Anthony Adwan, Bertrand Maillot, Pauline Souloumiac, Christophe Barnes, Christophe Nussbaum, Meinert Rahn, Thomas Van Stiphout
{"title":"利用通用地质力学模型和聚类方法了解推力褶皱横向终点的应力场","authors":"Anthony Adwan, Bertrand Maillot, Pauline Souloumiac, Christophe Barnes, Christophe Nussbaum, Meinert Rahn, Thomas Van Stiphout","doi":"10.5194/egusphere-2024-1906","DOIUrl":null,"url":null,"abstract":"<strong>Abstract.</strong> <span>This study employs numerical simulations based on the Limit Analysis (LA) method to calculate the stress distribution in a </span><span>kilometric</span><span>-scale model developed over a basal detachment, featuring the lateral termination of a generic fault under compression. We conduct 2500 </span><span>2D</span><span> and 500 </span><span>3D</span><span> simulations, varying basement and fault friction angles, to analyze and classify the results into clusters representing similar failure patterns to understand the stress fields. Automatic fault detection methods are employed to identify the number and positions of fault lines in </span><span>2D</span><span> and fault surfaces in </span><span>3D</span><span>. Clustering approaches are utilized to group the models based on the detected failure patterns. For the </span><span>2D</span><span> models, the analysis reveals three primary clusters and five transitional ones, qualitatively consistent with the critical Coulomb wedge theory and the influence of inherited structural and geometric aspects over rupture localization. In the </span><span>3D</span><span> models, four different clusters portray the lateral prolongation of the inherited fault. High stress magnitudes are detected between the </span><span>compressive</span><span> boundary and the activated or created faults, and at the root of the inherited active fault. Tension zones appear near the outcropping surface relief while stress decreases with depth at the </span><span>footwall</span><span> of the created back-thrusts. A statistical, cluster-based stress field analysis indicates that for a given cluster, the stress field mainly conserves the same orientations, while the magnitude varies with changes in friction angles and </span><span>compressive</span><span> field intensity, except in failure zones where variations are sparse. Small parametric variations could lead to significantly different stress fields, while larger deviations might result in similar configurations. The comparison between </span><span>2D</span><span> and </span><span>3D</span><span> models shows the importance of lateral stresses and their influence on rupture patterns, distinguishing between </span><span>3D</span><span> analysis and </span><span>2D</span><span> cross-sections. Lastly, despite using small-scale models, stress field variations over a span of a couple of kilometers are quite large.</span>","PeriodicalId":21912,"journal":{"name":"Solid Earth","volume":"22 1","pages":""},"PeriodicalIF":3.2000,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Understanding the stress field at the lateral termination of a thrust fold using generic geomechanical models and clustering methods\",\"authors\":\"Anthony Adwan, Bertrand Maillot, Pauline Souloumiac, Christophe Barnes, Christophe Nussbaum, Meinert Rahn, Thomas Van Stiphout\",\"doi\":\"10.5194/egusphere-2024-1906\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<strong>Abstract.</strong> <span>This study employs numerical simulations based on the Limit Analysis (LA) method to calculate the stress distribution in a </span><span>kilometric</span><span>-scale model developed over a basal detachment, featuring the lateral termination of a generic fault under compression. We conduct 2500 </span><span>2D</span><span> and 500 </span><span>3D</span><span> simulations, varying basement and fault friction angles, to analyze and classify the results into clusters representing similar failure patterns to understand the stress fields. Automatic fault detection methods are employed to identify the number and positions of fault lines in </span><span>2D</span><span> and fault surfaces in </span><span>3D</span><span>. Clustering approaches are utilized to group the models based on the detected failure patterns. For the </span><span>2D</span><span> models, the analysis reveals three primary clusters and five transitional ones, qualitatively consistent with the critical Coulomb wedge theory and the influence of inherited structural and geometric aspects over rupture localization. In the </span><span>3D</span><span> models, four different clusters portray the lateral prolongation of the inherited fault. High stress magnitudes are detected between the </span><span>compressive</span><span> boundary and the activated or created faults, and at the root of the inherited active fault. Tension zones appear near the outcropping surface relief while stress decreases with depth at the </span><span>footwall</span><span> of the created back-thrusts. A statistical, cluster-based stress field analysis indicates that for a given cluster, the stress field mainly conserves the same orientations, while the magnitude varies with changes in friction angles and </span><span>compressive</span><span> field intensity, except in failure zones where variations are sparse. Small parametric variations could lead to significantly different stress fields, while larger deviations might result in similar configurations. The comparison between </span><span>2D</span><span> and </span><span>3D</span><span> models shows the importance of lateral stresses and their influence on rupture patterns, distinguishing between </span><span>3D</span><span> analysis and </span><span>2D</span><span> cross-sections. Lastly, despite using small-scale models, stress field variations over a span of a couple of kilometers are quite large.</span>\",\"PeriodicalId\":21912,\"journal\":{\"name\":\"Solid Earth\",\"volume\":\"22 1\",\"pages\":\"\"},\"PeriodicalIF\":3.2000,\"publicationDate\":\"2024-07-03\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Solid Earth\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://doi.org/10.5194/egusphere-2024-1906\",\"RegionNum\":2,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"GEOCHEMISTRY & GEOPHYSICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Solid Earth","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.5194/egusphere-2024-1906","RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"GEOCHEMISTRY & GEOPHYSICS","Score":null,"Total":0}
Understanding the stress field at the lateral termination of a thrust fold using generic geomechanical models and clustering methods
Abstract.This study employs numerical simulations based on the Limit Analysis (LA) method to calculate the stress distribution in a kilometric-scale model developed over a basal detachment, featuring the lateral termination of a generic fault under compression. We conduct 2500 2D and 500 3D simulations, varying basement and fault friction angles, to analyze and classify the results into clusters representing similar failure patterns to understand the stress fields. Automatic fault detection methods are employed to identify the number and positions of fault lines in 2D and fault surfaces in 3D. Clustering approaches are utilized to group the models based on the detected failure patterns. For the 2D models, the analysis reveals three primary clusters and five transitional ones, qualitatively consistent with the critical Coulomb wedge theory and the influence of inherited structural and geometric aspects over rupture localization. In the 3D models, four different clusters portray the lateral prolongation of the inherited fault. High stress magnitudes are detected between the compressive boundary and the activated or created faults, and at the root of the inherited active fault. Tension zones appear near the outcropping surface relief while stress decreases with depth at the footwall of the created back-thrusts. A statistical, cluster-based stress field analysis indicates that for a given cluster, the stress field mainly conserves the same orientations, while the magnitude varies with changes in friction angles and compressive field intensity, except in failure zones where variations are sparse. Small parametric variations could lead to significantly different stress fields, while larger deviations might result in similar configurations. The comparison between 2D and 3D models shows the importance of lateral stresses and their influence on rupture patterns, distinguishing between 3D analysis and 2D cross-sections. Lastly, despite using small-scale models, stress field variations over a span of a couple of kilometers are quite large.
期刊介绍:
Solid Earth (SE) is a not-for-profit journal that publishes multidisciplinary research on the composition, structure, dynamics of the Earth from the surface to the deep interior at all spatial and temporal scales. The journal invites contributions encompassing observational, experimental, and theoretical investigations in the form of short communications, research articles, method articles, review articles, and discussion and commentaries on all aspects of the solid Earth (for details see manuscript types). Being interdisciplinary in scope, SE covers the following disciplines:
geochemistry, mineralogy, petrology, volcanology;
geodesy and gravity;
geodynamics: numerical and analogue modeling of geoprocesses;
geoelectrics and electromagnetics;
geomagnetism;
geomorphology, morphotectonics, and paleoseismology;
rock physics;
seismics and seismology;
critical zone science (Earth''s permeable near-surface layer);
stratigraphy, sedimentology, and palaeontology;
rock deformation, structural geology, and tectonics.