of approximately 39 days between deformation,rainfall,and near-surface temperature.These findings offer critical insights into the mitigation and management of the Guba landslide,supporting the safe implementation of major infrastructure projects.Moreover,the approach provides a novel framework for investigating high-elevation and long-runout landslides in inaccessible mountainous regions.展开更多
基金funded by the National Key R&D Program of China(No.2020YFC150071)partly supported by the Shaanxi Province Geoscience Big Data and Geohazard Prevention Innovation Team(2022)and the Research Funds for the Interdisciplinary Projects,CHU(No.300104240914)。
文摘0 INTRODUCTION.According to the China Earthquake Networks Center,an M6.8 earthquake struck Dingri County,Xizang Autonomous Region,China,on 7 January 2025 at 9:05 a.m.local time.The epicenter is located at 28.5°N,87.45°E,with a depth of~10 km.
基金funded by the National Natural Science Foundation of China(No.42377159)the Shaanxi Province Science and Technology Innovation Team(No.2021TD-51)+1 种基金the Shaanxi Province Geoscience Big Data and Geohazard Prevention Innovation Team(2022)the Fundamental Research Funds for the Central Universities,CHD(No.300102263401)。
文摘On December 18,2023,a Mw6.1 earthquake struck Jishishan County,Gansu Province,China,marking the most significant earthquake in the northeastern edge of the Tibetan Plateau since 2000.Given its proximate to the Loess Plateau,which is extremely susceptible to geohazards,this earthquake raises awareness about the seismic hazard of several mega-cities such as Xi'an in Northwest China.In this paper,we inferred that the rupture occurred on an east-dipping backthrust,resulting from the regional E-W contraction tectonic setting.Our dynamic model through teleseismic waves and static model through radar displacement measurements together reveal a unilateral,along-strike rupture,encountering a slip barrier at one side of the main slip patch causing a cluster of aftershocks.We also identified a high-dip structure,which is an early-stage backthrust fault whose dip becomes increasingly high due to regional compressional tectonism.Apart from the loaded fault segments,particularly on the fault linkage,which necessitate continuous examination,a detailed seismic hazard assessment of the west Qinling and Daotanghe-Linxia fault system identifies a seismic gap between Weiyuan and Dingxi with the potential for a Mw7.5 earthquake.Collectively,these findings provide valuable insights into the seismic behavior of the seismogenic fault as well as guidance on hazard mitigation in its surrounding fault systems.
基金supported by the Natural Science Foundation of Jiangsu Province(Grant No.SBK2020043202)by Key Laboratory of Geospace Environment and Geodesy,Ministry of Education,Wuhan University(No.19-01-08).
文摘On 21 May 2021(UTC),an MW 7.4 earthquake jolted the east Bayan Har block in the Tibetan Plateau.The earthquake received widespread attention as it is the largest event in the Tibetan Plateau and its surroundings since the 2008 Wenchuan earthquake,and especially in proximity to the seismic gaps on the east Kunlun fault.Here we use satellite interferometric synthetic aperture radar data and subpixel offset observations along the range directions to characterize the coseismic deformation of the earthquake.Range offset displacements depict clear surface ruptures with a total length of~170 km involving two possible activated fault segments in the earthquake.Coseismic modeling results indicate that the earthquake was dominated by left-lateral strike-slip motions of up to 7 m within the top 12 km of the crust.The well-resolved slip variations are characterized by five major slip patches along strike and 64%of shallow slip deficit,suggesting a young seismogenic structure.Spatial-temporal changes of the postseismic deformation are mapped from early 6-day and 24-day InSAR observations,and are well explained by time-dependent afterslip models.Analysis of Global Navigation Satellite System(GNSS)velocity profiles and strain rates suggests that the eastward extrusion of plateau is diffusely distributed across the east Bayan Har block,but exhibits significant lateral heterogeneities,as evidenced by magnetotelluric observations.The block-wide distributed deformation of the east Bayan Har block along with the significant co-and post-seismic stress loadings from the Madoi earthquake imply high seismic risks along regional faults,especially the Tuosuo Lake and Maqên-Maqu segments of the Kunlun fault that are known as seismic gaps.
基金National Key Research and Development Program of China(No.2019YFC1509201)Chinese Scholarship Council Studentship(No.201806270247)+3 种基金Shaanxi Province Science and Technology Innovation Team(No.2021TD-51)UK Natural Environment Research Council through the Centre for the Observation and Modeling of Earthquakes,Volcanoes and Tectonics(No.come30001)LICS Project(No.NE/K010794/1)European Space Agency through the ESA-MOST DRAGON-5 Project(No.59339)。
文摘In March 2021,a seismic sequence including three Mw>5.5 events struck northern Thessaly,Greece.Owing to the high temporal resolution of Sentinel-1 images which were sampled every 6 days and recorded the three events separately,we are able to map individually the coseismic deformation fields of the three events.Based on their respective coseismic displacements,we determined the geometry of the fault plane for each earthquake with the method of multipeak particle swarm optimization and inverted the best-fitting slip distribution by linear least squares inversion.Modelling results show that the three events occurred successively on 3,4 and 12 March 2021 were all dominated by normal-slip motions on previously unknown faults within the top 15 km of the Earth’s crust.The 3 March 2021 Mw 6.3 earthquake ruptured a northeast-dipping fault with a strike angle of 301°(clockwise from the North)and a dip angle of 46°,producing the maximum slip of about 2.2 m.The slip motion of the 4 March 2021 Mw 5.9 aftershock shows a similar fault geometry(striking 297°and dipping 42°)to the 3 March mainshock,but with a considerably smaller dip-slip component(~0.8 m).The 12 March 2021 Mw 5.6 aftershock occurred on a southwest-dipping fault(striking 100°and dipping 40°)with a normal fault slip of up to 0.5 m.Static Coulomb stress changes triggered by the earthquake sequence imply a promotion relationship between the first 3 March event and the two subsequent events.Due to the coseismic stress perturbation,more than 70%of aftershocks were distributed in areas with increased Coulomb stress and the northwest segment of the Larissa fault close to the seismic sequence was exposed to a relatively high seismic risk.
基金supported by the National Natural Science Foundation of China(Grant No.41941019)the Shaanxi Province Science and Technology Innovation Team(Grant No.2021TD-51)+2 种基金the Shaanxi Province Geoscience Big Data and Geohazard Prevention Innovation Team(Grant No.2022)ESA-MOST China DRAGON-6 project(Grant No.95355)the Fundamental Research Funds for the Central Universities,CHD(Grant Nos.300102260301 and 300102261108)。
文摘High-elevation and long-runout landslides are among the most destructive mountain hazards.In this study,we present the first identification of a high-elevation and long-runout landslide,referred to as the Guba landslide,located near the Jinsha River Bridge,using interferometric synthetic aperture radar(InSAR)technology.This landslide poses a significant threat to the construction and future safe operation of both the Jinsha River Bridge and the Yebatan hydropower station.Therefore,deformation monitoring and risk assessment based on comprehensive remote sensing and numerical simulation are urgently required.We processed SAR imagery acquired from four satellite platforms between July 2007 and September 2023 to derive surface displacements of the Guba landslide.A topography-constrained model integrating multi-track SAR observations was employed to retrieve the three-dimensional deformation field and determine the optimal sliding direction for each pixel,enabling estimation of the potential slip surface.Furthermore,a Tikhonov regularization method was applied to reconstruct a nearly 16-year displacement time series along the sliding direction.To assess potential hazards,numerical simulations were conducted to estimate the extent and impact of possible landslide failures.Results show that the Guba landslide is a large-scale rockslide with an area of approximately 0.17 km^(2),a maximum slip surface depth of 94 m,and an estimated volume of 0.84×10^(7)m^(3).The cumulative displacement of the landslide between 2007 and 2023 reached 1.37 m,and it is currently in an initial accelerated subphase.Numerical simulation results suggest that once failed,the landslide mass could move rapidly along the valley,forming a debris dam approximately 40–50 m high and 200 m wide across the Jinsha River,which poses a severe risk to both the bridge and the hydropower station.In addition,local seasonal deformation oscillations were observed,potentially driven by the coupled effects of precipitation and near-surface temperature.Further wavelet analysis revealed a time lag of approximately 39 days between deformation,rainfall,and near-surface temperature.These findings offer critical insights into the mitigation and management of the Guba landslide,supporting the safe implementation of major infrastructure projects.Moreover,the approach provides a novel framework for investigating high-elevation and long-runout landslides in inaccessible mountainous regions.
