Titre :	High-Resolution Aftershock-Based Imaging of Active Faults, Source Parameters and Earthquake Driving Mechanisms: A Contribution to Seismic Hazard Assessment in Northeastern Algeria
Type de document :	document électronique
Auteurs :	El-Mahdi Tikhamarine, Auteur ; Issam Abacha, Directeur de thèse
Editeur :	Sétif:UFA1
Année de publication :	2025
Importance :	1 vol (321 f.)
Format :	29 cm
Langues :	Anglais (eng)
Catégories :	Thèses & Mémoires:Physique
Mots-clés :	High precision relocation Aftershocks-based imaging Focal mechanism analysis Moment tensor analysis Earthquake mutiplet.
Index. décimale :	530 - Physique
Résumé :	Seismology has experienced significant advancements since its establishment in the mid-20th century, driven by the increasing need to comprehend and mitigate the impacts of earthquakes. Earthquakes, often sudden and violent, have long been a source of fear and terror due to their devastating effects on both infrastructure and human lives. As the understanding of plate tectonics and seismic activity evolved, modern seismology emerged as a powerful tool to investigate the underlying causes of these natural phenomena. The present thesis, titled "High-Resolution Aftershock-Based Imaging of Active Faults, Source Parameters, and Earthquake Driving Mechanisms: A Contribution to Seismic Hazard Assessment in Northeastern Algeria" builds upon these developments. The main aim is to contribute valuable insights to the assessment of seismic hazards in the northeastern region of Algeria. The thesis is structured around three core components. First, it focuses on high-resolution aftershock-based imaging, providing detailed depictions of fault systems to improve the understanding of fault geometries and potential earthquake nucleation zones. Utilizing advanced techniques such as double-difference relocation and hierarchical clustering of earthquake multiplet, this work identifies previously unmapped fault segments. Second, it involves the analysis of earthquake source parameters, including seismic moment, fault geometry, stress drop, and source radius. These parameters provide crucial insights into earthquake mechanics and the characteristics of faults in the study area. Third, the research investigates earthquake driving mechanisms, including tectonic loading, stress transfer, fluid intrusion, and aseismic slip, to unravel the complex factors contributing to earthquake occurrence in this tectonically active region. Our research began with a detailed analysis of the Beni-Ilmane sequence 2010, serving as a foundation for generalizing our methodology to seismic sequences that occurred between 2007 and 2022 across northeastern Algeria. By analyzing seismic sequences from 2007 to 2022, this research compiles a comprehensive database of active faults, seismic parameters, and earthquake mechanisms. The Findings serves as a critical resource for evaluating seismic hazard and developing risk mitigation strategies. This work highlights the importance of integrating seismic data, fault imaging, and earthquake modeling to enhance the resilience of infrastructures in northeastern Algeria against future seismic events.
Note de contenu :	Sommaire Chapter I Faults Kinematics and Earthquakes Nucleation I.1 Introduction ...........................................................................................................................11 I.2 What Is a Fault? .................................................................................................................... 12 I.2.1 Complex Fault Model .................................................................................................. 13 I.2.2 Simplistic Fault Model ................................................................................................ 17 I.3 Focal Mechanism And Fault Motion ............................................................................... 19 I.3.1 First Motion Polarities ................................................................................................. 20 I.3.2 More Constraints Through Temporal or Spectral Amplitude Information ..... 23 I.3.3 Moment Tensor ............................................................................................................. 25 a) Important Notions .................................................................................................. 25 b) MT Inversion ........................................................................................................... 32 I.4 Stress Tensor and Faulting Mechanisms ........................................................................ 34 I.5 Do Earthquakes Always Initiate New Ruptures? ......................................................... 36 I.6 Seismic Fracture Dynamics ............................................................................................... 38 I.6.1 Fracture Expansion Modes.......................................................................................... 38 I.6.2 The Cohesive Zone ........................................................................................................... 39 I.6.3 Frictional Laws .................................................................................................................. 41 a) Stick-Slip Friction Model (Static/Dynamic Model) ............................................. 41 b) Slip-Weakening Friction Model .............................................................................. 42 c) Rate-And-State Friction Model ................................................................................... 44 I.7 Nucleation And Arrest Process Of Earthquake Rupture ............................................. 45 I.7.1 Nucleation Process ....................................................................................................... 45 I.7.3 Fault Plane Complexities, Barriers And Asperities ............................................... 46 a) Barriers model ......................................................................................................... 47 b) Asperities Model..................................................................................................... 47 c) Barrier-Asperity Duality ....................................................................................... 49 I.8 Earthquakes Interactions ................................................................................................... 49 I.8.1 Foreshocks..................................................................................................................... 50 I.8.2 Aftershocks .................................................................................................................... 51 I.8.3 Swarms ........................................................................................................................... 55 I.9 Clusters of Earthquakes With Similar Waveform ........................................................ 55 I.9.1 Earthquake Multiplet .................................................................................................. 56 I.9.2 Repeating Earthquakes ............................................................................................... 60 I.9.3 Ambiguities In Definitions: Distinguishing Multiplets And Repeating Earthquakes ............................................................................................................................ 63 I.9.4 Our Used Terminology................................................................................................ 64 I.10 Conclusion ...................................................................................................................... 64 Chapter II New Seismotectonic Model for Beni-Ilmane Region II.1 Introduction ........................................................................................................................ 66 II.1.1 Geological Framework Of Beni-Ilmane Region ................................................... 66 II.1.2 Indicators Of Fluid Accumulation........................................................................... 68 II.1.3 Review Of Scientific Literature On The BI-2010 Sequence ............................... 70 II.2 New Minimum 1D Velocity Model For BI Region, And Absolute Locations ....... 72 II.3 High Precision Relocation ................................................................................................ 80 II.3.1 Hypodd Relocation ..................................................................................................... 81 a) Time Domain Cross-Correlation (CC) ...................................................................... 82 b) Frequency Domain Coherency (Coh) ....................................................................... 85 c) Cross-Correlation V.S Coherency .............................................................................. 87 II.3.2 Growclust Relocation ................................................................................................. 91 II.3.3 Why Use Both Hypodd and Growclust? ................................................................ 92 II.3.4 Results of BI-2010 Seismicty Relocation ................................................................ 93 II.4 Moment Tensor Analysis for The Three Mainshocks ................................................ 95 II.5 Focal Mechanism Analysis............................................................................................... 97 II.6 Multiplet Analysis: Deciphering Complex Fault Structures in BI region ............ 101 II.7: Conceptual Model: Highlighting the Critical Role of Strike-Slip Faults .............112 II.8 Conclusion.........................................................................................................................115 Chapter III Dynamic Source Parameters' Analysis III.1 Introduction ......................................................................................................................117 III.2 Near and Far Field Displacement .................................................................................118 III.2.1 Near-Field displacement .........................................................................................118 III.2.2 Far-Field Displacement ...........................................................................................119 III.2.3 Limit Between the two fields ................................................................................ 120 III.3 Source Models Commonly Utilized ........................................................................... 121 III.3.1 Haskell’s Rectangular Source Model .................................................................. 121 III.3.2 Brune’s Circular Source Model............................................................................. 123 III.3.3 Why Preferring Brune’s Model Over Haskell’s ................................................ 124 III.4 The Individual Spectra Approach for Source Parameters Estimation ................. 125 III.5 Seismic moment and source time function ............................................................... 132 III.6 The Empirical Green’s Function (EGF) Approach for Source Parameters Estimation ................................................................................................................................ 138 III.7 Scaling relationships ..................................................................................................... 142 III.8 Application on BI-2010 seismic sequence ................................................................. 143 III.8.1 EGF Candidates' Selection .................................................................................... 144 III.8.2 Source Parameters Estimation (Results) ............................................................. 146 a) Individual Spectra Approach ................................................................................... 147 b) EGF Approach ............................................................................................................. 152 III.9 Results Analysis ............................................................................................................. 158 III.9.1 Does Self-Similarity Really Break Down in Beni-Ilmane? ............................ 158 III.9.2 Mw-ML Scaling Relationship for Beni-Ilmane Region .................................. 160 III.9.3 Comparison of EGF and Individual Spectra Source Parameters ................... 161 III.9.4 Scaling Relationships from Our Results (M0-R and M0-fc) ............................. 163 III.10 Conclusion ..................................................................................................................... 166 Chapter IV Mechanisms Driving the BI-2010 Sequence: An Analysis IV.1 Introduction ..................................................................................................................... 167 IV.2 Tectonic Loading in BI Region .................................................................................... 168 IV.3 Can Stress Transfer Alone Explain the Observed Seismicity In The BI-2010 Sequence? ................................................................................................................................ 172 IV.4 Extra Evidences of Fluid Involvement ....................................................................... 175 IV.4.1 Evidence from Moment tensor decomposition ................................................. 176 a) Polarity constrained by amplitude information ................................................... 178 b) Full-waveform inversion .......................................................................................... 180 c) Results Discussion ...................................................................................................... 184 IV.4.2 Evidence from Stress Drop Variation.................................................................. 185 IV.5 Insights into Fluid Processes from the Temporal Evolution of Multiplets ........ 189 IV.6 Seismicity Migration Analysis: Insights into Aseismic Afterslip ........................ 192 IV.7 Repeating Earthquakes: Additional Evidence of Aseismic Slip ........................... 195 IV.7.1 Detection of Repeating Earthquakes ................................................................... 195 IV.7.2 Explanation for Repeating Earthquakes in the BI-2010 Sequence ................ 199 IV.8 What Mechanism Drove the BI-2010 Sequence? A Summary ............................... 200 IV.9 Probable Hydromechanical Interpretation of the BI-2010 Sequence ................... 200 IV.10 Conclusion ..................................................................................................................... 201 Chapter V Geometric and Physical Characterization of Active Faults in Northeastern Algeria V.1 Introduction ...................................................................................................................... 203 V.2 Algeria’s Seismic Hazard Framework.......................................................................... 203 V.2.1 Seismotectonic Features........................................................................................... 203 V.2.2 Seismic Hazards Features ........................................................................................ 206 a) The Most Significant Earthquakes .................................................................... 206 b) The Maximum Observed Intensity (MOI2014) ................................................. 206 c) The Peak Ground Acceleration .......................................................................... 207 d) Seismic zoning of Algeria ................................................................................... 210 V.3 Recent Earthquake Activity in Northeastern Algeria ............................................... 212 .....
Côte titre :	Dph/0315

High-Resolution Aftershock-Based Imaging of Active Faults, Source Parameters and Earthquake Driving Mechanisms: A Contribution to Seismic Hazard Assessment in Northeastern Algeria [document électronique] / El-Mahdi Tikhamarine, Auteur ; Issam Abacha, Directeur de thèse . - [S.l.] : Sétif:UFA1, 2025 . - 1 vol (321 f.) ; 29 cm.
Langues : Anglais (eng)

Catégories :	Thèses & Mémoires:Physique
Mots-clés :	High precision relocation Aftershocks-based imaging Focal mechanism analysis Moment tensor analysis Earthquake mutiplet.
Index. décimale :	530 - Physique
Résumé :	Seismology has experienced significant advancements since its establishment in the mid-20th century, driven by the increasing need to comprehend and mitigate the impacts of earthquakes. Earthquakes, often sudden and violent, have long been a source of fear and terror due to their devastating effects on both infrastructure and human lives. As the understanding of plate tectonics and seismic activity evolved, modern seismology emerged as a powerful tool to investigate the underlying causes of these natural phenomena. The present thesis, titled "High-Resolution Aftershock-Based Imaging of Active Faults, Source Parameters, and Earthquake Driving Mechanisms: A Contribution to Seismic Hazard Assessment in Northeastern Algeria" builds upon these developments. The main aim is to contribute valuable insights to the assessment of seismic hazards in the northeastern region of Algeria. The thesis is structured around three core components. First, it focuses on high-resolution aftershock-based imaging, providing detailed depictions of fault systems to improve the understanding of fault geometries and potential earthquake nucleation zones. Utilizing advanced techniques such as double-difference relocation and hierarchical clustering of earthquake multiplet, this work identifies previously unmapped fault segments. Second, it involves the analysis of earthquake source parameters, including seismic moment, fault geometry, stress drop, and source radius. These parameters provide crucial insights into earthquake mechanics and the characteristics of faults in the study area. Third, the research investigates earthquake driving mechanisms, including tectonic loading, stress transfer, fluid intrusion, and aseismic slip, to unravel the complex factors contributing to earthquake occurrence in this tectonically active region. Our research began with a detailed analysis of the Beni-Ilmane sequence 2010, serving as a foundation for generalizing our methodology to seismic sequences that occurred between 2007 and 2022 across northeastern Algeria. By analyzing seismic sequences from 2007 to 2022, this research compiles a comprehensive database of active faults, seismic parameters, and earthquake mechanisms. The Findings serves as a critical resource for evaluating seismic hazard and developing risk mitigation strategies. This work highlights the importance of integrating seismic data, fault imaging, and earthquake modeling to enhance the resilience of infrastructures in northeastern Algeria against future seismic events.
Note de contenu :	Sommaire Chapter I Faults Kinematics and Earthquakes Nucleation I.1 Introduction ...........................................................................................................................11 I.2 What Is a Fault? .................................................................................................................... 12 I.2.1 Complex Fault Model .................................................................................................. 13 I.2.2 Simplistic Fault Model ................................................................................................ 17 I.3 Focal Mechanism And Fault Motion ............................................................................... 19 I.3.1 First Motion Polarities ................................................................................................. 20 I.3.2 More Constraints Through Temporal or Spectral Amplitude Information ..... 23 I.3.3 Moment Tensor ............................................................................................................. 25 a) Important Notions .................................................................................................. 25 b) MT Inversion ........................................................................................................... 32 I.4 Stress Tensor and Faulting Mechanisms ........................................................................ 34 I.5 Do Earthquakes Always Initiate New Ruptures? ......................................................... 36 I.6 Seismic Fracture Dynamics ............................................................................................... 38 I.6.1 Fracture Expansion Modes.......................................................................................... 38 I.6.2 The Cohesive Zone ........................................................................................................... 39 I.6.3 Frictional Laws .................................................................................................................. 41 a) Stick-Slip Friction Model (Static/Dynamic Model) ............................................. 41 b) Slip-Weakening Friction Model .............................................................................. 42 c) Rate-And-State Friction Model ................................................................................... 44 I.7 Nucleation And Arrest Process Of Earthquake Rupture ............................................. 45 I.7.1 Nucleation Process ....................................................................................................... 45 I.7.3 Fault Plane Complexities, Barriers And Asperities ............................................... 46 a) Barriers model ......................................................................................................... 47 b) Asperities Model..................................................................................................... 47 c) Barrier-Asperity Duality ....................................................................................... 49 I.8 Earthquakes Interactions ................................................................................................... 49 I.8.1 Foreshocks..................................................................................................................... 50 I.8.2 Aftershocks .................................................................................................................... 51 I.8.3 Swarms ........................................................................................................................... 55 I.9 Clusters of Earthquakes With Similar Waveform ........................................................ 55 I.9.1 Earthquake Multiplet .................................................................................................. 56 I.9.2 Repeating Earthquakes ............................................................................................... 60 I.9.3 Ambiguities In Definitions: Distinguishing Multiplets And Repeating Earthquakes ............................................................................................................................ 63 I.9.4 Our Used Terminology................................................................................................ 64 I.10 Conclusion ...................................................................................................................... 64 Chapter II New Seismotectonic Model for Beni-Ilmane Region II.1 Introduction ........................................................................................................................ 66 II.1.1 Geological Framework Of Beni-Ilmane Region ................................................... 66 II.1.2 Indicators Of Fluid Accumulation........................................................................... 68 II.1.3 Review Of Scientific Literature On The BI-2010 Sequence ............................... 70 II.2 New Minimum 1D Velocity Model For BI Region, And Absolute Locations ....... 72 II.3 High Precision Relocation ................................................................................................ 80 II.3.1 Hypodd Relocation ..................................................................................................... 81 a) Time Domain Cross-Correlation (CC) ...................................................................... 82 b) Frequency Domain Coherency (Coh) ....................................................................... 85 c) Cross-Correlation V.S Coherency .............................................................................. 87 II.3.2 Growclust Relocation ................................................................................................. 91 II.3.3 Why Use Both Hypodd and Growclust? ................................................................ 92 II.3.4 Results of BI-2010 Seismicty Relocation ................................................................ 93 II.4 Moment Tensor Analysis for The Three Mainshocks ................................................ 95 II.5 Focal Mechanism Analysis............................................................................................... 97 II.6 Multiplet Analysis: Deciphering Complex Fault Structures in BI region ............ 101 II.7: Conceptual Model: Highlighting the Critical Role of Strike-Slip Faults .............112 II.8 Conclusion.........................................................................................................................115 Chapter III Dynamic Source Parameters' Analysis III.1 Introduction ......................................................................................................................117 III.2 Near and Far Field Displacement .................................................................................118 III.2.1 Near-Field displacement .........................................................................................118 III.2.2 Far-Field Displacement ...........................................................................................119 III.2.3 Limit Between the two fields ................................................................................ 120 III.3 Source Models Commonly Utilized ........................................................................... 121 III.3.1 Haskell’s Rectangular Source Model .................................................................. 121 III.3.2 Brune’s Circular Source Model............................................................................. 123 III.3.3 Why Preferring Brune’s Model Over Haskell’s ................................................ 124 III.4 The Individual Spectra Approach for Source Parameters Estimation ................. 125 III.5 Seismic moment and source time function ............................................................... 132 III.6 The Empirical Green’s Function (EGF) Approach for Source Parameters Estimation ................................................................................................................................ 138 III.7 Scaling relationships ..................................................................................................... 142 III.8 Application on BI-2010 seismic sequence ................................................................. 143 III.8.1 EGF Candidates' Selection .................................................................................... 144 III.8.2 Source Parameters Estimation (Results) ............................................................. 146 a) Individual Spectra Approach ................................................................................... 147 b) EGF Approach ............................................................................................................. 152 III.9 Results Analysis ............................................................................................................. 158 III.9.1 Does Self-Similarity Really Break Down in Beni-Ilmane? ............................ 158 III.9.2 Mw-ML Scaling Relationship for Beni-Ilmane Region .................................. 160 III.9.3 Comparison of EGF and Individual Spectra Source Parameters ................... 161 III.9.4 Scaling Relationships from Our Results (M0-R and M0-fc) ............................. 163 III.10 Conclusion ..................................................................................................................... 166 Chapter IV Mechanisms Driving the BI-2010 Sequence: An Analysis IV.1 Introduction ..................................................................................................................... 167 IV.2 Tectonic Loading in BI Region .................................................................................... 168 IV.3 Can Stress Transfer Alone Explain the Observed Seismicity In The BI-2010 Sequence? ................................................................................................................................ 172 IV.4 Extra Evidences of Fluid Involvement ....................................................................... 175 IV.4.1 Evidence from Moment tensor decomposition ................................................. 176 a) Polarity constrained by amplitude information ................................................... 178 b) Full-waveform inversion .......................................................................................... 180 c) Results Discussion ...................................................................................................... 184 IV.4.2 Evidence from Stress Drop Variation.................................................................. 185 IV.5 Insights into Fluid Processes from the Temporal Evolution of Multiplets ........ 189 IV.6 Seismicity Migration Analysis: Insights into Aseismic Afterslip ........................ 192 IV.7 Repeating Earthquakes: Additional Evidence of Aseismic Slip ........................... 195 IV.7.1 Detection of Repeating Earthquakes ................................................................... 195 IV.7.2 Explanation for Repeating Earthquakes in the BI-2010 Sequence ................ 199 IV.8 What Mechanism Drove the BI-2010 Sequence? A Summary ............................... 200 IV.9 Probable Hydromechanical Interpretation of the BI-2010 Sequence ................... 200 IV.10 Conclusion ..................................................................................................................... 201 Chapter V Geometric and Physical Characterization of Active Faults in Northeastern Algeria V.1 Introduction ...................................................................................................................... 203 V.2 Algeria’s Seismic Hazard Framework.......................................................................... 203 V.2.1 Seismotectonic Features........................................................................................... 203 V.2.2 Seismic Hazards Features ........................................................................................ 206 a) The Most Significant Earthquakes .................................................................... 206 b) The Maximum Observed Intensity (MOI2014) ................................................. 206 c) The Peak Ground Acceleration .......................................................................... 207 d) Seismic zoning of Algeria ................................................................................... 210 V.3 Recent Earthquake Activity in Northeastern Algeria ............................................... 212 .....
Côte titre :	Dph/0315