Tectonic Faults Research Articles

Crustal electrical structure and seismicity of the Weiyuan shale gas block in Sichuan Basin, southwest China

Abstract Hydraulic fracturing, a significant contributor to seismic activity within and around operational fields, has been extensively used in shale gas production. Magnetotelluric (MT) sounding is an effective geophysical tool for identifying high-conductivity fluid-filled and/or molten regions. In this study, we deploy a dense grid of rectangular MT sites to investigate the 3D geoelectrical resistivity structure beneath the Weiyuan shale gas block (WSGB) and subsequently examine the causes of seismic activity. The resistivity data, obtained through 3D inversion accounting for topography using ModEM, reveals a shallow low-resistivity layer (<10 Ω-m) within the WSGB, ranging from ∼2 to 5 km in depth. This layer exhibits multiple isolated areas with very low resistivity (<5 Ω-m), indicative of fluid-filled zones associated with hydraulic fracturing or shale gas-bearing formations. In the northwestern WSGB, the Weiyuan anticline presents a high-resistivity dome extending possibly to depths beyond 20 km, without extending beyond the northern boundary of our study area. Conversely, the sedimentary zone in the southeastern WSGB displays a low-resistivity feature, with an extremely low-resistivity center (<1 Ω-m). Since a consistent high-resistivity zone exists beneath each fault and its top depth is <5 km, so faults might not extend downward below 5 km. Earthquakes with magnitudes (ML) of 3.0 or higher predominantly occur close to the faults, when considering industrial production data, we found a noteworthy correlation between earthquakes with ML < 3.0 and annual shale gas production within the WSGB. Tectonic faulting is not the leading cause for ML < 3.0 earthquakes but likely the primary contributor to seismic events with ML ≥ 3.0.

Detecting hydrodynamic barriers of reservoirs based on drilling of horizontal wells to refine geological models

During the geological modeling process, it can be problematic to substantiate predicted faults or barriers that are estimated from seismic data and require additional research. However, logging data from horizontal wells (LWD — logging while drilling), whose trajectories intersect predicted seismic faults or hydrodynamic barriers, can be used to validate such barriers.The aim of this study is to substantiate hydrodynamic barriers in several fields in Western Siberia using data from a complex of geophysical surveys conducted while drilling horizontal wells that pass through such barriers. The main research method is azimuthal gamma-gamma density logging and its interpretation to identify hydrodynamic barriers, including tectonic faults, based on the criteria described in A. V. Chashkov's, S. Z. Mutaev's and other scholars' works.This study presents the practical application of the azimuthal gamma-gamma density logging method to substantiate predicted seismic faults, estimated from seismic data and require additional research, using the example of the First field. This model has been examined and accepted by the State Reserves Committee.

Анализ напряженно-деформированного состояния моделей разрывных нарушений

The paper analyzes the procedure of creating three-dimensional models of discontinuous and tectonic faults for numerical modeling problems using the finite element method. A number of uncertainties arise in the geomechanical analysis of the stress-strain state of faults due to the choice of the type of their computational geological model, e.g. the dislocation, domain or dynamic impact zone models. A comparative analysis of the stress-strain state in the mentioned computational geological models is performed. The geological and structural models are based on the geological sampling data collected in the investigated area. Special attention is paid to building the structural-tectonic model with account of discontinuous and tectonic faults that affect the deformations and stresses of the rock mass. As the result, the most preferable of the three given options is the computational geological model with the dynamic impact zone. The domain of the dynamic impact zone with lower physical and mechanical properties makes it possible to cover the entire potential volume of the rupture zone.

Geological Aspects of the Formation and Distribution of Gas Anomalies in Bottom Sediments of the New Siberian Sedimentary Basin and Adjacent Geostructures of the East Siberian Sea

Abstract —In bottom sediments of the New Siberian sedimentary basin and adjacent geostructures of the East Siberian Sea, we identified СН4, as well as its limit and unsaturated homologues (up to and including C5H12), CO2, CO, H2, He, H2S, O2, N2, and Ar. Isotope-gas-geochemical parameters δ13С СО2, СН4 and С2Н6, of the molecular mass of hydrocarbon fraction and genetic coefficients indicate the presence of both syngenetic and epigenetic gases of various gas sources in sediments, including recent sediments, peatlands, coal-bearing and gas-bearing formations, solid bitumen, igneous formations, accumulations of gas hydrates and prognostic condensate-gas, condensate, oil-and-gas and gas-and-oil reservoirs. Concentrations of CO2 and CO reach 29.25 and 0.06 cm3/kg, CH4 and the sum of its homologues – 5.93 and 0.031, Н2 and He – 0.78 and 0.318, H2S – 0.092 cm3/kg; this indicates that gas-geochemical anomalies, exceeding the anomaly criteria by 6–124 times, form in bottom sediments. The formation and distribution of abnormal concentrations of natural gases depend on the complex influence of gas-controlling factors – geological structure, fold and fault tectonics, magmatism, coal-oil-gas content, bituminous content, organic saturation, lithological composition, water-physical and reservoir properties of sediments, hydrogeological, geocryological and other conditions for accumulation of natural gases or their degassing.

Timing of India-Asia collision and significant coupling between them around 51 Ma: Insights from the activation history of the Zhongba-Gyangze thrust in southern Tibet

Abstract Constraining the timing of tectonic coupling between converging plates is crucial for understanding the transition from continental subduction to continental collision. In the case of the India-Asia collision, thrusting of an accretionary complex onto the Indian continental margin provides the most direct temporal constraint on the early stages of continental collision, as it represents the most immediate upper-crustal fault system corresponding to plate coupling. Here, we used structural analysis combined with K-Ar dating and hydrogen isotopes of authigenic illite and muscovite to unravel the time-progressive development of the Zhongba-Gyangze thrust (ZGT), which represents a tectonic boundary fault in southern Tibet. Our results suggest that the ZGT evolved from its initiation as a single fault zone infiltrated by metamorphic fluids with high δD values (–47‰ to –55‰) at ca. 80 Ma to multiple deformation localization zones starting around 51 Ma. This latter phase is represented by the development of different generations of authigenic 1 M/1Md illite and significant input of meteoric fluids with δD values ranging from –71‰ to –98‰ through multiple episodes of brittle fault reactivation. A Late Cretaceous tectono-thermal event related to the subduction of a Neotethyan oceanic ridge may have been responsible for the formation of 2M1 illite/muscovite at ca. 80 Ma. The oldest (ca. 51 Ma) 1 M/1Md illite age coincides with the first major pulse of shortening in the upper plate after the initial India-Asia contact. Given the synchronous deceleration of India-Asia convergence, the ca. 51 Ma deformation pulse across the Yarlung-Zangbo suture zone demarcates strong coupling (i.e., the onset of continental collision) between India and Asia at this time.

On the nature of the Talysh-Vandam Mesozoic uplift and the West Caspian tectonic fault (in the order of discussion)

On the basis of seismostratigraphic studies, the nature of the Talysh-Vendam gravity maximum and the West Caspian deep fault has been revised, and a number of interesting results have been obtained. Thus, in the interval from the end of the Cretaceous to the end of the Sabunchu Formation of the Lower Pliocene, a sharp discrepancy between the geological sections of the basins of the Lower and Middle Kura, when (from the end of the Miocene) the level of erosion of the former decreased to 1800 m, in the latter remained above sea level until the end of the Surakhan (lower Pliocene) formations. Based on the results of seismostratigraphic studies, it was proposed to use the term Mingachevir-Saatly-Talysh Mesozoic uplift zone as tectonic elements instead of the Talysh-Vendam gravity maximum, Kurdamir-Saatly and Mingachevir-Goychay Mesozoic uplifts. Although in the basin of the Lower Kura there was a deepening up to 1800 m, corresponding in age to the Messinian eustatic drop in sea level, the subsidence of the bottom of a basin of this magnitude was associated with bending processes. The results of seismostratigraphic studies state that the Mingachevir-Saatly-Talysh zone of the Mesozoic uplift divides the Kura sedimentary basin into two blocks, such as the Lower and Middle Kura depressions, and not the West Caspian deep fault. The results of seismic studies on a regional scale once again confirmed that the West Caspian Fault does not occur in the geological section of the territory of Azerbaijan, at least in its Cenozoic interval.

High time-resolved studies of stick-slip show similar dilatancy to fast and slow earthquakes.

Fast and slow earthquakes are two modes of energy release by the slip in tectonic fault rupture. Although fast and slow slips were observed in the laboratory stick-slip experiments, due to the sampling rate limitation, the details of the fault thickness variation were poorly understood. Especially, why a single fault would show different modes of slip remains elusive. Herein, we report on ring shear experiments with an ultrahigh sampling rate (10 MHz) that illuminate the different physical processes between fast and slow slip events. We show that the duration of slips ranged from dozens to hundreds of milliseconds. Fast slip events are characterized by continuous large-amplitude AE (acoustic emission) and somewhat intricate variation of the sample thickness: A short compaction pulse during the rapid release of stress is followed by dilation and vibrations of the sample thickness. As the slip ends, the thickness of the sample first recovers by slow compaction and then dilates again before nucleation of the following slip event. In contrast, during slow slip events, the shear stress reduction is accompanied by intermittent bursts of low-amplitude AE and sample dilation. We observed the detailed thickness variation during slips and found that dilation occurs during both fast and slow slips, which is consistent with natural observations of coseismic dilatation. This study may be used to reveal the mechanism of fault slips during fast and slow earthquakes, which explain the potential effect of fast and slow slips on stress redistribution and structural rearrangement in faults.

ON RADON ACTIVITY OF TECTONIC FAULTS IN THE AREA OF SITING THE SINOP NPP IN THE REPUBLIC OF TŰRKIYE

Problem statement. The paper provides an additional expanded justification for applying an innovative methodology in the area of the future Sinop NPP, planned to be deployed in the Republic of Tűrkiye, to identify the activity rate of tectonic faults in soil foundation based on comprehensive radon measurements using the PSACEA universal estimation scale. The purpose of the article. Current radon activity assessment of existing tectonic faults in Earth’s crust based on archival measurements of soil radon carried out earlier in Sinop Province. Conclusions and results. Current analysis of radon measurement results obtained previously by the track method made it possible to further assess the radon activity rate of tectonic faults existing in the area of the future nuclear power plant. The proposed methodology to assess radon activity of tectonic faults in Earth’s crust involves increasing safety during the construction and operation of the future nuclear power plant. The regulation on using this methodology as part of the subsurface monitoring at the Sinop NPP can be enshrined in job descriptions. This methodology can also be used as part of the seismic monitoring of other sites at the nuclear power plant, especially those located in high seismic risk zones.

Study of the Migrating Mine Gas Piston Effect during Reactivation of Tectonic Faults

The hypothesis of the piston effect during mine gas migration caused by fault reactivation was studied, with the use of computer modeling, to explain cases of a sudden appearance of mine gases on the earth surface in coal mining areas. The study is based on the factual data of the mode and amplitudes of subsidence along faults during mining, the morphology of the fault planes, and the theoretical ideas about the discrete nature of the fault wall displacement along uneven contact surfaces. It is taken into account that the walls of the fault, due to the asperity types “ridge” and “sag”, form contacts of the “ridge–ridge” and “ridge–sag” patterns. This study examines the situation where gas pressure in the fracture space can sharply increase due to the jerky displacement of reactivated tectonic fault walls with a rough fault plane. It is assumed that, in the first phase of reactivation, the fracture space expands as a result of the displacer opening and the fact that fault plane asperities engage in the “ridge–ridge” type of contact. With the subsequent relative displacement of the fault walls in the second phase of reactivation, the contact changes into the “ridge–sag” type and a sharp reduction in the fracture space volume occurs. It is shown that a “piston effect” emerges due to the reduction in fracture space and that it promotes an increase in gas pressure and stimulates gas movement to the surface through the available channels. The resulting “piston effects” may also be responsible for the suddenly raised gas content recorded in the air of surface structures and recurrent mine gas migration onto the surface. The findings expand our understanding of the sudden gasification of the earth surface and living spaces in coal mining areas and contribute to the understanding of the gas migration process, thereby helping to monitor hazards.

Geothermal field model in the southeast of Shijiazhuang Region (China) deduced from magnetotelluric data

Shijiazhuang is located in the contact area between the Taihang Mountain Uplift and the Jizhong Depression of the North China Plain, adjacent to the eastern Taihang Mountain Fault. The major geothermal fields are located to the southeast of the Shijiazhuang region. Considering that the origin of these geothermal fields can be better delineated via geophysical methods, in this study, broadband magnetotelluric data were acquired from 51 stations. The aim of this study was to understand the underlying mechanism of the action of a geothermal system in terms of resistivity and other known information. Before inversion, the data were processed via remote reference technique, and the dimensionality and geoelectric strike directions were analyzed. 2D inversion of the TM-mode data was performed via the non-linear conjugate gradient method, and a deep electrical structure was imaged. Combining the data with previous data, the tectonic units and fault distribution of study area were comprehensively interpreted. The four components of the geothermal system have been identified: a heat source, channel, thermal reservoir, and caprock. The low-resistivity layer in the middle crust was considered as a deep heat source, and the fault was a heat diffusion channel. The high-porosity carbonate rock in the uplift area was considered as a thermal reservoir, and the overlying Neogene and Quaternary strata were considered as caprocks for thermal insulation. This study provides valuable reference basis for studying geothermal fields in this area.

Contribution of Aeromagnetic Data to the Structural Discontinuities Identification of Black Volta Catchment Aquifer System in Côte d'Ivoire

This paper focuses on improving the structural knowledge of the fissured aquifers of the Black Volta catchment in Côte d'Ivoire based on the mapping of magnetic lineaments, which represent magnetic discontinuities such as magmatic body contacts or tectonic faults. Four filtering methods, pole reduction (equator), gradient (vertical and hori-zontal), upward extension, and angle tilt, were applied to the residual magnetic field map to extract magnetic discontinuities while using the Oasis Montaj (Geosoft) program. Euler deconvolution coupled with the analytical signal provided, in addition to the horizontal location of the magnetic contacts, is an indication of their depths. The resulting structural map contains 458 structures, with lengths ranging from 9.03 to 66.54 km. Three directions, NW-SE, E-W and NE-SW, were detected with a predominance of the NW-SE direction. Depths estimated by Euler solutions range from 6.8 to 2847 m. This map is consistent with many faults already recognised or assumed by traditional structural studies and tectonic events affecting the Ivorian basement. These results contribute significantly to the improvement of the structural map of the Black Volta Basin in Côte d'Ivoire. In addition to the major known tectonic faults, numerous lineaments, particularly those at depth, have been highlighted by the present study.

Evaluation of landslides, accretion circumstance and riverbank slope stability analyses in the Mekong Delta

This study presents the current situation of landslides and accretion on the Tien and Hau riverbanks in the Mekong Delta over time. Simultaneously, the riverbank slope stability was assessed and showed some related effects. Statistical methods, combined with field surveys and GEOSlope analysis, were used to assess the circumstances of landslides and accretion. Results show that the most landslides have occurred in the An Giang and Dong Thap areas. In the prior 2015 period, 23 and 7 riverbank sections with frequent landslides were excavated and inventoried on the Tien and Hau rivers, respectively. Meanwhile, 28 and 9 sections where accretion occurred during this period were inventoried on the Tien and Hau riverbanks, respectively. Since 2015, 248 locations of landslides and accretion occurring in the area have been investigated. The study also indicates that the displacement of active tectonic faults and instability of riverbank slopes have been demonstrated and complemented the landslide causes in the area. These results are intended to warn and help local authorities to promptly take positive measures to prevent and orient appropriate socio-economic development for the region.

PERANCANGAN PICTURE STORYBOOK BERBASIS AUGMENTED REALITY (AR) TENTANG EDUKASI SIGAP BENCANA ALAM UNTUK ANAK USIA 9-12 TAHUN

Indonesia is a country that is prone to natural disasters because it is located on a tectonic plate fault in a row of active volcanoes in many areas, making Indonesia at risk of natural disasters such as volcanoes, earthquakes, and further disasters such as floods. Mini-type disasters certainly have an impact on society, especially children. Therefore education is needed regarding alertness to natural disasters. Using qualitative and quantitative research methodologies, namely data collection through questionnaires to 150 respondents, interviews with expert sources, as well as literature studies, existing studies, and comparative studies. The design of this augmented reality-based picture story book uses a style adapted to children, starting with the formulation of keyword concepts, verbal concepts, to visual concepts including titles, synopsis, language style, image styles, colors, typography, character designs, cover designs, to the contents of the page that produced a picturebook with augmented reality entitled “Zalfa the Nature Explorer”. This design has the aim of educating children aged 9-12 years with creative and innovative methods, through this design it is hoped that children will be more aware and alert when facing natural disasters so that they can reduce victims of natural disasters that occurred in Indonesia.
 Keywords: picture storybook, augmented reality, alert for natural disasters, education, children

Preliminary Survey of Exposure to Indoor Radon in al-Farabi Kazakh National University, Kazakhstan

Radon is a major source of naturally occurring radioactivity, and its measurement is considered extremely important in radiation protection, given its association with lung cancer. This pilot study aimed to estimate the annual effective dose received by students and staff based on monitoring data on the concentration of radon in the buildings of al-Farabi Kazakh National University (Almaty, Republic of Kazakhstan), based on the distance to the tectonic fault. The measurements were recorded daily from February 2021 to September 2022 using a RAMON-02 radiometer (SOLO LLP, Almaty, Kazakhstan). All measurements were taken from the basement to the top floor under normal conditions of use. The average accumulated concentrations of radon in the studied buildings ranged from 16.34 to 78.33 Bq/m3, which is below the maximum level of 100 Bq/m3 established by the World Health Organization (WHO) and the legislation of the Republic of Kazakhstan (200 Bq/m3). Relatively high values were recorded in the basement of the Faculty of Physics and Technology building (282.0 Bq/m3 in winter, 1742.0 Bq/m3 in spring, 547.7 Bq/m3 in summer, and 550.7 Bq/m3 in autumn), which is located closest to the tectonic fault and poorly ventilated. In almost all rooms (94%), radon levels were within the WHO-recommended reference level. The averaged results show the influence of the distance to the fault on the average indoor radon levels. The annual effective dose of radon for university students and staff ranged from 1.09 mSv/year to 1.53 mSv/year. The excess lifetime risk of developing cancer ranged from 0.44% to 0.61%.

Magnetic field map of the Wilhelm Archipelago shelf zone, West Antarctica

The Antarctic Digital Magnetic Anomaly Project is an international research effort to construct a magnetic map of the continent based on ground, satellite, marine, and aeromagnetic surveys. This paper reports the magnetic mapping of the shelf zone in the SE part of the Wilhelm Archipelago, West Antarctica, based on magnetic surveys conducted with Zodiac boats. A spectacular feature of this area is the strong magnetic anomaly of the Antarctic Peninsula (AP) batholith, which was the product of subduction-related Mesozoic–Cenozoic arc magmatism on the former margin of Western Gondwana. We constructed and analyzed a detailed magnetic map of magnetic field anomalies using field observations of rock exposures on the islands and magnetic properties of rocks from laboratory data. The oldest volcanic rocks of Jurassic to Lower Cretaceous age relate to N-NE trending bands of negative magnetic field. The largest feature in the study area is an Upper Cretaceous/Paleogene granodiorite complex that produces a positive magnetic anomaly. Many smaller anomalies are also present over gabbroid bodies of Cretaceous age. Two-dimensional magnetic modeling shows that heterogeneities in the upper crust may have magnetic susceptibilities in the range of 0.005–0.13 SI. Magnetic field anomalies also delineate an orthogonal system of tectonic faults, including the main NE fault along the Penola Strait (sub-parallel to the AP coastline) and four intersecting faults. These fault systems may be associated with different stages of continental margin evolution along the Antarctic Peninsula.

Landscape evolution modeling of the normal-fault scarps (Baikal rift system): new experience

The paper considers a new method for determining the quantitative parameters of the relief-forming processes characteristic of the mountainous framing of the basins of the Baikal Rift System (BRS), based on the use of a computer program for numerical simulation of the evolution of the relief CHILD. Particular emphasis was placed on the calculation of approximate values of the rate of tectonic uplift of the near-fault block structures of the Baikal rift. The novelty of the study lies in the adaptation of the CHILD program for solving fault tectonics problems, as well as in the development of a morphotectonic analysis algorithm aimed at searching for specific geomorphological objects that can be considered as uplift indicators. As a result of a series of experiments performed using radioisotope data, three-dimensional models were obtained that simulate the development of near-fault slopes at the Late Cenozoic stage of the development of the BRS, and the probable rates of vertical movements along the faults of the region were determined. It was found that the average Late Cenozoic uplift rates vary within a narrow range of 0,3–0,5 mm/yr, with higher values associated with the northern and northwestern flanks.

Effect of Traveling Waves on Seismic Behavior of Fault-Crossing Transmission Tower-Line Systems

Ultra high voltage (UHV) transmission tower-lines systems (TTLSs) are responsible for the crucial function of transmitting and distributing electrical power over long distances, which inevitably traverse active tectonic faults when passing through seismic areas. This paper investigates the seismic behaviors of the fault-crossing UHV TTLSs, taking into account the traveling wave effects of fault-crossing ground motions. Furthermore, three scenarios (i.e. the fault located at the midspan, the side span, and the one side) according to the location of the faults relative to the TTLSs, are designated to investigate the effects of fault-crossing locations on the seismic behaviors of the fault-crossing TTLSs. The results indicate that the traveling wave effects may amplify or weaken the seismic responses and collapse of the near-fault and fault-crossing TTLSs, and the effects on the longitudinal displacement responses of the TTLS are significantly greater than those in the transverse direction, but they do not affect the distribution of the collapse weak position of the TTLSs across the fault. Besides, the effect of traveling waves on the seismic behaviors of the transmission tower further away from the fault is greater than that relatively closer to the fault. This study of the impact of the traveling wave effects and fault-crossing locations on the TTLSs serves as a valuable reference for seismic behaviors of the UHV TTLSs crossing faults.

Evaluation of Displacements Caused by Strike-Slip Deformations Using Correlation Characteristics Based on Potential Field Data

The identification of faults is a common objective in geophysical potential field methods. Vertical discontinuities such as reverse faults, also known as tectonic faults, can easily be distinguished through their effect on gravity and magnetic fields, appearing as gradient zones or areas of change in the field. However, identifying strike-slip faults is one of the biggest challenges for potential field methods as they are characterized by a complex series of anomalies with varying signs in the fault zone, as well as displacement of anomaly axes between the strike-slipped blocks. The goal of this study is to suggest a transformation that would aid in the identification of shear zones through the calculation of the displacement along the discontinuity. The proposed approach involves calculating the correlation coefficient between parallel profiles using moving windows. The position of the window with the highest calculated correlation coefficient allows estimating of the discontinuity displacement magnitude. The method was tested using a synthetic field and data from the magnetic field of the Kolbeinsi Ridge.

Analysis of structural-tectonic and petrophysical features of productive horizons of Mishovdag fold


 
 
 The article analyzes the geological structure, lithofascial, tectonic, and morpho- logical features of the Mishovdag oil field, which is a productive area in terms of oil content. Morphologically, it represents a brachianticlinal fold located in the north-west and south-east directions. The Mishovdag fold is located on the Kalamaddin-Bandovan anticline zone between the Kichik Harami (in the northeast) and Galmaz (in the northwest) structures. The Mishovdag-Galmaz part of the anticlinal zone extends in the sub-southern direction. The structures included in the zone are represented on the surface mainly by Aghjagil, Absheron, and ancient Khazar sediments. Productive layer sediments come to the surface in few areas. The tectonic movements and activity of mud volcanoes (active or buried) have left characteristic traces in the geological structure of the research area. Brachianticlinal and other types of structures were formed here. Under the strong influence of tectonic movements, the layers forming them were deformed and broken into blocks by regional tectonic faults. The anticlinal structures of the zone are complicated by longitudinal and latitudinal faults. The Mishovdag fold is represented by a brachianticline, 20-25 km long and 4-6 km wide. Brachianticline has a sharply asymmet- rical structure. The southwestern limb is steep, and inclined at an angle of 25-450, while the northeastern limb is flat and characterized by an inclination angle of 7-250. As a result of the analysis of the cross-sections of deep wells drilled in the field, it was determined that Mesozoic, Paleogene-Miocene, and Pliocene-Anthropogenic sediments are developed in the section of the fold. Sediments repre- senting the cross-section are characterized by high reservoir properties. Geological-geophysical works are carried out in the field. Core materials were taken from wells. The lithological-petrophysical characteristics – carbonate, porosity, and permeability of reservoir rocks have been determined according to core samples taken from exploration wells drilled in the field. The lithological-petrophysical characteristic regularities of change were investigated depending on depth.
 
 

Seismological research in Yunnan Province, China, and its tectonic implication between the Xianshuihe-Xiaojiang fault system and the Red River fault zone

The tectonic crosscutting relationship between the two most tectonic important Xianshuihe-Xiaojiang fault system (XFS) and the Red River fault zone (RRF) is a key basic problem but it is controversial now. These obscure further leads to a hot argument about the geodynamic model of the southeast margin of the Tibetan Plateau. In order to answer whether the XFS has cut across the RRF and extended southwardly, multiple seismological methods, including seismic relocation, b-value analysis, seismic energy, density study, focal mechanism inversion, and regional stress field research, are applied in the Yunnan Province area, China, where the XFS and the RRF intersects with each other. The results comprehensively demonstrate that the southern segment of the XFS has not been affected by the RRF, and it has continued for a length after crossing the RRF, but the Dian Bien Phu fault zone should not be an extension fault of the XFS. Along the SW direction, starting from the middle segment of the XFS, and cutting across the Qujiang fault, Shiping-Jianshui fault zone, RRF, Ailaoshan fault zone, Wuliangshan fault zone, and the southern section of the Daluo fault, the belt should be treated as the eastern boundary of the clockwise rotational in geodynamics model of the Tibetan Plateau in this study area. Based on these conclusion above and previous recognitions, a new geodynamic evolution model is proposed.