Layering detection is an important step in petroleum engineering.Time series of post-stack seismic data and wire-line log data belong to subsurface layering.They exhibit multifractal properties with complex patterns b...Layering detection is an important step in petroleum engineering.Time series of post-stack seismic data and wire-line log data belong to subsurface layering.They exhibit multifractal properties with complex patterns because of the heterogeneity and different genetic properties in the earth layers.In a multifractal configuration,any piece of a series has a distinct Hurst exponent that reflects its nature and can be used for zone detection.Time series are post-stack seismic traces and wire-line log data near the well-bores.Self-similar Autoregressive Exogenous(SAE)model is a modified method which can place self-similar post-stack seismic and wire-line log segments across layers with the same lithology.The results satisfy the capability of layering identification from seismic data by SAE model.展开更多
The 2025 M_(w)7.7 Myanmar earthquake highlighted the challenge of near-fault seismic intensity field reconstruction due to sparse seismic networks.To address this limitation,a framework was proposed integrating seismi...The 2025 M_(w)7.7 Myanmar earthquake highlighted the challenge of near-fault seismic intensity field reconstruction due to sparse seismic networks.To address this limitation,a framework was proposed integrating seismic wave simulation with a data-constrained finite-fault rupture model.The constraint is implemented by identifying the optimal ground motion models(GMMs)through a scoring system that selects the best-fit GMMs to mid-and far-field China Earthquake Networks Center(CENC)seismic network data;and applying the optimal GMMs to refine the rupture model parameters for near-fault intensity field simulation.The simulated near-fault seismic intensity field reproduces seismic intensities collected from Myanmar’s sparse seismic network and concentrated in≥Ⅷintensity zones within 50 km of the projected fault plane;and identifies abnormal intensity regions exhibiting≥Ⅹintensity along the Meiktila-Naypyidaw corridor and near Shwebo that are attributed to soft soil amplification effects and near-fault directivity.This framework can also be applied to post-earthquake assessments in other similar regions.展开更多
Earthquakes pose significant perils to the built environment in urban areas.To avert the calamitous aftermath of earthquakes,it is imperative to construct seismic resilient cities.Due to the intricacy of the concept o...Earthquakes pose significant perils to the built environment in urban areas.To avert the calamitous aftermath of earthquakes,it is imperative to construct seismic resilient cities.Due to the intricacy of the concept of urban seismic resilience(USR),its assessment is a large-scale system engineering issue.The assessment of USR should be based on the notion of urban seismic capacity(USC)assessment,which includes casualties,economic loss,and recovery time as criteria.Functionality loss is also included in the assessment of USR in addition to these criteria.The assessment indicator system comprising five dimensions(building and lifeline infrastructure,environment,society,economy,and institution)and 20 indicators has been devised to quantify USR.The analytical hierarchy process(AHP)is utilized to compute the weights of the criteria,dimensions,and indicators in the urban seismic resilience assessment(USRA)indicator system.When the necessary data for a city are obtainable,the seismic resilience of that city can be assessed using this framework.To illustrate the proposed methodology,a moderate-sized city in China was selected as a case study.The assessment results indicate a high level of USR,suggesting that the city possesses strong capabilities to withstand and recover from potential future earthquakes.展开更多
Dispatched by the Chinese government,a multidisciplinary team of 30 researchers collaborated with a team from Myanmar to conduct a 14-day on-site investigation.The work encompassed seismic intensity assessments,field ...Dispatched by the Chinese government,a multidisciplinary team of 30 researchers collaborated with a team from Myanmar to conduct a 14-day on-site investigation.The work encompassed seismic intensity assessments,field surveys,and loss evaluations.The paper focuses on the intensity distribution and structural damage characteristics of the 2025 M7.9 Myanmar earthquake,yielding the following key findings.(1)The seismogenic fault rupture propagated in a nearly N-S direction,with a surface rupture length of approximately 450 km.The seismic impact zone exhibited an elongated N-S distribution and a shorter E-W span,distributed like a belt around the seismogenic fault.(2)Within the seismic impact zones,existing buildings comprised five primary structural types,with timber(bamboo)structures constituting the largest proportion(≈80%in rural areas,≈50%in urban areas).The relatively low disaster losses and casualties were primarily attributable to the good seismic performance and low damage ratio of timber(bamboo)structures across varying intensity zones.(3)An anomalous zone of intensityⅨwas located at the boundary between intensityⅥandⅦregions in Nay Pyi Taw.Here,ridge topography combined with soft soil layers significantly amplified ground motion,exacerbating structural damage.(4)Directional effects of ground motion were observed,with the structural damage phenomena and peak ground acceleration(PGA)values in the N-S direction exceeding those in the E-W direction.This validates that the maximum PGA distribution of strike-slip fault earthquakes aligns with the fault strike.The research is expected to provide technical support for post-disaster reconstruction planning,site selection,and disaster mitigation strategies in Myanmar.展开更多
To quantify the seismic resilience of buildings,a method for evaluating functional loss from the component level to the overall building is proposed,and the dual-parameter seismic resilience assessment method based on...To quantify the seismic resilience of buildings,a method for evaluating functional loss from the component level to the overall building is proposed,and the dual-parameter seismic resilience assessment method based on postearthquake loss and recovery time is improved.A threelevel function tree model is established,which can consider the dynamic changes in weight coefficients of different category of components relative to their functional losses.Bayesian networks are utilized to quantify the impact of weather conditions,construction technology levels,and worker skill levels on component repair time.A method for determining the real-time functional recovery curve of buildings based on the component repair process is proposed.Taking a three-story teaching building as an example,the seismic resilience indices under basic earthquakes and rare earthquakes are calculated.The results show that the seismic resilience grade of the teaching building is comprehensively judged as GradeⅢ,and its resilience grade is more significantly affected by postearthquake loss.The proposed method can be used to predict the seismic resilience of buildings prior to earthquakes,identify weak components within buildings,and provide guidance for taking measures to enhance the seismic resilience of buildings.展开更多
Source properties and stress fields are critical to understand fundamental mechanisms for fluid-induced earthquakes.In this study,we identify the focal mechanism solutions(FMSs)of 360 earthquakes with local magnitude ...Source properties and stress fields are critical to understand fundamental mechanisms for fluid-induced earthquakes.In this study,we identify the focal mechanism solutions(FMSs)of 360 earthquakes with local magnitude M_(L)≥1.5 in the Changning shale gas field from January 2016 to May 2017 by fitting three-component waveforms.We then constrain the directions of the maximum horizontal stress(σ_(H_(max)))for four dense earthquake clusters using the stress tensor inversion method.The stress drops of 121 earthquakes with M_(L)≥1.5 are calculated using the spectral ratio method.We examine the spatiotemporal heterogeneity of stress field,and discuss the cause of non-double-couple(non-DC)components in seismicity clusters.Following the Mohr-Coulomb criterion,we estimate the fluid overpressure thresholds from FMS for different seismic clusters,providing insights into potential physical mechanisms for induced seismicity.The FMS results indicate that shallow reverse earthquakes,with steep dip angles,characterize most events.The source mechanisms of earthquakes with M_(L)≥1.5 are dominated by DC components(>70%),but several earthquakes with M_(L)>3.0 and the microseismic events nearby during injection period display significant non-DC components(>30%).Stress inversion results reveal that the σ_(H_(max)) direction ranges from 120°to 128°.Stress drops of earthquakes range between 0.10 and 64.49 MPa,with high values occurring on reverse faults situated at a greater distance from the shale layer,accompanied by a moderate rotation(≤25°)in the trend of σ_(H_(max)).The seismic clusters close to the shale layer exhibit low fluid overpressure thresholds,prone to being triggered by high pore-pressure fluid.The integrated results suggest that the diffusion of high pore pressures is likely to be the primary factor for observed earthquakes.The present results are expected to offer valuable insights into the origin of anomalous seismicity near the shale gas sites.展开更多
Discrete fracture network(DFN)commonly existing in natural rock masses plays an important role in geological complexity which can influence rock fracturing behaviour during fluid injection.This paper simulated the hyd...Discrete fracture network(DFN)commonly existing in natural rock masses plays an important role in geological complexity which can influence rock fracturing behaviour during fluid injection.This paper simulated the hydraulic fracturing process in lab-scale coal samples with DFNs and the induced seismic activities by the discrete element method(DEM).The effects of DFNs on hydraulic fracturing,induced seismicity and elastic property changes have been concluded.Denser DFNs can comprehensively decrease the peak injection pressure and injection duration.The proportion of strong seismic events increases first and then decreases with increasing DFN density.In addition,the relative modulus of the rock mass is derived innovatively from breakdown pressure,breakdown fracture length and the related initiation time.Increasing DFN densities among large(35–60 degrees)and small(0–30 degrees)fracture dip angles show opposite evolution trends in relative modulus.The transitional point(dip angle)for the opposite trends is also proportionally affected by the friction angle of the rock mass.The modelling results have much practical meaning to infer the density and geometry of pre-existing fractures and the elastic property of rock mass in the field,simply based on the hydraulic fracturing and induced seismicity monitoring data.展开更多
The three-dimensional(3D)geometry of a fault is a critical control on earthquake nucleation,dynamic rupture,stress triggering,and related seismic hazards.Therefore,a 3D model of an active fault can significantly impro...The three-dimensional(3D)geometry of a fault is a critical control on earthquake nucleation,dynamic rupture,stress triggering,and related seismic hazards.Therefore,a 3D model of an active fault can significantly improve our understanding of seismogenesis and our ability to evaluate seismic hazards.Utilising the SKUA GoCAD software,we constructed detailed seismic fault models for the 2021 M_(S)6.4 Yangbi earthquake in Yunnan,China,using two sets of relocated earthquake catalogs and focal mechanism solutions following a convenient 3D fault modeling workflow.Our analysis revealed a NW-striking main fault with a high-angle SW dip,accompanied by two branch faults.Interpretation of one dataset revealed a single NNW-striking branch fault SW of the main fault,whereas the other dataset indicated four steep NNE-striking segments with a left-echelon pattern.Additionally,a third ENE-striking short fault was identified NE of the main fault.In combination with the spatial distribution of pre-existing faults,our 3D fault models indicate that the Yangbi earthquake reactivated pre-existing NW-and NE-striking fault directions rather than the surface-exposed Weixi-Qiaohou-Weishan Fault zone.The occurrence of the Yangbi earthquake demonstrates that the reactivation of pre-existing faults away from active fault zones,through either cascade or conjugate rupture modes,can cause unexpected moderate-large earthquakes and severe disasters,necessitating attention in regions like southeast Xizang,which have complex fault systems.展开更多
Saline aquifers are considered as highly favored reservoirs for CO_(2)sequestration due to their favorable properties.Understanding the impact of saline aquifer properties on the migration and distribution of CO_(2)pl...Saline aquifers are considered as highly favored reservoirs for CO_(2)sequestration due to their favorable properties.Understanding the impact of saline aquifer properties on the migration and distribution of CO_(2)plume is crucial.This study focuses on four key parameters-permeability,porosity,formation pressure,and temperature-to characterize the reservoir and analyse the petrophysical and elastic response of CO_(2).First,we performed reservoir simulations to simulate CO_(2)saturation,using multiple sets of these four parameters to examine their significance on CO_(2)saturation and the plume migration speed.Subsequently,the effect of these parameters on the elastic properties is tested using rock physics theory.We established a relationship of compressional wave velocity(V_(p))and quality factor(Q_(p))with the four key parameters,and conducted a sensitivity analysis to test their sensitivity to V_(p) and Q_(p).Finally,we utilized visco-acoustic wave equation simulated time-lapse seismic data based on the computed V_(p) and Q_(p) models,and analysed the impact of CO_(2) saturation changes on seismic data.As for the above nu-merical simulations and analysis,we conducted sensitivity analysis using both homogeneous and heterogeneous models.Consistent results are found between homogeneous and heterogeneous models.The permeability is the most sensitive parameter to the CO_(2)saturation,while porosity emerges as the primary factor affecting both Q_(p) and V_(p).Both Q_(p) and V_(p) increase with the porosity,which contradicts the observations in gas reservoirs.The seismic simulations highlight significant variations in the seismic response to different parameters.We provided analysis for these observations,which serves as a valuable reference for comprehensive CO_(2)integrity analysis,time-lapse monitoring,injection planning and site selection.展开更多
The southern region of Saudi Arabia exhibits a distinct seismic profile shaped by the Red Sea Rift and local fault systems, necessitating rigorous seismic hazard evaluations and tailored structural design strategies. ...The southern region of Saudi Arabia exhibits a distinct seismic profile shaped by the Red Sea Rift and local fault systems, necessitating rigorous seismic hazard evaluations and tailored structural design strategies. This study applies a robust Probabilistic Seismic Hazard Analysis (PSHA) framework to compute Maximum Considered Earthquake (MCE) and Risk-Targeted Maximum Considered Earthquake (MCER) values for major cities, including Jazan, Abha, and Najran. Utilizing local seismotectonic models, ground motion prediction equations (GMPEs), and soil classifications, the study generates precise ground motion parameters critical for infrastructure planning and safety. Results indicate significant seismic hazard variability, with Jazan showing high seismic risks with an MCER SA (0.2 s) of 0.45 g, compared to Najran’s lower risks at 0.23 g. Structural design guidelines, informed by MCE and MCER calculations, prioritize the integration of site-specific seismic data, enhanced ductility requirements, and advanced analytical methods to ensure resilient and sustainable infrastructure. The study underscores the necessity of localized seismic assessments and modern engineering practices to effectively mitigate seismic risks in this geologically complex region.展开更多
Studying the inner structure of intraplate earthquakes originating in aseismic areas,which are poorly covered by seismic networks or as historical earthquakes is usually the only way to get knowledge about their sourc...Studying the inner structure of intraplate earthquakes originating in aseismic areas,which are poorly covered by seismic networks or as historical earthquakes is usually the only way to get knowledge about their source mechanisms,which is partially essential for a deeper understanding of intraplate geodynamics.The epicentral zones of earthquakes are situated in hard-toreach areas,so,using active seismic methods for such purposes is unreasonable or even impossible because of high cost and logistical difficulties.We propose a novel approach that combines diverse passive seismic methods,which allows us to get sufficient information about geological environment structure for such task solutions.As an example,we investigated the inner structure of platform earthquake epicentral zone originated up north of Russia.We used four passive seismic methods:microseismic sounding method,passive seismic interferometry,HVSR method,and microseismic activity method.We show that passive seismic data,recoded in the same installation and processed by these different methods,can provide sufficient information about structure of studied environment,needed to explain source mechanism.In sum,the hypocenter zone is presented by intersection of vertical faults and a lateral fractured zone in the middle crust.Results were confirmed by comparison with results by active seismic methods.展开更多
The Longmenshan(LMS)fault zone is located at the junction of the eastern Tibetan Plateau and the Sichuan Basin and is of great significance for studying regional tectonics and earthquake hazards.Although regional velo...The Longmenshan(LMS)fault zone is located at the junction of the eastern Tibetan Plateau and the Sichuan Basin and is of great significance for studying regional tectonics and earthquake hazards.Although regional velocity models are available for the LMS fault zone,high-resolution velocity models are lacking.Therefore,a dense array of 240 short-period seismometers was deployed around the central segment of the LMS fault zone for approximately 30 days to monitor earthquakes and characterize fine structures of the fault zone.Considering the large quantity of observed seismic data,the data processing workflow consisted of deep learning-based automatic earthquake detection,phase arrival picking,and association.Compared with the earthquake catalog released by the China Earthquake Administration,many more earthquakes were detected by the dense array.Double-difference seismic tomography was adopted to determine V_(p),V_(s),and V_(p)/V_(s)models as well as earthquake locations.The checkerboard test showed that the velocity models have spatial resolutions of approximately 5 km in the horizontal directions and 2 km at depth.To the west of the Yingxiu–Beichuan Fault(YBF),the Precambrian Pengguan complex,where most of earthquakes occurred,is characterized by high velocity and low V_(p)/V_(s)values.In comparison,to the east of the YBF,the Upper Paleozoic to Jurassic sediments,where few earthquakes occurred,show low velocity and high V_(p)/V_(s)values.Our results suggest that the earthquake activity in the LMS fault zone is controlled by the strength of the rock compositions.When the high-resolution velocity models were combined with the relocated earthquakes,we were also able to delineate the fault geometry for different faults in the LMS fault zone.展开更多
The Chilean subduction zone is one of the most seismically active regions globally,characterized by extensive intermediatedepth seismicity in the slab.In this study,we construct a new earthquake catalog for northern C...The Chilean subduction zone is one of the most seismically active regions globally,characterized by extensive intermediatedepth seismicity in the slab.In this study,we construct a new earthquake catalog for northern Chile using seismic waveforms assembled for the period of 2014-2019,from which 320,070 P-wave and 232,907 S-wave first arrivals are obtained for 25,763 earthquakes.Grid search location method NonLinLoc is applied to determine initial earthquake locations and double-difference location method is used to improve relative event locations.The distribution of earthquakes exhibits distinct patterns to the north and south of 21°S.There are many more earthquakes deeper than~150 km to the south of 21°S,while relatively fewer to the north.The intraslab earthquakes shallower than~80 km generally reveal a distinct double seismic zone,and the gap between the two seismic planes disappears at a depth of approximately~80 km,followed by a concentration of seismicity in the depth range of~80-150 km.In the deeper slab,there exist several seismicity clusters with distinct earthquake activities down to~300 km.These characteristics shown in slab seismicity are likely caused by different mechanisms and can be helpful for understanding the subduction process.展开更多
The occurrence time and magnitude of injection-induced seismicity are influenced by engineering factors,such as wellhead pressure,injection location,injection volume,and injection rate.Understanding the relationship b...The occurrence time and magnitude of injection-induced seismicity are influenced by engineering factors,such as wellhead pressure,injection location,injection volume,and injection rate.Understanding the relationship between injection operations and seismic magnitude is of great significance for optimizing industrial production and reducing earthquake disasters.Numerical simulation of hydromechanical coupling is a crucial method for studying injection-induced seismicity.However,few studies have explored the risk management measures for injection-induced seismicity from the perspective of engineering.How seismic magnitudes can be reduced through reasonable adjustments to injection operations in engineering remains unclear.Therefore,in this study,a 3D hydro-mechanical coupling model involving multiple faults and injection wells was established based on the geological background and well location of Fox Creek,Canada.Different injection schemes under multi-well and multi-fault conditions were studied,and a traffic light system was used to simulate and control the magnitudes under a multi-well injection scheme.Specifically,we simulated injection scenarios involving up to three wells and analyzed the response of five faults.We compared the maximum moment magnitude of different scenarios by controlling the same injection volume.The results revealed the effect and advantage of the multi-well scheme in reducing seismic magnitude.To reduce the risk of induced seismicity,utilizing far-fault operational wells to compensate for the effects of near-fault operational wells proves to be an efficient and cost-effective method,with potential for wide practical applications.展开更多
A seismic swarm occurred southeast of King George Island,South Shetland Islands,Antarctica,between August 2020 and February 2021.This work intends to parameterize seismic events recorded by seismic station AM.R4DE2 fr...A seismic swarm occurred southeast of King George Island,South Shetland Islands,Antarctica,between August 2020 and February 2021.This work intends to parameterize seismic events recorded by seismic station AM.R4DE2 from 15 September to 31 October 2020.Using the localization methodology with a single station,the record of the entire period was analyzed manually to determine the local magnitude,hypocentral distance,epicentral distance,backazimuth,and location of the epicenter for each event.We could parameterize 6362 events,although we estimate the occurrence to be around 20000 for the period.The results suggest a magmatic origin for the swarm,supporting previous studies.Seismicity exhibited a southeastward migration away from King George Island,as indicated by a progressive increase in epicentral distance over time.Most events were classified as volcanic and volcano-tectonic,supporting a magmatogenesis hypothesis linked to the opening of Bransfield Ridge.展开更多
Triggered seismicity is a key hazard where fluids are injected or withdrawn from the subsurface and may impact permeability. Understanding the mechanisms that control fluid injection-triggered seismicity allows its mi...Triggered seismicity is a key hazard where fluids are injected or withdrawn from the subsurface and may impact permeability. Understanding the mechanisms that control fluid injection-triggered seismicity allows its mitigation. Key controls on seismicity are defined in terms of fault and fracture strength, second-order frictional response and stability, and competing fluid-driven mechanisms for arrest. We desire to constrain maximum event magnitudes in triggered earthquakes by relating pre-existing critical stresses to fluid injection volume to explain why some recorded events are significantly larger than anticipated seismic moment thresholds. This formalism is consistent with several uncharacteristically large fluid injection-triggered earthquakes. Such methods of reactivating fractures and faults by hydraulic stimulation in shear or tensile fracturing are routinely used to create permeability in the subsurface. Microearthquakes (MEQs) generated by such stimulations can be used to diagnose permeability evolution. Although high-fidelity data sets are scarce, the EGS-Collab and Utah FORGE hydraulic stimulation field demonstration projects provide high-fidelity data sets that concurrently track permeability evolution and triggered seismicity. Machine learning deciphers the principal features of MEQs and the resulting permeability evolution that best track permeability changes – with transfer learning methods allowing robust predictions across multiple eological settings. Changes in permeability at reactivated fractures in both shear and extensional modes suggest that permeability change (Δk) scales with the seismic moment (M) of individual MEQs as Δk∝M. This scaling relation is exact at early times but degrades with successive MEQs, but provides a method for characterizing crustal permeability evolution using MEQs, alone. Importantly, we quantify for the first time the role of prestress in defining the elevated magnitude and seismic moment of fluid injection-triggered events, and demonstrate that such MEQs can also be used as diagnostic in quantifying permeability evolution in the crust.展开更多
Mining-related seismicity poses significant challenges in underground coal mining due to its complex rupture mechanisms and associated hazards.To bridge gaps in understanding these intricate processes,this study emplo...Mining-related seismicity poses significant challenges in underground coal mining due to its complex rupture mechanisms and associated hazards.To bridge gaps in understanding these intricate processes,this study employed a multi-local seismic monitoring network,integrating both in-mine and local instruments at overlapping length scales.We specifically focused on a damaging local magnitude(ML)2.6 event and its aftershocks that occurred on 10 September 2022 in the vicinity of the 3308 working face of the Yangcheng coal mine in Shandong Province,China.Moment tensor(MT)inversion revealed a complex cascading rupture mechanism:an initial moment magnitude(M_(w))2.2 normal fault slip along the DF60 fault in an ESEeWNW direction,transitioning to a M_(w)3.0 event as the FD24 and DF60 faults unclamped.The scale-independent self-similarity and stress heterogeneity of mining-related seismicity were investigated through source parameter calculations,providing valuable insights into the driving mechanism of these seismic sequences.The in-mine network,constrained by its low dynamic changes,captured only the nucleation phase of the DF60 fault.Furthermore,standard decomposition of the MT solution from the seismic network proved inadequate for accurately identifying the complex nature of the rupture.To enhance safety and risk management in mining environments,we examined the implications of source reactivation within the cluster area post-stress-adjustment.This comprehensive multiscale analysis offers crucial insights into the complex rupture mechanisms and hazards associated with mining-related seismicity.The results underscore the importance of continuous multi-local network monitoring and advanced analytical techniques for improved disaster assessment and risk mitigation in mining operations.展开更多
This work focuses on enhancing low frequency seismic data using a convolutional neural network trained on synthetic data.Traditional seismic data often lack both high and low frequencies,which are essential for detail...This work focuses on enhancing low frequency seismic data using a convolutional neural network trained on synthetic data.Traditional seismic data often lack both high and low frequencies,which are essential for detailed geological interpretation and various geophysical applications.Low frequency data is particularly valuable for reducing wavelet sidelobes and improving full waveform inversion(FWI).Conventional methods for bandwidth extension include seismic deconvolution and sparse inversion,which have limitations in recovering low frequencies.The study explores the potential of the U-net,which has been successful in other geophysical applications such as noise attenuation and seismic resolution enhancement.The novelty in our approach is that we do not rely on computationally expensive finite difference modelling to create training data.Instead,our synthetic training data is created from individual randomly perturbed events with variations in bandwidth,making it more adaptable to different data sets compared to previous deep learning methods.The method was tested on both synthetic and real seismic data,demonstrating effective low frequency reconstruction and sidelobe reduction.With a synthetic full waveform inversion to recover a velocity model and a seismic amplitude inversion to estimate acoustic impedance we demonstrate the validity and benefit of the proposed method.Overall,the study presents a robust approach to seismic bandwidth extension using deep learning,emphasizing the importance of diverse and well-designed but computationally inexpensive synthetic training data.展开更多
With the advancement of fracturing technologies in deeper and more geologically complex formations,fault reactivation and induced seismicity have attracted increasing attention.The increasing frequency and magnitude o...With the advancement of fracturing technologies in deeper and more geologically complex formations,fault reactivation and induced seismicity have attracted increasing attention.The increasing frequency and magnitude of these events underscore the need for a robust understanding of the governing physical mechanisms.Elevated pore pressure,modified fault-loading conditions,and aseismic slip are widely acknowledged as the primary drivers.Recent studies have explored these mechanisms under varying factors,including fluid properties,rock ductility,poroelastic responses,and evolving fault stress states,thereby offering critical insights into model refinement.Probabilistic forecasting approaches,which combine statistical analyses of historical data with real-time monitoring,are being increasingly adopted in seismic risk assessments.In parallel,machine learning techniques are employed to process large seismic datasets and identify key patterns.However,their predictive capabilities remain limited by geological heterogeneity,subsurface complexity,and scarce observational data.Moreover,fluid–rock interactions further complicate the development of universally applicable models,thereby constraining the generalizability of mitigation strategies.This review synthesizes the current understanding of induced seismicity mechanisms,evaluates the prevailing prediction and mitigation methods,and identifies major challenges and future research directions.Advancements in these areas are essential to enhancing seismic risk management and ensuring the safe,sustainable development of deep-subsurface energy resources.展开更多
To analyze the triggering relationship of historical earthquakes to the 2023 Jishishan earthquake and estimate the seismic risk in the adjacent region after the earthquake,we calculate the evolution process of seismic...To analyze the triggering relationship of historical earthquakes to the 2023 Jishishan earthquake and estimate the seismic risk in the adjacent region after the earthquake,we calculate the evolution process of seismic stress generated by 11 earthquakes with MS≥6.0 and 1 earthquake with MS5.7 near the source in the past 100 years.The results show that before the 2023 Jishishan earthquake,the entire Lajishan Northern Edge Fault zone was under the stress shadow generated by the 12 earthquakes.The stress reduction at the 2023 Jishishan earthquake epicenter was approximately 15.1 kPa,and the contribution of this stress shadow mainly comes from the 1920 MS8.5 Haiyuan earthquake.The coseismic stress drop at the epicenter was around-292.1 kPa,and the maximum stress drop for the 2023 Jishishan earthquake was around-346.2 kPa.The Jishishan earthquake increased the stress of the two seismic gaps in the Lajishan Northern Edge Fault by 14.7 kPa and 59.7 k Pa respectively,the stress on the Lajishan Southern Edge Fault zone increased by 10.9 kPa,and the stress on the east section of Xunhua Nanshan Fault increased by 11.1 kPa.These stress increments potentially elevate the seismic hazard along these fault zones.In the future earthquake prevention and disaster reduction,attention should be paid to the seismic risk of these fault zones.展开更多
文摘Layering detection is an important step in petroleum engineering.Time series of post-stack seismic data and wire-line log data belong to subsurface layering.They exhibit multifractal properties with complex patterns because of the heterogeneity and different genetic properties in the earth layers.In a multifractal configuration,any piece of a series has a distinct Hurst exponent that reflects its nature and can be used for zone detection.Time series are post-stack seismic traces and wire-line log data near the well-bores.Self-similar Autoregressive Exogenous(SAE)model is a modified method which can place self-similar post-stack seismic and wire-line log segments across layers with the same lithology.The results satisfy the capability of layering identification from seismic data by SAE model.
基金Scientific Research Fund of Institute of Engineering Mechanics,China Earthquake Administration under Grant No.2023C01National Natural Science Foundation of China under Grant No.52478570Distinguished Young Scholars Program of the Natural Science Foundation of Heilongjiang Province,China under Grant No.JQ2024E002。
文摘The 2025 M_(w)7.7 Myanmar earthquake highlighted the challenge of near-fault seismic intensity field reconstruction due to sparse seismic networks.To address this limitation,a framework was proposed integrating seismic wave simulation with a data-constrained finite-fault rupture model.The constraint is implemented by identifying the optimal ground motion models(GMMs)through a scoring system that selects the best-fit GMMs to mid-and far-field China Earthquake Networks Center(CENC)seismic network data;and applying the optimal GMMs to refine the rupture model parameters for near-fault intensity field simulation.The simulated near-fault seismic intensity field reproduces seismic intensities collected from Myanmar’s sparse seismic network and concentrated in≥Ⅷintensity zones within 50 km of the projected fault plane;and identifies abnormal intensity regions exhibiting≥Ⅹintensity along the Meiktila-Naypyidaw corridor and near Shwebo that are attributed to soft soil amplification effects and near-fault directivity.This framework can also be applied to post-earthquake assessments in other similar regions.
基金supported by the National Key R&D Program of China(No.2023YFC3805100)the National Natural Science Foundation of China(Nos.52222811 and 52494963)。
文摘Earthquakes pose significant perils to the built environment in urban areas.To avert the calamitous aftermath of earthquakes,it is imperative to construct seismic resilient cities.Due to the intricacy of the concept of urban seismic resilience(USR),its assessment is a large-scale system engineering issue.The assessment of USR should be based on the notion of urban seismic capacity(USC)assessment,which includes casualties,economic loss,and recovery time as criteria.Functionality loss is also included in the assessment of USR in addition to these criteria.The assessment indicator system comprising five dimensions(building and lifeline infrastructure,environment,society,economy,and institution)and 20 indicators has been devised to quantify USR.The analytical hierarchy process(AHP)is utilized to compute the weights of the criteria,dimensions,and indicators in the urban seismic resilience assessment(USRA)indicator system.When the necessary data for a city are obtainable,the seismic resilience of that city can be assessed using this framework.To illustrate the proposed methodology,a moderate-sized city in China was selected as a case study.The assessment results indicate a high level of USR,suggesting that the city possesses strong capabilities to withstand and recover from potential future earthquakes.
基金National Natural Science Foundation of China under Grant No.U2239252National Natural Science Foundation of China under Grant No.52279128Natural Science Foundation of Heilongjiang Province of China under Grant No.YQ2022E013。
文摘Dispatched by the Chinese government,a multidisciplinary team of 30 researchers collaborated with a team from Myanmar to conduct a 14-day on-site investigation.The work encompassed seismic intensity assessments,field surveys,and loss evaluations.The paper focuses on the intensity distribution and structural damage characteristics of the 2025 M7.9 Myanmar earthquake,yielding the following key findings.(1)The seismogenic fault rupture propagated in a nearly N-S direction,with a surface rupture length of approximately 450 km.The seismic impact zone exhibited an elongated N-S distribution and a shorter E-W span,distributed like a belt around the seismogenic fault.(2)Within the seismic impact zones,existing buildings comprised five primary structural types,with timber(bamboo)structures constituting the largest proportion(≈80%in rural areas,≈50%in urban areas).The relatively low disaster losses and casualties were primarily attributable to the good seismic performance and low damage ratio of timber(bamboo)structures across varying intensity zones.(3)An anomalous zone of intensityⅨwas located at the boundary between intensityⅥandⅦregions in Nay Pyi Taw.Here,ridge topography combined with soft soil layers significantly amplified ground motion,exacerbating structural damage.(4)Directional effects of ground motion were observed,with the structural damage phenomena and peak ground acceleration(PGA)values in the N-S direction exceeding those in the E-W direction.This validates that the maximum PGA distribution of strike-slip fault earthquakes aligns with the fault strike.The research is expected to provide technical support for post-disaster reconstruction planning,site selection,and disaster mitigation strategies in Myanmar.
基金The National Key Research and Development Program of China(No.2023YFC3805003)。
文摘To quantify the seismic resilience of buildings,a method for evaluating functional loss from the component level to the overall building is proposed,and the dual-parameter seismic resilience assessment method based on postearthquake loss and recovery time is improved.A threelevel function tree model is established,which can consider the dynamic changes in weight coefficients of different category of components relative to their functional losses.Bayesian networks are utilized to quantify the impact of weather conditions,construction technology levels,and worker skill levels on component repair time.A method for determining the real-time functional recovery curve of buildings based on the component repair process is proposed.Taking a three-story teaching building as an example,the seismic resilience indices under basic earthquakes and rare earthquakes are calculated.The results show that the seismic resilience grade of the teaching building is comprehensively judged as GradeⅢ,and its resilience grade is more significantly affected by postearthquake loss.The proposed method can be used to predict the seismic resilience of buildings prior to earthquakes,identify weak components within buildings,and provide guidance for taking measures to enhance the seismic resilience of buildings.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.U20A20266 and 12302503)Scientific and technological research projects in Sichuan province(Grant No.2024NSFSC0973).
文摘Source properties and stress fields are critical to understand fundamental mechanisms for fluid-induced earthquakes.In this study,we identify the focal mechanism solutions(FMSs)of 360 earthquakes with local magnitude M_(L)≥1.5 in the Changning shale gas field from January 2016 to May 2017 by fitting three-component waveforms.We then constrain the directions of the maximum horizontal stress(σ_(H_(max)))for four dense earthquake clusters using the stress tensor inversion method.The stress drops of 121 earthquakes with M_(L)≥1.5 are calculated using the spectral ratio method.We examine the spatiotemporal heterogeneity of stress field,and discuss the cause of non-double-couple(non-DC)components in seismicity clusters.Following the Mohr-Coulomb criterion,we estimate the fluid overpressure thresholds from FMS for different seismic clusters,providing insights into potential physical mechanisms for induced seismicity.The FMS results indicate that shallow reverse earthquakes,with steep dip angles,characterize most events.The source mechanisms of earthquakes with M_(L)≥1.5 are dominated by DC components(>70%),but several earthquakes with M_(L)>3.0 and the microseismic events nearby during injection period display significant non-DC components(>30%).Stress inversion results reveal that the σ_(H_(max)) direction ranges from 120°to 128°.Stress drops of earthquakes range between 0.10 and 64.49 MPa,with high values occurring on reverse faults situated at a greater distance from the shale layer,accompanied by a moderate rotation(≤25°)in the trend of σ_(H_(max)).The seismic clusters close to the shale layer exhibit low fluid overpressure thresholds,prone to being triggered by high pore-pressure fluid.The integrated results suggest that the diffusion of high pore pressures is likely to be the primary factor for observed earthquakes.The present results are expected to offer valuable insights into the origin of anomalous seismicity near the shale gas sites.
基金Australian Research Council Linkage Program(LP200301404)for sponsoring this researchthe financial support provided by the State Key Laboratory of Geohazard Prevention and Geoenvironment Protection(Chengdu University of Technology,SKLGP2021K002)National Natural Science Foundation of China(52374101,32111530138).
文摘Discrete fracture network(DFN)commonly existing in natural rock masses plays an important role in geological complexity which can influence rock fracturing behaviour during fluid injection.This paper simulated the hydraulic fracturing process in lab-scale coal samples with DFNs and the induced seismic activities by the discrete element method(DEM).The effects of DFNs on hydraulic fracturing,induced seismicity and elastic property changes have been concluded.Denser DFNs can comprehensively decrease the peak injection pressure and injection duration.The proportion of strong seismic events increases first and then decreases with increasing DFN density.In addition,the relative modulus of the rock mass is derived innovatively from breakdown pressure,breakdown fracture length and the related initiation time.Increasing DFN densities among large(35–60 degrees)and small(0–30 degrees)fracture dip angles show opposite evolution trends in relative modulus.The transitional point(dip angle)for the opposite trends is also proportionally affected by the friction angle of the rock mass.The modelling results have much practical meaning to infer the density and geometry of pre-existing fractures and the elastic property of rock mass in the field,simply based on the hydraulic fracturing and induced seismicity monitoring data.
基金financial support from the National Key R&D Program of China (No. 2021YFC3000600)National Natural Science Foundation of China (No. 41872206)National Nonprofit Fundamental Research Grant of China, Institute of Geology, China, Earthquake Administration (No. IGCEA2010)
文摘The three-dimensional(3D)geometry of a fault is a critical control on earthquake nucleation,dynamic rupture,stress triggering,and related seismic hazards.Therefore,a 3D model of an active fault can significantly improve our understanding of seismogenesis and our ability to evaluate seismic hazards.Utilising the SKUA GoCAD software,we constructed detailed seismic fault models for the 2021 M_(S)6.4 Yangbi earthquake in Yunnan,China,using two sets of relocated earthquake catalogs and focal mechanism solutions following a convenient 3D fault modeling workflow.Our analysis revealed a NW-striking main fault with a high-angle SW dip,accompanied by two branch faults.Interpretation of one dataset revealed a single NNW-striking branch fault SW of the main fault,whereas the other dataset indicated four steep NNE-striking segments with a left-echelon pattern.Additionally,a third ENE-striking short fault was identified NE of the main fault.In combination with the spatial distribution of pre-existing faults,our 3D fault models indicate that the Yangbi earthquake reactivated pre-existing NW-and NE-striking fault directions rather than the surface-exposed Weixi-Qiaohou-Weishan Fault zone.The occurrence of the Yangbi earthquake demonstrates that the reactivation of pre-existing faults away from active fault zones,through either cascade or conjugate rupture modes,can cause unexpected moderate-large earthquakes and severe disasters,necessitating attention in regions like southeast Xizang,which have complex fault systems.
基金supported by the State Key Laboratory of Offshore Oil and Gas Exploitation, Open Fund Project (No. CCL2023RCPS0162RQN)the primary funding, National Natural Science Foundation of China (No. ZX20230400)
文摘Saline aquifers are considered as highly favored reservoirs for CO_(2)sequestration due to their favorable properties.Understanding the impact of saline aquifer properties on the migration and distribution of CO_(2)plume is crucial.This study focuses on four key parameters-permeability,porosity,formation pressure,and temperature-to characterize the reservoir and analyse the petrophysical and elastic response of CO_(2).First,we performed reservoir simulations to simulate CO_(2)saturation,using multiple sets of these four parameters to examine their significance on CO_(2)saturation and the plume migration speed.Subsequently,the effect of these parameters on the elastic properties is tested using rock physics theory.We established a relationship of compressional wave velocity(V_(p))and quality factor(Q_(p))with the four key parameters,and conducted a sensitivity analysis to test their sensitivity to V_(p) and Q_(p).Finally,we utilized visco-acoustic wave equation simulated time-lapse seismic data based on the computed V_(p) and Q_(p) models,and analysed the impact of CO_(2) saturation changes on seismic data.As for the above nu-merical simulations and analysis,we conducted sensitivity analysis using both homogeneous and heterogeneous models.Consistent results are found between homogeneous and heterogeneous models.The permeability is the most sensitive parameter to the CO_(2)saturation,while porosity emerges as the primary factor affecting both Q_(p) and V_(p).Both Q_(p) and V_(p) increase with the porosity,which contradicts the observations in gas reservoirs.The seismic simulations highlight significant variations in the seismic response to different parameters.We provided analysis for these observations,which serves as a valuable reference for comprehensive CO_(2)integrity analysis,time-lapse monitoring,injection planning and site selection.
文摘The southern region of Saudi Arabia exhibits a distinct seismic profile shaped by the Red Sea Rift and local fault systems, necessitating rigorous seismic hazard evaluations and tailored structural design strategies. This study applies a robust Probabilistic Seismic Hazard Analysis (PSHA) framework to compute Maximum Considered Earthquake (MCE) and Risk-Targeted Maximum Considered Earthquake (MCER) values for major cities, including Jazan, Abha, and Najran. Utilizing local seismotectonic models, ground motion prediction equations (GMPEs), and soil classifications, the study generates precise ground motion parameters critical for infrastructure planning and safety. Results indicate significant seismic hazard variability, with Jazan showing high seismic risks with an MCER SA (0.2 s) of 0.45 g, compared to Najran’s lower risks at 0.23 g. Structural design guidelines, informed by MCE and MCER calculations, prioritize the integration of site-specific seismic data, enhanced ductility requirements, and advanced analytical methods to ensure resilient and sustainable infrastructure. The study underscores the necessity of localized seismic assessments and modern engineering practices to effectively mitigate seismic risks in this geologically complex region.
基金funded by the Russian Federation Ministry of Science and Higher Education according to the research project FUUW-2025-0033 of the FECIAR UrB RASthe Arkhangelsk branch of the Territorial Fund of Geological Information for the North-Western Federal District for providing geological and geophysical reports for the objects under consideration。
文摘Studying the inner structure of intraplate earthquakes originating in aseismic areas,which are poorly covered by seismic networks or as historical earthquakes is usually the only way to get knowledge about their source mechanisms,which is partially essential for a deeper understanding of intraplate geodynamics.The epicentral zones of earthquakes are situated in hard-toreach areas,so,using active seismic methods for such purposes is unreasonable or even impossible because of high cost and logistical difficulties.We propose a novel approach that combines diverse passive seismic methods,which allows us to get sufficient information about geological environment structure for such task solutions.As an example,we investigated the inner structure of platform earthquake epicentral zone originated up north of Russia.We used four passive seismic methods:microseismic sounding method,passive seismic interferometry,HVSR method,and microseismic activity method.We show that passive seismic data,recoded in the same installation and processed by these different methods,can provide sufficient information about structure of studied environment,needed to explain source mechanism.In sum,the hypocenter zone is presented by intersection of vertical faults and a lateral fractured zone in the middle crust.Results were confirmed by comparison with results by active seismic methods.
基金supported by the Scientific Research Foundation for High-level Talents of Anhui University of Science and Technology under Grant 2024yjrc64the National Key R&D Program of China under Grant 2018YFC1504102。
文摘The Longmenshan(LMS)fault zone is located at the junction of the eastern Tibetan Plateau and the Sichuan Basin and is of great significance for studying regional tectonics and earthquake hazards.Although regional velocity models are available for the LMS fault zone,high-resolution velocity models are lacking.Therefore,a dense array of 240 short-period seismometers was deployed around the central segment of the LMS fault zone for approximately 30 days to monitor earthquakes and characterize fine structures of the fault zone.Considering the large quantity of observed seismic data,the data processing workflow consisted of deep learning-based automatic earthquake detection,phase arrival picking,and association.Compared with the earthquake catalog released by the China Earthquake Administration,many more earthquakes were detected by the dense array.Double-difference seismic tomography was adopted to determine V_(p),V_(s),and V_(p)/V_(s)models as well as earthquake locations.The checkerboard test showed that the velocity models have spatial resolutions of approximately 5 km in the horizontal directions and 2 km at depth.To the west of the Yingxiu–Beichuan Fault(YBF),the Precambrian Pengguan complex,where most of earthquakes occurred,is characterized by high velocity and low V_(p)/V_(s)values.In comparison,to the east of the YBF,the Upper Paleozoic to Jurassic sediments,where few earthquakes occurred,show low velocity and high V_(p)/V_(s)values.Our results suggest that the earthquake activity in the LMS fault zone is controlled by the strength of the rock compositions.When the high-resolution velocity models were combined with the relocated earthquakes,we were also able to delineate the fault geometry for different faults in the LMS fault zone.
基金supported by National Natural Science Foundation of China(No.41861134009)the PIA ANID(AFB180004)the ANID(PCI PII-180003).
文摘The Chilean subduction zone is one of the most seismically active regions globally,characterized by extensive intermediatedepth seismicity in the slab.In this study,we construct a new earthquake catalog for northern Chile using seismic waveforms assembled for the period of 2014-2019,from which 320,070 P-wave and 232,907 S-wave first arrivals are obtained for 25,763 earthquakes.Grid search location method NonLinLoc is applied to determine initial earthquake locations and double-difference location method is used to improve relative event locations.The distribution of earthquakes exhibits distinct patterns to the north and south of 21°S.There are many more earthquakes deeper than~150 km to the south of 21°S,while relatively fewer to the north.The intraslab earthquakes shallower than~80 km generally reveal a distinct double seismic zone,and the gap between the two seismic planes disappears at a depth of approximately~80 km,followed by a concentration of seismicity in the depth range of~80-150 km.In the deeper slab,there exist several seismicity clusters with distinct earthquake activities down to~300 km.These characteristics shown in slab seismicity are likely caused by different mechanisms and can be helpful for understanding the subduction process.
基金funded by the Joint Funds of the National Natural Science Foundation of China(U23A20671)the Major Project of Inner Mongolia Science and Technology(2021ZD0034)the Open Research Fund of State Key Laboratory of Geomechanics and Geotechnical Engineering(No.Z021003)。
文摘The occurrence time and magnitude of injection-induced seismicity are influenced by engineering factors,such as wellhead pressure,injection location,injection volume,and injection rate.Understanding the relationship between injection operations and seismic magnitude is of great significance for optimizing industrial production and reducing earthquake disasters.Numerical simulation of hydromechanical coupling is a crucial method for studying injection-induced seismicity.However,few studies have explored the risk management measures for injection-induced seismicity from the perspective of engineering.How seismic magnitudes can be reduced through reasonable adjustments to injection operations in engineering remains unclear.Therefore,in this study,a 3D hydro-mechanical coupling model involving multiple faults and injection wells was established based on the geological background and well location of Fox Creek,Canada.Different injection schemes under multi-well and multi-fault conditions were studied,and a traffic light system was used to simulate and control the magnitudes under a multi-well injection scheme.Specifically,we simulated injection scenarios involving up to three wells and analyzed the response of five faults.We compared the maximum moment magnitude of different scenarios by controlling the same injection volume.The results revealed the effect and advantage of the multi-well scheme in reducing seismic magnitude.To reduce the risk of induced seismicity,utilizing far-fault operational wells to compensate for the effects of near-fault operational wells proves to be an efficient and cost-effective method,with potential for wide practical applications.
文摘A seismic swarm occurred southeast of King George Island,South Shetland Islands,Antarctica,between August 2020 and February 2021.This work intends to parameterize seismic events recorded by seismic station AM.R4DE2 from 15 September to 31 October 2020.Using the localization methodology with a single station,the record of the entire period was analyzed manually to determine the local magnitude,hypocentral distance,epicentral distance,backazimuth,and location of the epicenter for each event.We could parameterize 6362 events,although we estimate the occurrence to be around 20000 for the period.The results suggest a magmatic origin for the swarm,supporting previous studies.Seismicity exhibited a southeastward migration away from King George Island,as indicated by a progressive increase in epicentral distance over time.Most events were classified as volcanic and volcano-tectonic,supporting a magmatogenesis hypothesis linked to the opening of Bransfield Ridge.
基金Derek Elsworth acknowledges the support from a Gledden Visiting Fellowship from the Institute of Advanced Studies at the University of Western Australia,Australia,and the G.Albert Shoemaker Endowment at Pennsylvania State University,USA.
文摘Triggered seismicity is a key hazard where fluids are injected or withdrawn from the subsurface and may impact permeability. Understanding the mechanisms that control fluid injection-triggered seismicity allows its mitigation. Key controls on seismicity are defined in terms of fault and fracture strength, second-order frictional response and stability, and competing fluid-driven mechanisms for arrest. We desire to constrain maximum event magnitudes in triggered earthquakes by relating pre-existing critical stresses to fluid injection volume to explain why some recorded events are significantly larger than anticipated seismic moment thresholds. This formalism is consistent with several uncharacteristically large fluid injection-triggered earthquakes. Such methods of reactivating fractures and faults by hydraulic stimulation in shear or tensile fracturing are routinely used to create permeability in the subsurface. Microearthquakes (MEQs) generated by such stimulations can be used to diagnose permeability evolution. Although high-fidelity data sets are scarce, the EGS-Collab and Utah FORGE hydraulic stimulation field demonstration projects provide high-fidelity data sets that concurrently track permeability evolution and triggered seismicity. Machine learning deciphers the principal features of MEQs and the resulting permeability evolution that best track permeability changes – with transfer learning methods allowing robust predictions across multiple eological settings. Changes in permeability at reactivated fractures in both shear and extensional modes suggest that permeability change (Δk) scales with the seismic moment (M) of individual MEQs as Δk∝M. This scaling relation is exact at early times but degrades with successive MEQs, but provides a method for characterizing crustal permeability evolution using MEQs, alone. Importantly, we quantify for the first time the role of prestress in defining the elevated magnitude and seismic moment of fluid injection-triggered events, and demonstrate that such MEQs can also be used as diagnostic in quantifying permeability evolution in the crust.
基金funded by the National Natural Science Foundation of China(Grant No.51574225)Shandong Energy Group(Grant No.SNKJ2022BJ03-R28)for Caiping Lu+1 种基金the Research Team on MonitoringActivity Mechanisms of Unnatural Earthquakes of Shandong Earthquake Agency(Grant No.TD202301)for Chengyu Liu.
文摘Mining-related seismicity poses significant challenges in underground coal mining due to its complex rupture mechanisms and associated hazards.To bridge gaps in understanding these intricate processes,this study employed a multi-local seismic monitoring network,integrating both in-mine and local instruments at overlapping length scales.We specifically focused on a damaging local magnitude(ML)2.6 event and its aftershocks that occurred on 10 September 2022 in the vicinity of the 3308 working face of the Yangcheng coal mine in Shandong Province,China.Moment tensor(MT)inversion revealed a complex cascading rupture mechanism:an initial moment magnitude(M_(w))2.2 normal fault slip along the DF60 fault in an ESEeWNW direction,transitioning to a M_(w)3.0 event as the FD24 and DF60 faults unclamped.The scale-independent self-similarity and stress heterogeneity of mining-related seismicity were investigated through source parameter calculations,providing valuable insights into the driving mechanism of these seismic sequences.The in-mine network,constrained by its low dynamic changes,captured only the nucleation phase of the DF60 fault.Furthermore,standard decomposition of the MT solution from the seismic network proved inadequate for accurately identifying the complex nature of the rupture.To enhance safety and risk management in mining environments,we examined the implications of source reactivation within the cluster area post-stress-adjustment.This comprehensive multiscale analysis offers crucial insights into the complex rupture mechanisms and hazards associated with mining-related seismicity.The results underscore the importance of continuous multi-local network monitoring and advanced analytical techniques for improved disaster assessment and risk mitigation in mining operations.
文摘This work focuses on enhancing low frequency seismic data using a convolutional neural network trained on synthetic data.Traditional seismic data often lack both high and low frequencies,which are essential for detailed geological interpretation and various geophysical applications.Low frequency data is particularly valuable for reducing wavelet sidelobes and improving full waveform inversion(FWI).Conventional methods for bandwidth extension include seismic deconvolution and sparse inversion,which have limitations in recovering low frequencies.The study explores the potential of the U-net,which has been successful in other geophysical applications such as noise attenuation and seismic resolution enhancement.The novelty in our approach is that we do not rely on computationally expensive finite difference modelling to create training data.Instead,our synthetic training data is created from individual randomly perturbed events with variations in bandwidth,making it more adaptable to different data sets compared to previous deep learning methods.The method was tested on both synthetic and real seismic data,demonstrating effective low frequency reconstruction and sidelobe reduction.With a synthetic full waveform inversion to recover a velocity model and a seismic amplitude inversion to estimate acoustic impedance we demonstrate the validity and benefit of the proposed method.Overall,the study presents a robust approach to seismic bandwidth extension using deep learning,emphasizing the importance of diverse and well-designed but computationally inexpensive synthetic training data.
基金supported in part by the National Key Research and Development Project of China(No.2022YFC3004602)in part by the National Natural Science Foundation of China(Nos.52121003 and 52442406)。
文摘With the advancement of fracturing technologies in deeper and more geologically complex formations,fault reactivation and induced seismicity have attracted increasing attention.The increasing frequency and magnitude of these events underscore the need for a robust understanding of the governing physical mechanisms.Elevated pore pressure,modified fault-loading conditions,and aseismic slip are widely acknowledged as the primary drivers.Recent studies have explored these mechanisms under varying factors,including fluid properties,rock ductility,poroelastic responses,and evolving fault stress states,thereby offering critical insights into model refinement.Probabilistic forecasting approaches,which combine statistical analyses of historical data with real-time monitoring,are being increasingly adopted in seismic risk assessments.In parallel,machine learning techniques are employed to process large seismic datasets and identify key patterns.However,their predictive capabilities remain limited by geological heterogeneity,subsurface complexity,and scarce observational data.Moreover,fluid–rock interactions further complicate the development of universally applicable models,thereby constraining the generalizability of mitigation strategies.This review synthesizes the current understanding of induced seismicity mechanisms,evaluates the prevailing prediction and mitigation methods,and identifies major challenges and future research directions.Advancements in these areas are essential to enhancing seismic risk management and ensuring the safe,sustainable development of deep-subsurface energy resources.
基金funded by the National Natural Science Foundation of China(No.42174104No.U1939204:No.42204089)+2 种基金the Hubei Provincial Natural Science Foundation of China(2022CFB350)Fund of Wuhan,Gravitation and Solid Earth Tides,National Observation and Research Station(WHYWZ202108WHYWZ202301)。
文摘To analyze the triggering relationship of historical earthquakes to the 2023 Jishishan earthquake and estimate the seismic risk in the adjacent region after the earthquake,we calculate the evolution process of seismic stress generated by 11 earthquakes with MS≥6.0 and 1 earthquake with MS5.7 near the source in the past 100 years.The results show that before the 2023 Jishishan earthquake,the entire Lajishan Northern Edge Fault zone was under the stress shadow generated by the 12 earthquakes.The stress reduction at the 2023 Jishishan earthquake epicenter was approximately 15.1 kPa,and the contribution of this stress shadow mainly comes from the 1920 MS8.5 Haiyuan earthquake.The coseismic stress drop at the epicenter was around-292.1 kPa,and the maximum stress drop for the 2023 Jishishan earthquake was around-346.2 kPa.The Jishishan earthquake increased the stress of the two seismic gaps in the Lajishan Northern Edge Fault by 14.7 kPa and 59.7 k Pa respectively,the stress on the Lajishan Southern Edge Fault zone increased by 10.9 kPa,and the stress on the east section of Xunhua Nanshan Fault increased by 11.1 kPa.These stress increments potentially elevate the seismic hazard along these fault zones.In the future earthquake prevention and disaster reduction,attention should be paid to the seismic risk of these fault zones.
