Fault-Zone Properties arid Earthquake Rupture Dynamics Eiichi Fukuyama National Research Institute for Earth Science,and Disaster Prevention Tsukuba, Japan i ':-> i' ' -':'.." \,' " '' L VH ELSEVIER AMSTERDAM BOSTON HEIDELBERG LONDON NEW YORK-OXFORD-PARIS-SAN DIEGO SAN FRANCISCO SINGAPORE SYDNEY TOKYO Academic Press is an imprint of Elsevier
Contents Preface.. xi Foreword xiii List of Contributors, xv 1. Introduction: Fault-Zone Properties and Earthquake Rupture Dynamics. 1 Eiichi Fukuyama 2. Geometry and Slip Distribution of Coseismic Surface Ruptures Produced by the 2001 Kunlun, Northern Tibet, Earthquake 15 Aiming Lin 1. Introduction. 16 2. Tectonic Setting ' 18 3. Deformation Characteristics of the 2001 Coseismic Surface Rupture 19 3.1, Geometric Distribution and Deformational Structure 19 3.2. Coseismic Slip Distribution 24 3.2.1. Measurement Method of Strike-Slip Offset ' 24 3.2.2. Field Observations 26 3.2.3. Analysis of High-Resolution Remote Sensing Images 28 3.2.4. Seismic Inversion Results 29 4. Discussion, 30 4.1. Relationship between the Coseismic Surface Rupture and Preexisting Fault 30 4.2. Coseismic Strike-Slip Displacement 31 5. Conclusions " 33 3. Aseismic-Seismic Transition and Fluid Regime along Subduction Plate Boundaries and a Fossil Example from the Northern Apennines of Italy 37 Paola Vannucchi, Francesca Remitti, Jason Phipps-Morgan and Giuseppe Bettelli 1. Introduction " 3 8 2. Deformation and Seismogenesis at Accretionary and Erosive Subduction Margins 40 3. Seismogenic Zone^ Definition, 4 2 4. Slow Slip Events and Seismic Tremors 46 5. Seismically Produced Structures - 48
i) Contents 6. The Up-Dip Limit of Seismogenesis in a Fossil Erosive Subduction Channel ' 52 6.1. Subduction Channel Architecture 53 6.2. Subduction Channel Internal Structure: A Low-Friction Plate Boundary 55 7. Discussion and Comparison between Erosive and Accretionary Seismogenic Zones, " -'58-8. Conclusions and Future Perspective 59 4 Fault Zone Structure and Deformation Processes along an Exhumed Low-Angle Normal Fault: Implications for Seismic Behavior 69 Cristiano Collettini, Robert E. Holdsworth and Steven A. F. Smith 1. Introduction f. 7 0. 2. Regional Setting.,. ' / 71 3. Fault Zone Architecture..' j- 73 3.1. Geometry and kinematics c. 73 3.2. Fault Rock Distribution and Microstructures - 75 4. Discussion ' ' 78 4.1. Fault Rock Evolution 78 4.2'. The Mechanical Paradox of Low-Angle Normal Faults 79 4.3. A Slip Model for Low-Angle Normal Faults (Evidences That ZF Was Active as LAN F) 80 5. Conclusions " 82 5 Pseudotachylytes and Earthquake Source Mechanics 87 Giulio Di Toro, Giorgio Pennacchioni and Stefan Nielsen 1. Introduction. 87 2. Pseudotachylytes. 8 9 2.1. Mesoscale Geometry of Pseudotachylyte 90 2.2. Microstructures and Geochemistry in Pseudotachylytes 91 2.3. Temperature Estimate of Frictional Melts 93 2.4. Distribution of Tectonic Pseudotachylytes 94 2.5. Production of Pseudotachylytes ~.. 95 2.5.1. The Role of Water 99 3. A Natural Laboratory of an Exhumed Seismogenic Source 100 4. Rupture Dynamics -.. '.. 104 4.-1. Transient Stress Pattern 104 4.2. Examples of Transient Stress Markers Observed 105 5. Dynamic Fault Strength '. - 110 5.1. Field Estimates, r 111 " 5.2. Experimental Results >...'. 113 5.3. Theoretical Estimates ' 116 6". Discussions and Conclusions 120 6.1. A New Approach to the Study of Exhumed Pseudotachylyte-Bearing Faults 123
Contents. ( vii ) 6. The Critical Slip Distance for Seismic and Aseismic Fault Zones of Finite Width 135, Chris Marone, Massimo Cocco, Eliza Richardson and Elisa Tinti 1 1. Introduction 136 2. Friction Laws and the Transition from Static to Kinetic Friction 139 3. Contact.Model for the Critical Slip Distance of Solid Surfaces and Shear Zones 140 4. Model for a Shear Zone of Finite Thickness 143 5. Results 146 6.-Implications for Scaling of the Dynamic Slip Weakening Distance 151 h 7. Discussion 154 7. Scaling of Slip Weakening Distance with Final Slip *' during Dynamic Earthquake Rupture 163 Massimo Cocco, Elisa Tinti, Chris Marone and Alessio Piatanesi "' ' 1. Introduction 164 2. Rupture History from Kinematic Source Models 167 3. Inferring Traction Evolution f69 4. Measuring D c 'from Peak Slip Velocity 172 5. Measuring D c from Inferred Traction Evolution Curves 174 6. Scaling between D c and Final Slip 179 7. Discussion and Concluding Remarks 180 8. Rupture Dynamics on Bimaterial Faults and Nonlinear Off-Fault Damage ' N 187 Teruo Yamashita 1. Introduction. 187 2. Formation of Damage Zone due to Dynamic Fault Growth 191. 2.1. Inference about Orientation and Distribution of.secondary Fractures ' 191 2.2. Modeling of Generation of Tensile Microfractures 193 2.3. Modeling of Dynamic Generation of Mesoscopic Shear Branches 195 2.4. Effects of Damage on Earthquake Rupture in a Poroelastic Medium 196 2.5. Rheology of Damage Zone, 197 3. Fault Growth on a Bimaterial Interface 199 3.1. Field Observation of Faults 199 3.2. Quasi-Static Features of In-Plane Tensile Crack 199 3.3. Theoretical and Numerical Studies of Dynamic Fault Slip 199 3.4. Regularization of an Ill-Posed Problem 205 3.5. Poroelastic Bimaterial Effects on Fault Slip - 206
Contents - 3.6; How Much Are Earthquake Ruptures Influenced by Bimaterial Effects? 207 3.7: Macroscopic Parameter Affected by the Existence of Fault at Bimaterial Interface, 209 4. Concluding Remarks 209 9. Boundary integral Equation Method for Earthquake Rupture Dynamics / 217 Taku Tada 1. Introduction 217 2. Basic Equations. 218 2.1. General Description 218, 2.2. Planar Fault of Two-Dimensional Nature 221 2.3. Three-and Two-DimensiohaL Green's Functions 223 2.4. Planar Fault of Three-Dimensionaf Nature. - 225 3. RegularizatioVi. ' ^ 226 3.1. Hypersingularities in the Integration Kernels 226 3.2. Planar Two-Dimensional Antiplane Fault 227 3.3. Planar Three-Dimensional Fault 228 3.4. Planar Two-Dimensional In-Plane Fault! - 231 3.5. Isolating the Instantaneous Response Term 232 -r 4. Spatiotemporal Discretization. 233 4.1. Boundary Elements and Time Steps 233 4.2. Discretizing the Equations 234 4.3. Implicit Time-Marching Scheme 237 4.4. Courant-Friedrichs-Lewy Condition and the Explicit Time-Marching Scheme 237 5. Evaluating Discrete Integration Kernels 239 5.1. Planar Two-Dimensional Antiplane Fault 239 5.2. Planar Two-Dimensional In-Plane Fault 243 5.3. Planar Three-Dimensional Fault 245 5.4. Interface with the Two-Dimensional Theory 247 6. Dealing with Nonplanar Faults 248 6.1. Overview 248 6.2. Evaluating Discrete Integration Kernels 250 6.3. Inventory of Available Stress Response Functions 252 6.3.1. Linear Fault Element in a Two r Dimensional Medium^ 252 6.3.2. Rectangular Fault Element in a Three-Dimensional. Medium. 253' 6.3.3. Triangular Fault Element in a Three-Dimensional Medium 254 6.4. Numerical Modeling Studies in the Literature 254 7. Numerical-Stability 255 8. Related Topics 256 8.1. Fracture Criterion, 256 8.2. Formulation in the Fourier and Laplace Domains.. 257
Contents ' ( fa 8.3. Displacement Discontinuity BIEM 258 8.4. Fault Opening 258 8.5. Faults in a Half-Space 260 8.6. Galerkin Method 262 9. Conclusion. 263 10. Dynamjc Rupture Propagation of the 1995 Kobe, Japan, Earthquake ' 269 Eiichi Fukuyama 1. Introduction - : 269 ^2. Computation Method 272 3. Fault Model ' 273 4. Computation Results 275 5. Discussion and Conclusion. 277 List of Abbreviations 285 Index 289