0 INTRODUCTION.The global availability of digital elevation model(DEM)data,such as 90-m Shuttle Radar Topography Mission(SRTM)DEM and 30-m Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital ...0 INTRODUCTION.The global availability of digital elevation model(DEM)data,such as 90-m Shuttle Radar Topography Mission(SRTM)DEM and 30-m Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Model(ASTER GDEM),has been extensively utilized in morphotectonic analyses(e.g.,Wang et al.,2024;Cheng et al.,2018;Pérez-Pe?a et al.,2010;El Hamdouni et al.,2008).展开更多
The Longchuan River basin lies within the China Sichuan-Yunnan rhomboid block.The NS-trending Yuanmou-Lvzhi River Fault(YLF),NW-trending Chuxiong-Nanhua Fault(CNF)and Shiyang-Huoshaotun Fault(HSF)are found within the ...The Longchuan River basin lies within the China Sichuan-Yunnan rhomboid block.The NS-trending Yuanmou-Lvzhi River Fault(YLF),NW-trending Chuxiong-Nanhua Fault(CNF)and Shiyang-Huoshaotun Fault(HSF)are found within the basin.The nature of the faults is complex,and the tectonic activity distribution characteristics require further clarification.By extraction from a digital elevation model,the measured longitudinal profile and the geomorphic indices of the Longchuan River,basin showed a stream-length gradient index(SL)of 49–650,hypsometric integral(HI)of 0.27–0.58,drainage basin asymmetry factor(AF)of 3.29–27.47,basin shape index(BS)of 0.87–2.75,valley floor width-to-height ratio(VF)of 0.06–5.40,and evaluation of relative tectonic activity(Iat)of 1.6–2.6.Results showed that river morphology and geomorphological indices in the Longchuan River basin were influenced by tectonic activity,bedrock lithology,climatic conditions,and development time,with tectonic activity playing a dominant role.The relative tectonic activity of the Longchuan River basin was zoned,with a gradual increase in relative tectonic activity from the south to the north.That the slip fault zone primarily controls the tectonic deformation of the Longchuan River basin in central Yunnan and the dynamics of the central Yunnan massif are consistent with the“rigid block lateral extrusion”1model.展开更多
The West Anatolia Extensional Zone, which has a width of about 300 km, is located within the Alpine-Himalayan belt and is one of the regions with intense seismic activity in the world. The most important geomorphologi...The West Anatolia Extensional Zone, which has a width of about 300 km, is located within the Alpine-Himalayan belt and is one of the regions with intense seismic activity in the world. The most important geomorphological structures in this area are three main graben structures resulting from regional N-S extension since the Early Miocene. These structures are the E-W trending Büyük Menderes, Kü?ük Menderes, and Gediz grabens. S?ke Basin is located at the SW end of the Büyük Menderes graben. The lineaments which control the NW of S?ke Basin have a length of approximately 40 km and have been defined as the Priene-Sazl? Fault(PSF). The PSF is seismically active, and the last large earthquake(the S?ke-Balat earthquake; Ms: 6.8) was produced on July 16 th of 1955. The ancient city of Priene, which was located in the study area, suffered from destructive earthquakes(in the 4 th century and 2 nd century BC, in the 2 nd century AD, during the Byzantine period and after the 12 th century BC). This study aims to reveal the effect of the PSF on the morphotectonic evolution of the region and the relative tectonic activity of the fault. To this end, it was the first time the stream length gradient index(SL: 130-1303), mountain-front sinuosity(Smf: 1.15-1.96), valley floor height and valley width ratio(Vf: 0.27-1.66), drainage basin asymmetry(AF: 0.15-0.76), hypsometric curve(HC) and hypsometric integral(HI: 0.22-0.86) and basin shape index(Bs: 1.04-5.75) along the mountain front that is formed by the PSF. Using a combination of the mountain-front sinuosity(Smf), valley floor height and valley width ratio(Vf), it is found that the uplift ratio in the region is not less than 0.05 mm/yr and the relative tectonic activity of PSF is high. According to the relative tectonic activity index(Iat) obtained from geomorphic indices, the southwest part of the PSF is relatively more active than the northeast part. As a result, I posit that the PSF has the potential to produce earthquakes in the future similarly to those that were produced in the past, and that the most destructive earthquakes will likely occur on the southwest segments of the fault according to geomorphic indices.展开更多
The eastern Tibetan plateau has been getting more and more attention because it combines active faults,uplifting, and large earthquakes together in a high-population region. Based on the previous researches, the most ...The eastern Tibetan plateau has been getting more and more attention because it combines active faults,uplifting, and large earthquakes together in a high-population region. Based on the previous researches, the most of Cenozoic tectonic activities were related to the regional structure of the local blocks within the crustal scale. Thus,a better understanding of the crustal structure of the regional tectonic blocks is an important topic for further study. In this paper, we combined the simple Bouguer gravity anomaly with the Moho depths from previous studies to investigate the crustal structure in this area. To highlight the crustal structures, the gravity anomaly caused by the Moho relief has been reduced by forward modeling calculations. A total horizontal derivative（THD） had been applied on the gravity residuals. The results indicated that the crustal gravity residual is compatible with the topography and the geological settings of the regional blocks,including the Sichuan basin, the Chuxiong basin, the Xiaojiang fault, and the Jinhe fault, as well as the Longmenshan fault zone. The THD emphasized the west margin of Yangtze block, i.e., the Longriba fault zone and the Xiaojiang fault cut through the Yangtze block. The checkboard pattern of the gravity residual in the SongpanGarze fold belt and Chuandian fragment shows that the crust is undergoing a southward and SE-directed extrusion,which is coincident with the flowing direction indicatedfrom the GPS measurements. By integrating the interpretations, the stepwise extensional mechanism of the eastern Tibetan plateau is supported by the southeastward crustal deformation, and the extrusion of Chuandian fragment is achieved by Xianshuihe fault.展开更多
This paper tests a data mining method for evaluation of the ＂IRTA＂（Index of Relative Tectonic Activity） to investigate the impact of active tectonics on geomorphic processes and landscape development. Based upon K...This paper tests a data mining method for evaluation of the ＂IRTA＂（Index of Relative Tectonic Activity） to investigate the impact of active tectonics on geomorphic processes and landscape development. Based upon K-means clustering of six basin-related geomorphic indices（the hypsometric integral, basin asymmetric factor, drainage density, basin shape ratio, mean axial slope of the channel and topographic roughness） that represent the relative strength of active tectonic deformation on topography and morphology, the relative tectonic activity along the Kazerun Fault Zone in the Zagros Mountains of Iran may be classified into low, moderate and high relative tectonic activity zones. The results allow the identification of the clusters of similarly deformed areas related to relative tectonic activity. The utilization of geomorphic parameters as well as IRTA with comparison to the field observations exhibit change in relative tectonic activities mostly corresponding to the change in mechanism of the prominent fault zones in the study area.展开更多
Decoupling between climate and tectonics, transform the elevation of earth surface regionally by denudation and displacement of land. To extract the tectonic footprints on morphology of landform, geormophometry is wid...Decoupling between climate and tectonics, transform the elevation of earth surface regionally by denudation and displacement of land. To extract the tectonic footprints on morphology of landform, geormophometry is widely accepted tool due to visible responses in Drainage architecture to an intense tectonic environment. The present morphology of Yamuna basin in the Garhwal Himalaya, India is a result of continuing crustal deformation;erosion and deposition in the area. The drainage system and geomorphic expression of topography have been significantly influenced by active tectonics in this basin. In present study, for numerical modelling to detect the influence of tectonic signals on landform, we used morphotectonic parameters, to gradient index (SL), valley floor height to width ratio (Vf), asymmetry factor (Af), basin shape index (BS) and hypsometric integral (HI), extracted from SRTM DEM with resolution of 30 m. All these morphotectonic parameters are integrated to produce an index of relative active tectonics (IRAT). The Yamuna basin is classified into three groups based on IRAT, very high (<2.0);moderate (2.0 - 2.25) and low (>2.25) based on the degree of tectonic activity. Result shows approx. 56% of Yamuna basin experience high tectonic activity. This along strike deformation pattern pronouncedly emulates subsurface geometry based tectonic model.展开更多
Tectonic activities significantly impact deep reservoir properties via sedimentary and diagenetic processes,and this is particularly true for lacustrine rift basins.The tectonic-sedimentary-diageneticreservoir system ...Tectonic activities significantly impact deep reservoir properties via sedimentary and diagenetic processes,and this is particularly true for lacustrine rift basins.The tectonic-sedimentary-diageneticreservoir system is crucial in deep reservoir exploration.This study examined the first member and upper submember of the second member of the Dongying Formation in the Bodong Low Uplift in the Bohai Bay Basin(East China),documenting the petrologic features and physical properties of reservoirs in different tectonic sub-units through integrated analysis of log and rock data,along with core observation.A mechanism for deep reservoir formation in lacustrine rift basins was developed to elucidate the sedimentary and diagenetic processes in complex tectonic settings.The results show that tectonic activities result in the occurrence of provenances in multiple directions and the existence of reservoirs at varying burial depths,as well as the significant diversity in sedimentary and diagenetic processes.The grain sizes of the sandstones,influenced by transport pathways rather than the topography of the sedimentary area,exhibit spatial complexity due to tectonic frameworks,which determine the initial pore content of reservoirs.However,the burial depth,influenced by subsequent tectonic subsidence,significantly impacts pore evolution during diagenesis.Based on the significant differences of reservoirs in slope zone,low uplift and depression zone,we establish different tectonic-diagenetic models in deep complex tectonic units of lacustrine rift basins.展开更多
Previous studies have indicated that sediment gravity flow deposits developed in lacustrine active extensional rift basins are primarily influenced by tectonics and to a lesser extent by climate.Our present work revea...Previous studies have indicated that sediment gravity flow deposits developed in lacustrine active extensional rift basins are primarily influenced by tectonics and to a lesser extent by climate.Our present work reveals that climate can obscure the effect of tectonic subsidence by regulating sediment supply;conversely,tectonics can impede the sedimentary manifestation of climatic impacts.Here a case study has been presented to assess the impact of climate-modulated rapid lake-level rise and tectonic subsidence on the development of coarse-grained gravity flow deposits in the Dongying rift margin of the Bohai Bay Basin,eastern China.The lithofacies analysis reveals frequent bed amalgamation,abundant thick massive coarse-grained deposits,widespread cross bedding and plant fragments,and incomplete composite bed formed by high-energy erosion,indicating that the hyperpycnal flow is an important mechanism driving the deposition of these coarse-grained sediments.Detailed sequence stratigraphic analysis and sediment dispersal pattern suggest that the long-striped nearshore subaqueous fan systems induced by outburst-flood hyperpycnal flow distributed along the border fault,are primarily controlled by long-term tectonics,while the rapid rise of lake level driven by short-term climate change possibly intensifies seasonal flood-generated hyperpycnal flow occurrences and consequently promotes the basinal fan progradation.The maximum scale of these coarse-grained gravity flow deposits of the basinal fan systems are typically attained during the transgressive systems tract,which deviates from the classical sequence stratigraphic model.Furthermore,it presented a continuous transition from the proximal to the distal part,encompassing traction flows and turbidity currents during the periods of relatively stable tectonics.Nevertheless,gravel-rich debris flows appear to predominate the dispersion of coarse-grained sediments during periods characterized by intense tectonic activity.The coarse-grained gravity flow deposits in the lacustrine rift margin reported here,challenge the traditional beliefs:this study suggests that subaqueous deposits abundantly preserved in the transgressive setting.展开更多
Understanding the active tectonic processes in the Nandakini Watershed is imperative for evaluating geological hazards and seismic risks,as well as for informing land-use planning and natural resource management strat...Understanding the active tectonic processes in the Nandakini Watershed is imperative for evaluating geological hazards and seismic risks,as well as for informing land-use planning and natural resource management strategies in the region.Tectonic geomorphology serves as a vital tool for characterizing recent tectonic movements.This research employs GIS techniques to elucidate tectonic activity and its influence on drainage patterns in the Nandakini Watershed,utilizing morphometric parameters derived from SRTM DEM data.Morphometric indices are employed to assess the tectonic movement within drainage basins,capturing both areal and linear factors such as drainage density,texture,circulatory and bifurcation ratios,and stream length ratios.The linear and areal morphometric indices are categorized into three classes representing varying degrees of active tectonic activity.These classifications are then utilized to compute the relative active tectonic index(IRAT).In addition,geomorphic parameters include hypsometric integral,stream length-gradient index,normalized steepness index,chi gradient index,and swath profiles.The majority of the studied region is in an extremely high to moderately active tectonic zone.Large-scale faults and thrusts within the basins are closely correlated with these zones that have been identified.The integrated methodology of GIS-based morphometric analysis and geomorphic study enables the identification of deformed landforms associated with ongoing tectonic activity.Furthermore,these results offer valuable insights for informing watershed management strategies and promoting sustainable land use planning initiatives.展开更多
This research investigates dynamic earth processes within the South Setifian allochthonous ensemble,providing insights into landscape evolution and seismotectonic activity within the Tellian mountain chain.Focusing on...This research investigates dynamic earth processes within the South Setifian allochthonous ensemble,providing insights into landscape evolution and seismotectonic activity within the Tellian mountain chain.Focusing on the Jebel Gustar and Kef Lahmar area,which includes 14 sub-basins,this research uses a DEM-based technique to assess Holocene activities,lineament characteristics,and stream systems.Five geomorphic indices are used to assess relative active tectonics:the stream lengthgradient index(SL),drainage basin asymmetry(AF),valley-floor width to valley height ratio(VF),drainage basin shape(BS),and mountain front sinuosity(SMF).A weighted overlay of these five indices produces the Index of Relative Active Tectonics(IRAT)map.The findings reveal significant neotectonic activity in the study area,supported by profound basement faulting.This research highlights the morpho-structural processes and neotectonics activity in the Jebel Gustar,providing a framework for investigating the evolution of this structure.Additionally,it enhances comprehension of the interactions between the alpine range's internal zones in Eastern Algeria and the Atlasic domain.This study proposes a systematic approach to evaluate the tectonic and geomorphological dynamics of the South Setif region.展开更多
The use of satellite thermal infrared information is being developed as a method of exploring current tectonic activity. To realize real world application, an objective, stable and testable thermal physical index that...The use of satellite thermal infrared information is being developed as a method of exploring current tectonic activity. To realize real world application, an objective, stable and testable thermal physical index that is simultaneously related with tectonic activity must be established. From the viewpoint of the energy balance, the land surface is a boundary where energy is exchanged between outer space and the solid Earth. Regardless of how complex the influencing factors are, the land surface is mainly affected by the Sun, atmosphere and underground heat. In this paper, first, the relationships among land surface temperature, solar radiation, atmospheric temperature and thermal information from underground are obtained employing a mathematic physical method based on the equation of heat conduction and energy balance at the land surface. Second, a thermal physical index called the geothermal flux index (GFI), which can provide the activity state of underground heat, is constructed. Third, the theoretical basis of the thermal physical index is verified using stable annual variations in land surface temperature and solar radiation. Finally, combined with known crustal deformations derived using a global positioning system, the effectiveness of the GFI in extracting field tectonic motion is tested. The results indicate that the GFI is effective in providing information on current tectonic activity.展开更多
Quantitative geomorphic analyses are usually powerful in identifying active tectonics across global orogenic belts.Our present study will focus on the Anatolian Plate which hosts a lot of recent catastrophic earthquak...Quantitative geomorphic analyses are usually powerful in identifying active tectonics across global orogenic belts.Our present study will focus on the Anatolian Plate which hosts a lot of recent catastrophic earthquakes in Türkiye.Six geomorphic indices for 100 sub-basins around Türkiye have been computed including local relief,slope,normalized steepness index(k_(Sn)),hypsometric curve and integral(HI),transverse topographic symmetry factor(Tf),and the basin asymmetry factor(Af).The averaged kSnand Af values have shown four high-value anomalous zones,suggesting relatively high uplift rates featured by high river incision and regional tilting.The values of 0.35≤HI<0.6 for basins with S-shaped curves imply intensive tectonic activities along the eastern part of the North Anatolian Fault Zone(NAFZ),the Northeast Anatolian Fault Zone(NEAFZ),the East Anatolian Fault Zone(EAFZ),and the Central Anatolian Fault Zone(CAFZ).All results of the geomorphic indices analysis suggest a relatively high degree of tectonic activity in the following four areas,the Isparta Angle,the Eastern Black Sea Mountains,the South-eastern Anatolia Region,and the Central Anatolian fault zone.We further suggest that the eastern part of the NAFZ,NEAFZ,EAFZ,and CAFZ will be more active in tectonic activities,with a greater potential for strong earthquake occurrence.展开更多
Based on the research and the division of the active tectonic blocks and their boundaries on the Chinese mainland, the feature of the large earthquake activities on the 24 boundaries between the 6 active tectonic bloc...Based on the research and the division of the active tectonic blocks and their boundaries on the Chinese mainland, the feature of the large earthquake activities on the 24 boundaries between the 6 active tectonic block regions (grade Ⅰ) and the 22 active tectonic blocks (grade Ⅱ) are studied. The seismicity levels on the active tectonic block boundaries are discussed considering the large earthquake frequency and the released strain energy in unit distance and time. The theoretic maximal magnitude and the recurrence period of each boundary are then calculated from the G-R relation. By comparing this with the actual earthquake records, it is found that the intensities of the earthquake deduced from the seismic activity parameter (a/b) on the main active boundaries on the Chinese mainland are consistent with that of the natural earthquakes. Meanwhile, an inverse relation is found between the recurrence periods of large earthquakes and the tectonic motion rate on the boundaries. These results show that the a, b values of each boundary obtained in this paper are valuable. In addition, the present seismic activities and hazards of these boundaries are also probed into with the historical data and their elapsed time on each boundary based on the hypothesis that the large earthquakes satisfy Poisson distribution.展开更多
Based on the hypothesis of the active tectonic blocks on the Chinese continent and its adjacent regions (both the method of the DDA on a spherical surface and the GPS survey results observed from 1991 to 2001 are used...Based on the hypothesis of the active tectonic blocks on the Chinese continent and its adjacent regions (both the method of the DDA on a spherical surface and the GPS survey results observed from 1991 to 2001 are used), the movements and deformations of each active tectonic block are calculated. The calculation results show that although the movements and deformations of active tectonic blocks in the eastern region and in the western region of China are different, active tectonic blocks in the same active tectonic block region are coherent. Then, the relative velocities of the active tectonic blocks’ boundary zones are calculated, and the relationship between current crustal motion and strong seismic activities is discussed. Earthquakes ( M S≥7 0) on the Chinese continent since 1988 all occurred on boundary zones of active tectonic blocks with high slipping speed.展开更多
Active tectonics in an area includes ongoing or recent geologic events.This paper investigates the tectonic influence on the subsidence,uplift and tilt of western Saurashtra through morphotectonic analysis of ten wate...Active tectonics in an area includes ongoing or recent geologic events.This paper investigates the tectonic influence on the subsidence,uplift and tilt of western Saurashtra through morphotectonic analysis of ten watersheds along with characteristics of relief and drainage orientation.Watersheds 7-9 to the north(N)are tectonically active,which can be linked with the North Kathiawar Fault System(NKFS)and followed by watersheds 6,10,1,4 and 5.Stream-length gradient index and sinuosity index indicate the effect of tectonic events along the master streams in watersheds 6-9.Higher R^(2)values of the linear curve fit for watershed 7 indicate its master stream is much more tectonically active than the others.The R^(2)curve fitting model and earthquake magnitude/depth analysis confirm the region to be active.The reactivation of the NKFS most likely led to the vertical movement of western Saurashtra.展开更多
The Okinawa Trough is a very active tectonic zone at the margin of the Northwest Pacific and is typical of back arc rifting at the young stage of tectonic evolution. Many scientists from Japan, China, Germany, France,...The Okinawa Trough is a very active tectonic zone at the margin of the Northwest Pacific and is typical of back arc rifting at the young stage of tectonic evolution. Many scientists from Japan, China, Germany, France, the U.S.A. and Russia have done a lot of geologic and geophysical investigations there. It is well known that the Okinawa Trough is an active back arc rift with extremely high heat flow, very strong hydrothermal circulation, strong volcanic and magmatic activity, frequent earthquakes, rapid subsidence and rifting, well developed fault and central graben. But up to now, there are still some important tectonic problems about the Okinawa Trough that require clarification on some aspects such as the type of its crust, its forming time, its tectonic evolution, the distribution of its central grabens, the relationship between its high heat flow and tectonic activity. Based on the data obtained from seismic survey, geomagnetic and gravity measurements, submarine sampling and heat flow measurements in the last 15 years, the author discusses the following tectonic problems about the Okinawa Trough: (1) If the Okinawa Trough develops oceanic crust or not. (2) Is the South Okinawa Trough tectonically more active than the North Okinawa Trough with shallower water and few investigation data on it. (3) The formation time of the Okinawa Trough and its tectonic evolution. The Okinawa Trough has a very thin continental crust. Up to now, there is no evidence of oceanic crust in the Okinawa Trough. The North, Middle and South Okinawa Trough are all very strongly active areas. From 6 Ma B.P., the Okinawa Trough began to form. Since 2 Ma, the Okinawa Trough has been very active.展开更多
The Colca Valley in the Central Andes is a region characterized by the occurrence of large slow-moving landslides and a high level of seismic activity.In this study,we aimed to determine passive and active tectonic co...The Colca Valley in the Central Andes is a region characterized by the occurrence of large slow-moving landslides and a high level of seismic activity.In this study,we aimed to determine passive and active tectonic control on the formation of selected five large landslides in the Colca Valley and to assess geohazard associated with these features.For that purpose,we performed a post-landslide field survey,applied remote sensing techniques,and obtained eyewitness accounts.Recently,the need to understand mass movement processes in this region is even higher due to the establishment of the Colca y Volcanes de Andagua Geopark(Colca and Andagua Volcanoes Geopark).Our results suggest that the studied landslides usually represent a complex failure mechanism,dominated by translational sliding or rotational displacements,commonly associated with the formation of horst-and-graben like structures.We found a spatial correlation between the distribution of landslides and inherited fault network.The head scarps appear to be limited by the WNW-to NW-striking faults,whereas the lateral extent of some of the reported features seems to be connected with the NNE-striking normal faults,common in both,the Mesozoic strata and the Pleistocene-Holocene deposits.展开更多
Analysis on helium isotopes in natural gas in Bohai Bay Basin showed their mantle-origin indicated by high 3He/4He ratio. The span of 3He/4He ratio increased from west to east. This pattern im- plied a close relations...Analysis on helium isotopes in natural gas in Bohai Bay Basin showed their mantle-origin indicated by high 3He/4He ratio. The span of 3He/4He ratio increased from west to east. This pattern im- plied a close relationship to the local tectonic setting. Bohai Bay Basin experienced intensive neo-tectonic activities in the Cenozoic. Widespread faulted-depressions and strong volcanic eruptions manifested its extensional tectonics. Abiogenic natural gas could be released from magmas and migrate upward through deep faults during the extension. Tectonic conditions in the area would favor upward invasion and reser- vation of mantle-originated helium. Furthermore, with decrease of convergence rate between the Pacific and the Eurasia Plate, the subduction slab of the Pacific Plate rolled back and became steeper, resulting in mantle flow and other tectonic activities migrating from west to east in nature, and caused the variation in isotopic helium ratios.展开更多
Based on detailed field investigations, this paper describes the geometrical characteristics and tectonic activities of the Zhangjiakou fault at the northwest of Beijing. This fault strikes mainly northwest to west, s...Based on detailed field investigations, this paper describes the geometrical characteristics and tectonic activities of the Zhangjiakou fault at the northwest of Beijing. This fault strikes mainly northwest to west, short parts of which strike near east to west, dipping north, and extends over a length of 70km. It is a major geological and geomorphologicai margin, controlling the neotectonic movement in this region. On the south side of the Zhangjiakou fault are the Late Quaternary unconsolidated deposits, forming basins; while on the other side are Mesozoic volcano debris and Pre-Mesozoic metamorphic rocks, forming lower mountains and hills. The Zhangjiakou fault consists mainly of high-angle inverse strike-slip fault and partially of normal strike-slip fault. Among these, the north-dipping NW-NWW-trending secondary faults, constituting the main fracture of the fault, have inverse characteristics; those near the EW-trending secondary faults are links of the former faults, with a smaller length and normal faulting characteristics. Thus, the Zhangjiakou fault is a north-dipping inverse and partially south-dipping normal strike-slip fault. The Zhangjiakou fault has been continuously active since the Quaternary. With the exception of the western end extension, which has been active since the late Pleistocene, the main part of the fault has been active since the Holocene. The central main segment of the Zhangjiakou fault is more active. Since the mid-late period of the late Pleistocene, the average vertical slip rate of a single fault has been over 0. 07mm/a - 0. 30mm/a. The Zhangjiakou fault has multi-slip surfaces, and the total vertical slip rate reaches 1.33mm/a, estimated from the Qingshuihe river terraces and the relevant drilling data.展开更多
基金supported by the National Key Research and Development Project of China(No.2023YFC3007303)the Open Research Project of the Hubei Key Laboratory of Intelligent Geo-Information Processing(No.KLIGIP-2019B08)。
文摘0 INTRODUCTION.The global availability of digital elevation model(DEM)data,such as 90-m Shuttle Radar Topography Mission(SRTM)DEM and 30-m Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Model(ASTER GDEM),has been extensively utilized in morphotectonic analyses(e.g.,Wang et al.,2024;Cheng et al.,2018;Pérez-Pe?a et al.,2010;El Hamdouni et al.,2008).
基金central Yunnan Province(1:50,000)Chuxiong City,central Yunnan Province(Grant/Award Numbers:DD20220987)the National Natural Science Foundation of China(Grant/Award Numbers:41972118).
文摘The Longchuan River basin lies within the China Sichuan-Yunnan rhomboid block.The NS-trending Yuanmou-Lvzhi River Fault(YLF),NW-trending Chuxiong-Nanhua Fault(CNF)and Shiyang-Huoshaotun Fault(HSF)are found within the basin.The nature of the faults is complex,and the tectonic activity distribution characteristics require further clarification.By extraction from a digital elevation model,the measured longitudinal profile and the geomorphic indices of the Longchuan River,basin showed a stream-length gradient index(SL)of 49–650,hypsometric integral(HI)of 0.27–0.58,drainage basin asymmetry factor(AF)of 3.29–27.47,basin shape index(BS)of 0.87–2.75,valley floor width-to-height ratio(VF)of 0.06–5.40,and evaluation of relative tectonic activity(Iat)of 1.6–2.6.Results showed that river morphology and geomorphological indices in the Longchuan River basin were influenced by tectonic activity,bedrock lithology,climatic conditions,and development time,with tectonic activity playing a dominant role.The relative tectonic activity of the Longchuan River basin was zoned,with a gradual increase in relative tectonic activity from the south to the north.That the slip fault zone primarily controls the tectonic deformation of the Longchuan River basin in central Yunnan and the dynamics of the central Yunnan massif are consistent with the“rigid block lateral extrusion”1model.
文摘The West Anatolia Extensional Zone, which has a width of about 300 km, is located within the Alpine-Himalayan belt and is one of the regions with intense seismic activity in the world. The most important geomorphological structures in this area are three main graben structures resulting from regional N-S extension since the Early Miocene. These structures are the E-W trending Büyük Menderes, Kü?ük Menderes, and Gediz grabens. S?ke Basin is located at the SW end of the Büyük Menderes graben. The lineaments which control the NW of S?ke Basin have a length of approximately 40 km and have been defined as the Priene-Sazl? Fault(PSF). The PSF is seismically active, and the last large earthquake(the S?ke-Balat earthquake; Ms: 6.8) was produced on July 16 th of 1955. The ancient city of Priene, which was located in the study area, suffered from destructive earthquakes(in the 4 th century and 2 nd century BC, in the 2 nd century AD, during the Byzantine period and after the 12 th century BC). This study aims to reveal the effect of the PSF on the morphotectonic evolution of the region and the relative tectonic activity of the fault. To this end, it was the first time the stream length gradient index(SL: 130-1303), mountain-front sinuosity(Smf: 1.15-1.96), valley floor height and valley width ratio(Vf: 0.27-1.66), drainage basin asymmetry(AF: 0.15-0.76), hypsometric curve(HC) and hypsometric integral(HI: 0.22-0.86) and basin shape index(Bs: 1.04-5.75) along the mountain front that is formed by the PSF. Using a combination of the mountain-front sinuosity(Smf), valley floor height and valley width ratio(Vf), it is found that the uplift ratio in the region is not less than 0.05 mm/yr and the relative tectonic activity of PSF is high. According to the relative tectonic activity index(Iat) obtained from geomorphic indices, the southwest part of the PSF is relatively more active than the northeast part. As a result, I posit that the PSF has the potential to produce earthquakes in the future similarly to those that were produced in the past, and that the most destructive earthquakes will likely occur on the southwest segments of the fault according to geomorphic indices.
基金supported by the National Natural Science Foundation of China (Grant Nos.41430213 and 41304064)
文摘The eastern Tibetan plateau has been getting more and more attention because it combines active faults,uplifting, and large earthquakes together in a high-population region. Based on the previous researches, the most of Cenozoic tectonic activities were related to the regional structure of the local blocks within the crustal scale. Thus,a better understanding of the crustal structure of the regional tectonic blocks is an important topic for further study. In this paper, we combined the simple Bouguer gravity anomaly with the Moho depths from previous studies to investigate the crustal structure in this area. To highlight the crustal structures, the gravity anomaly caused by the Moho relief has been reduced by forward modeling calculations. A total horizontal derivative（THD） had been applied on the gravity residuals. The results indicated that the crustal gravity residual is compatible with the topography and the geological settings of the regional blocks,including the Sichuan basin, the Chuxiong basin, the Xiaojiang fault, and the Jinhe fault, as well as the Longmenshan fault zone. The THD emphasized the west margin of Yangtze block, i.e., the Longriba fault zone and the Xiaojiang fault cut through the Yangtze block. The checkboard pattern of the gravity residual in the SongpanGarze fold belt and Chuandian fragment shows that the crust is undergoing a southward and SE-directed extrusion,which is coincident with the flowing direction indicatedfrom the GPS measurements. By integrating the interpretations, the stepwise extensional mechanism of the eastern Tibetan plateau is supported by the southeastward crustal deformation, and the extrusion of Chuandian fragment is achieved by Xianshuihe fault.
基金the Research Council of Shiraz University which has supported the project
文摘This paper tests a data mining method for evaluation of the ＂IRTA＂（Index of Relative Tectonic Activity） to investigate the impact of active tectonics on geomorphic processes and landscape development. Based upon K-means clustering of six basin-related geomorphic indices（the hypsometric integral, basin asymmetric factor, drainage density, basin shape ratio, mean axial slope of the channel and topographic roughness） that represent the relative strength of active tectonic deformation on topography and morphology, the relative tectonic activity along the Kazerun Fault Zone in the Zagros Mountains of Iran may be classified into low, moderate and high relative tectonic activity zones. The results allow the identification of the clusters of similarly deformed areas related to relative tectonic activity. The utilization of geomorphic parameters as well as IRTA with comparison to the field observations exhibit change in relative tectonic activities mostly corresponding to the change in mechanism of the prominent fault zones in the study area.
文摘Decoupling between climate and tectonics, transform the elevation of earth surface regionally by denudation and displacement of land. To extract the tectonic footprints on morphology of landform, geormophometry is widely accepted tool due to visible responses in Drainage architecture to an intense tectonic environment. The present morphology of Yamuna basin in the Garhwal Himalaya, India is a result of continuing crustal deformation;erosion and deposition in the area. The drainage system and geomorphic expression of topography have been significantly influenced by active tectonics in this basin. In present study, for numerical modelling to detect the influence of tectonic signals on landform, we used morphotectonic parameters, to gradient index (SL), valley floor height to width ratio (Vf), asymmetry factor (Af), basin shape index (BS) and hypsometric integral (HI), extracted from SRTM DEM with resolution of 30 m. All these morphotectonic parameters are integrated to produce an index of relative active tectonics (IRAT). The Yamuna basin is classified into three groups based on IRAT, very high (<2.0);moderate (2.0 - 2.25) and low (>2.25) based on the degree of tectonic activity. Result shows approx. 56% of Yamuna basin experience high tectonic activity. This along strike deformation pattern pronouncedly emulates subsurface geometry based tectonic model.
基金funded by the Open Fund of Key Laboratory of Marine Geology and Environment,Chinese Academy of Sciences(Grant No.MGE2020KG10)the Open Fund of Key Laboratory of Submarine Geosciences,Ministry of Natural Resources(Grant No.KLSG 2208)+2 种基金the Natural Science Basic Research Program of Shaanxi(Grant No.2024JC-YBMS-227,2023-JC-QN-0287)the Postgraduate Innovation and Practice Ability Development Fund of Xi'an Shiyou University(No.YCS23113046)the National Natural Science Foundation of China(Grant No.41802128,42076219)。
文摘Tectonic activities significantly impact deep reservoir properties via sedimentary and diagenetic processes,and this is particularly true for lacustrine rift basins.The tectonic-sedimentary-diageneticreservoir system is crucial in deep reservoir exploration.This study examined the first member and upper submember of the second member of the Dongying Formation in the Bodong Low Uplift in the Bohai Bay Basin(East China),documenting the petrologic features and physical properties of reservoirs in different tectonic sub-units through integrated analysis of log and rock data,along with core observation.A mechanism for deep reservoir formation in lacustrine rift basins was developed to elucidate the sedimentary and diagenetic processes in complex tectonic settings.The results show that tectonic activities result in the occurrence of provenances in multiple directions and the existence of reservoirs at varying burial depths,as well as the significant diversity in sedimentary and diagenetic processes.The grain sizes of the sandstones,influenced by transport pathways rather than the topography of the sedimentary area,exhibit spatial complexity due to tectonic frameworks,which determine the initial pore content of reservoirs.However,the burial depth,influenced by subsequent tectonic subsidence,significantly impacts pore evolution during diagenesis.Based on the significant differences of reservoirs in slope zone,low uplift and depression zone,we establish different tectonic-diagenetic models in deep complex tectonic units of lacustrine rift basins.
基金supported by the National Natural Science Foundation of China(Nos.42172109,41872113,42172108)China National Petroleum Corporation-China University of Petroleum(Beijing)strategic cooperation science and technology project(ZLZX2020-02)+2 种基金Science Foundation of China University of Petroleum(Beijing)(Nos.2462020BJRC002,2462020YXZZ020)Natural Science Foundation of Chongqing(CSTB2022NSCQ-MSX1166)Science and Technology Research Program of Chongqing Municipal Education Commission(KJQN202201511).
文摘Previous studies have indicated that sediment gravity flow deposits developed in lacustrine active extensional rift basins are primarily influenced by tectonics and to a lesser extent by climate.Our present work reveals that climate can obscure the effect of tectonic subsidence by regulating sediment supply;conversely,tectonics can impede the sedimentary manifestation of climatic impacts.Here a case study has been presented to assess the impact of climate-modulated rapid lake-level rise and tectonic subsidence on the development of coarse-grained gravity flow deposits in the Dongying rift margin of the Bohai Bay Basin,eastern China.The lithofacies analysis reveals frequent bed amalgamation,abundant thick massive coarse-grained deposits,widespread cross bedding and plant fragments,and incomplete composite bed formed by high-energy erosion,indicating that the hyperpycnal flow is an important mechanism driving the deposition of these coarse-grained sediments.Detailed sequence stratigraphic analysis and sediment dispersal pattern suggest that the long-striped nearshore subaqueous fan systems induced by outburst-flood hyperpycnal flow distributed along the border fault,are primarily controlled by long-term tectonics,while the rapid rise of lake level driven by short-term climate change possibly intensifies seasonal flood-generated hyperpycnal flow occurrences and consequently promotes the basinal fan progradation.The maximum scale of these coarse-grained gravity flow deposits of the basinal fan systems are typically attained during the transgressive systems tract,which deviates from the classical sequence stratigraphic model.Furthermore,it presented a continuous transition from the proximal to the distal part,encompassing traction flows and turbidity currents during the periods of relatively stable tectonics.Nevertheless,gravel-rich debris flows appear to predominate the dispersion of coarse-grained sediments during periods characterized by intense tectonic activity.The coarse-grained gravity flow deposits in the lacustrine rift margin reported here,challenge the traditional beliefs:this study suggests that subaqueous deposits abundantly preserved in the transgressive setting.
文摘Understanding the active tectonic processes in the Nandakini Watershed is imperative for evaluating geological hazards and seismic risks,as well as for informing land-use planning and natural resource management strategies in the region.Tectonic geomorphology serves as a vital tool for characterizing recent tectonic movements.This research employs GIS techniques to elucidate tectonic activity and its influence on drainage patterns in the Nandakini Watershed,utilizing morphometric parameters derived from SRTM DEM data.Morphometric indices are employed to assess the tectonic movement within drainage basins,capturing both areal and linear factors such as drainage density,texture,circulatory and bifurcation ratios,and stream length ratios.The linear and areal morphometric indices are categorized into three classes representing varying degrees of active tectonic activity.These classifications are then utilized to compute the relative active tectonic index(IRAT).In addition,geomorphic parameters include hypsometric integral,stream length-gradient index,normalized steepness index,chi gradient index,and swath profiles.The majority of the studied region is in an extremely high to moderately active tectonic zone.Large-scale faults and thrusts within the basins are closely correlated with these zones that have been identified.The integrated methodology of GIS-based morphometric analysis and geomorphic study enables the identification of deformed landforms associated with ongoing tectonic activity.Furthermore,these results offer valuable insights for informing watershed management strategies and promoting sustainable land use planning initiatives.
文摘This research investigates dynamic earth processes within the South Setifian allochthonous ensemble,providing insights into landscape evolution and seismotectonic activity within the Tellian mountain chain.Focusing on the Jebel Gustar and Kef Lahmar area,which includes 14 sub-basins,this research uses a DEM-based technique to assess Holocene activities,lineament characteristics,and stream systems.Five geomorphic indices are used to assess relative active tectonics:the stream lengthgradient index(SL),drainage basin asymmetry(AF),valley-floor width to valley height ratio(VF),drainage basin shape(BS),and mountain front sinuosity(SMF).A weighted overlay of these five indices produces the Index of Relative Active Tectonics(IRAT)map.The findings reveal significant neotectonic activity in the study area,supported by profound basement faulting.This research highlights the morpho-structural processes and neotectonics activity in the Jebel Gustar,providing a framework for investigating the evolution of this structure.Additionally,it enhances comprehension of the interactions between the alpine range's internal zones in Eastern Algeria and the Atlasic domain.This study proposes a systematic approach to evaluate the tectonic and geomorphological dynamics of the South Setif region.
基金supported by National Natural Science Foundation of China (Grant No. 40902095)Basic Research Funds from the Institute of Geology, China Earthquake Administration (Grant No. DF-IGCEA-0608-2-6)the State Key Laboratory of Earthquake Dynamics (Project No. LED2009A07)
文摘The use of satellite thermal infrared information is being developed as a method of exploring current tectonic activity. To realize real world application, an objective, stable and testable thermal physical index that is simultaneously related with tectonic activity must be established. From the viewpoint of the energy balance, the land surface is a boundary where energy is exchanged between outer space and the solid Earth. Regardless of how complex the influencing factors are, the land surface is mainly affected by the Sun, atmosphere and underground heat. In this paper, first, the relationships among land surface temperature, solar radiation, atmospheric temperature and thermal information from underground are obtained employing a mathematic physical method based on the equation of heat conduction and energy balance at the land surface. Second, a thermal physical index called the geothermal flux index (GFI), which can provide the activity state of underground heat, is constructed. Third, the theoretical basis of the thermal physical index is verified using stable annual variations in land surface temperature and solar radiation. Finally, combined with known crustal deformations derived using a global positioning system, the effectiveness of the GFI in extracting field tectonic motion is tested. The results indicate that the GFI is effective in providing information on current tectonic activity.
基金supported by the Key Research and Development Plan of Yunnan Province:The Technology of the Comprehensive Risk Assessment of the Earthquake Catastrophe and the Disaster Chains in Yunnan and Its Application(No.202203AC100003)Institute of Geology,China Earthquake Administration(No.IGCEA2302)。
文摘Quantitative geomorphic analyses are usually powerful in identifying active tectonics across global orogenic belts.Our present study will focus on the Anatolian Plate which hosts a lot of recent catastrophic earthquakes in Türkiye.Six geomorphic indices for 100 sub-basins around Türkiye have been computed including local relief,slope,normalized steepness index(k_(Sn)),hypsometric curve and integral(HI),transverse topographic symmetry factor(Tf),and the basin asymmetry factor(Af).The averaged kSnand Af values have shown four high-value anomalous zones,suggesting relatively high uplift rates featured by high river incision and regional tilting.The values of 0.35≤HI<0.6 for basins with S-shaped curves imply intensive tectonic activities along the eastern part of the North Anatolian Fault Zone(NAFZ),the Northeast Anatolian Fault Zone(NEAFZ),the East Anatolian Fault Zone(EAFZ),and the Central Anatolian Fault Zone(CAFZ).All results of the geomorphic indices analysis suggest a relatively high degree of tectonic activity in the following four areas,the Isparta Angle,the Eastern Black Sea Mountains,the South-eastern Anatolia Region,and the Central Anatolian fault zone.We further suggest that the eastern part of the NAFZ,NEAFZ,EAFZ,and CAFZ will be more active in tectonic activities,with a greater potential for strong earthquake occurrence.
基金The work was supported bythe public welfare programofthe Ministry of Science and Technology of China (2004DIA3J010)the special preparatoryresearch of national keyfun-damental research project (2002CCD01700)the Young Scientists Funds of Institute of Earthquake Science , CEA(QN200401) .
文摘Based on the research and the division of the active tectonic blocks and their boundaries on the Chinese mainland, the feature of the large earthquake activities on the 24 boundaries between the 6 active tectonic block regions (grade Ⅰ) and the 22 active tectonic blocks (grade Ⅱ) are studied. The seismicity levels on the active tectonic block boundaries are discussed considering the large earthquake frequency and the released strain energy in unit distance and time. The theoretic maximal magnitude and the recurrence period of each boundary are then calculated from the G-R relation. By comparing this with the actual earthquake records, it is found that the intensities of the earthquake deduced from the seismic activity parameter (a/b) on the main active boundaries on the Chinese mainland are consistent with that of the natural earthquakes. Meanwhile, an inverse relation is found between the recurrence periods of large earthquakes and the tectonic motion rate on the boundaries. These results show that the a, b values of each boundary obtained in this paper are valuable. In addition, the present seismic activities and hazards of these boundaries are also probed into with the historical data and their elapsed time on each boundary based on the hypothesis that the large earthquakes satisfy Poisson distribution.
文摘Based on the hypothesis of the active tectonic blocks on the Chinese continent and its adjacent regions (both the method of the DDA on a spherical surface and the GPS survey results observed from 1991 to 2001 are used), the movements and deformations of each active tectonic block are calculated. The calculation results show that although the movements and deformations of active tectonic blocks in the eastern region and in the western region of China are different, active tectonic blocks in the same active tectonic block region are coherent. Then, the relative velocities of the active tectonic blocks’ boundary zones are calculated, and the relationship between current crustal motion and strong seismic activities is discussed. Earthquakes ( M S≥7 0) on the Chinese continent since 1988 all occurred on boundary zones of active tectonic blocks with high slipping speed.
基金Research Development Fund(IIT Bombay)supported SM。
文摘Active tectonics in an area includes ongoing or recent geologic events.This paper investigates the tectonic influence on the subsidence,uplift and tilt of western Saurashtra through morphotectonic analysis of ten watersheds along with characteristics of relief and drainage orientation.Watersheds 7-9 to the north(N)are tectonically active,which can be linked with the North Kathiawar Fault System(NKFS)and followed by watersheds 6,10,1,4 and 5.Stream-length gradient index and sinuosity index indicate the effect of tectonic events along the master streams in watersheds 6-9.Higher R^(2)values of the linear curve fit for watershed 7 indicate its master stream is much more tectonically active than the others.The R^(2)curve fitting model and earthquake magnitude/depth analysis confirm the region to be active.The reactivation of the NKFS most likely led to the vertical movement of western Saurashtra.
文摘The Okinawa Trough is a very active tectonic zone at the margin of the Northwest Pacific and is typical of back arc rifting at the young stage of tectonic evolution. Many scientists from Japan, China, Germany, France, the U.S.A. and Russia have done a lot of geologic and geophysical investigations there. It is well known that the Okinawa Trough is an active back arc rift with extremely high heat flow, very strong hydrothermal circulation, strong volcanic and magmatic activity, frequent earthquakes, rapid subsidence and rifting, well developed fault and central graben. But up to now, there are still some important tectonic problems about the Okinawa Trough that require clarification on some aspects such as the type of its crust, its forming time, its tectonic evolution, the distribution of its central grabens, the relationship between its high heat flow and tectonic activity. Based on the data obtained from seismic survey, geomagnetic and gravity measurements, submarine sampling and heat flow measurements in the last 15 years, the author discusses the following tectonic problems about the Okinawa Trough: (1) If the Okinawa Trough develops oceanic crust or not. (2) Is the South Okinawa Trough tectonically more active than the North Okinawa Trough with shallower water and few investigation data on it. (3) The formation time of the Okinawa Trough and its tectonic evolution. The Okinawa Trough has a very thin continental crust. Up to now, there is no evidence of oceanic crust in the Okinawa Trough. The North, Middle and South Okinawa Trough are all very strongly active areas. From 6 Ma B.P., the Okinawa Trough began to form. Since 2 Ma, the Okinawa Trough has been very active.
文摘The Colca Valley in the Central Andes is a region characterized by the occurrence of large slow-moving landslides and a high level of seismic activity.In this study,we aimed to determine passive and active tectonic control on the formation of selected five large landslides in the Colca Valley and to assess geohazard associated with these features.For that purpose,we performed a post-landslide field survey,applied remote sensing techniques,and obtained eyewitness accounts.Recently,the need to understand mass movement processes in this region is even higher due to the establishment of the Colca y Volcanes de Andagua Geopark(Colca and Andagua Volcanoes Geopark).Our results suggest that the studied landslides usually represent a complex failure mechanism,dominated by translational sliding or rotational displacements,commonly associated with the formation of horst-and-graben like structures.We found a spatial correlation between the distribution of landslides and inherited fault network.The head scarps appear to be limited by the WNW-to NW-striking faults,whereas the lateral extent of some of the reported features seems to be connected with the NNE-striking normal faults,common in both,the Mesozoic strata and the Pleistocene-Holocene deposits.
基金Supported by Knowledge Innovation Program of the Chinese Academy of Sciences (KZCX-SW-234) and Key Laboratory Program of CAS (MSGL0609).
文摘Analysis on helium isotopes in natural gas in Bohai Bay Basin showed their mantle-origin indicated by high 3He/4He ratio. The span of 3He/4He ratio increased from west to east. This pattern im- plied a close relationship to the local tectonic setting. Bohai Bay Basin experienced intensive neo-tectonic activities in the Cenozoic. Widespread faulted-depressions and strong volcanic eruptions manifested its extensional tectonics. Abiogenic natural gas could be released from magmas and migrate upward through deep faults during the extension. Tectonic conditions in the area would favor upward invasion and reser- vation of mantle-originated helium. Furthermore, with decrease of convergence rate between the Pacific and the Eurasia Plate, the subduction slab of the Pacific Plate rolled back and became steeper, resulting in mantle flow and other tectonic activities migrating from west to east in nature, and caused the variation in isotopic helium ratios.
基金sponsored by the Active Fault Exploration and Earthquake Risk Evaluation Program of City (Grant No. 684[2007],Hebei Provence,China)the Special Earthquake Scientific Research Program,China
文摘Based on detailed field investigations, this paper describes the geometrical characteristics and tectonic activities of the Zhangjiakou fault at the northwest of Beijing. This fault strikes mainly northwest to west, short parts of which strike near east to west, dipping north, and extends over a length of 70km. It is a major geological and geomorphologicai margin, controlling the neotectonic movement in this region. On the south side of the Zhangjiakou fault are the Late Quaternary unconsolidated deposits, forming basins; while on the other side are Mesozoic volcano debris and Pre-Mesozoic metamorphic rocks, forming lower mountains and hills. The Zhangjiakou fault consists mainly of high-angle inverse strike-slip fault and partially of normal strike-slip fault. Among these, the north-dipping NW-NWW-trending secondary faults, constituting the main fracture of the fault, have inverse characteristics; those near the EW-trending secondary faults are links of the former faults, with a smaller length and normal faulting characteristics. Thus, the Zhangjiakou fault is a north-dipping inverse and partially south-dipping normal strike-slip fault. The Zhangjiakou fault has been continuously active since the Quaternary. With the exception of the western end extension, which has been active since the late Pleistocene, the main part of the fault has been active since the Holocene. The central main segment of the Zhangjiakou fault is more active. Since the mid-late period of the late Pleistocene, the average vertical slip rate of a single fault has been over 0. 07mm/a - 0. 30mm/a. The Zhangjiakou fault has multi-slip surfaces, and the total vertical slip rate reaches 1.33mm/a, estimated from the Qingshuihe river terraces and the relevant drilling data.
