Preprints
https://doi.org/10.5194/egusphere-2024-1906
https://doi.org/10.5194/egusphere-2024-1906
03 Jul 2024
 | 03 Jul 2024
Status: this preprint is open for discussion.

Understanding the stress field at the lateral termination of a thrust fold using generic geomechanical models and clustering methods

Anthony Adwan, Bertrand Maillot, Pauline Souloumiac, Christophe Barnes, Christophe Nussbaum, Meinert Rahn, and Thomas Van Stiphout

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.

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this preprint. The responsibility to include appropriate place names lies with the authors.
Anthony Adwan, Bertrand Maillot, Pauline Souloumiac, Christophe Barnes, Christophe Nussbaum, Meinert Rahn, and Thomas Van Stiphout

Status: open (until 28 Aug 2024)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2024-1906', Anonymous Referee #1, 23 Jul 2024 reply
Anthony Adwan, Bertrand Maillot, Pauline Souloumiac, Christophe Barnes, Christophe Nussbaum, Meinert Rahn, and Thomas Van Stiphout
Anthony Adwan, Bertrand Maillot, Pauline Souloumiac, Christophe Barnes, Christophe Nussbaum, Meinert Rahn, and Thomas Van Stiphout

Viewed

Total article views: 114 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
80 28 6 114 22 5 5
  • HTML: 80
  • PDF: 28
  • XML: 6
  • Total: 114
  • Supplement: 22
  • BibTeX: 5
  • EndNote: 5
Views and downloads (calculated since 03 Jul 2024)
Cumulative views and downloads (calculated since 03 Jul 2024)

Viewed (geographical distribution)

Total article views: 111 (including HTML, PDF, and XML) Thereof 111 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 24 Jul 2024
Download
Short summary
We use computer simulations to study how stress is distributed in large-scale geological models, focusing on how fault lines behave under pressure. By running many 2D and 3D simulations with varying conditions, we discover patterns in how faults form and interact. Our findings reveal that even small changes in conditions can lead to different stress outcomes. This research helps us better understand earthquake mechanics and could improve predictions of fault behavior in real-world scenarios.