Paleoseismology (eBook)

Front Cover 1
Paleoseismology 4
Copyright Page 5
Contents 6
Contributors 14
Preface to the Second Edition 16
Chapter 1: Introduction to Paleoseismology 18
1.1. The Scope of Paleoseismology 18
1.1.1. Definition and Objectives 18
1.1.2. Organization and Scope of This Book 22
1.1.3. The Relation of Paleoseismology to Other Neotectonic Studies 22
1.2. Identifying Prehistoric Earthquakes from Primary and Secondary Evidence 25
1.2.1. Classification of Paleoseismic Evidence 25
1.2.2. The Incompleteness of the Paleoseismic Record 32
1.2.3. Underrepresentation Versus Overrepresentation of the Paleoseismic Record 34
1.3. Prehistoric Earthquake Dating and Recurrence 36
1.3.1. Dating Accuracy and Precision and Their Relation to Recurrence 38
1.3.2. Patterns in Recurrence 40
1.4. Estimating the Magnitude of Prehistoric Earthquakes 40
1.5. The Early Development of Paleoseismology, 1890-1980 42
Acknowledgments 44
Chapter 2A: Field Techniques in Paleoseismology-Terrestrial Environments 46
2A.1. Introduction 46
2A.1.1. Scope of the Chapter 46
2A.1.2. Preferred Sequence of Investigations 47
2A.2. Mapping Paleoseismic Landforms 47
2A.2.1. Locating Surface Deformation 47
2A.2.2. Mapping Deposits Versus Landforms in Seismic Areas 59
2A.2.3. Detailed Topographic Mapping 60
2A.2.4. Topographic Profiling 63
2A.2.5. Dating Methods for Late Quaternary Landforms 65
2A.3. Mapping Paleoseismic Stratigraphy 66
2A.3.1. Geophysical Techniques in Paleoseismology 67
2A.3.2. Trenching 78
2A.3.3. Drilling, Coring, Slicing, and Peeling 114
2A.3.4. Dating Methods for Late Quaternary Deposits 120
2A.4. Distinguishing Paleoseismic Features from Nonseismic or•Nontectonic Features 122
2A.4.1. Special Case: Stable Continental Interiors 125
2A.5. Specialized Subfields of Paleoseismology 128
2A.5.1. Archeoseismology 129
2A.5.2. Dendroseismology 134
Chapter 2B: Sub-Aqueous Paleoseismology 136
2B.1. Introduction 136
2B.1.1. Scope of the Chapter 136
2B.2. Mapping and Dating Paleoseismic Landforms Offshore 137
2B.2.1. Submarine Mapping and Imaging Methods 137
2B.2.2. Dating Submarine Structures, Landforms, and Deposits Using Paleoseismic Stratigraphy 143
2B.3. Locating Primary Evidence: Active Faulting and Structures 150
2B.3.1. Direct Fault Investigations 150
2B.3.2. Off-Fault Investigation 158
2B.4. Locating Secondary Evidence: Landslides, Turbidites, Submarine Tsunami Deposits 160
2B.4.1. Distinguishing Earthquake and Nonearthquake Triggering Mechanisms 162
2B.4.2. Turbidite Paleoseismology 168
2B.4.3. Offshore Tsunami Deposits 178
2B.4.4. Lacustrine Environments 180
2B.4.5. Submarine Landslides Triggered by Earthquakes 185
2B.4.6. Coeval Fault Motion and Fluid Venting Evidence 186
Acknowledgments 187
Chapter 3: Paleoseismology in Extensional Tectonic Environments 188
3.1. Introduction 188
3.1.1. Styles, Scales, and Environments of Extensional Deformation 189
3.1.2. The Earthquake Deformation Cycle in Extensional Environments 192
3.1.3. Historic Analog Earthquakes 195
3.2. Geomorphic Evidence of Paleoearthquakes 196
3.2.1. Tectonic Geomorphology of Normal Fault Blocks 198
3.2.2. Features of Bedrock Fault Planes and Other Rock Surfaces 201
3.2.3. Formation of Fault Scarps in Unconsolidated Deposits 203
3.2.4. Degradation of Fault Scarps in Unconsolidated Deposits 216
3.2.5. Spatial and Temporal Variations in Surface Displacement 221
3.2.6. Geomorphic Features Formed by Single and Recurrent Faulting 224
3.3. Stratigraphic Evidence of Paleoearthquakes 233
3.3.1. Characteristics of Near-Surface Normal Faults in Section 234
3.3.2. Distinguishing Tectonic from Depositional Features 238
3.3.3. Sedimentation and Soil Formation in the Fault Zone 243
3.3.4. Measuring Displacement on Normal Fault Exposures 259
3.3.5. Distinguishing Creep Displacement from Episodic Displacement 261
3.4. Dating Paleoearthquakes 262
3.4.1. Direct Dating of the Exposed Fault Plane 262
3.4.2. Direct Dating via Scarp Degradation Modeling 264
3.4.3. Age Estimates from Soil Development on Fault Scarps 268
3.4.4. Bracketing the Age of Faulting by Dating Geomorphic Surfaces 270
3.4.5. Bracketing the Age of Faulting by Dating Displaced Deposits 271
3.4.6. Bracketing the Age of Faulting by Dating Colluvial Wedges 272
3.4.7. Age Estimates from Cosmogenic Nuclides in Depth Profiles on Fault Scarps 276
3.5. Interpreting the Paleoseismic History by Retrodeformation 277
3.5.1. Types of Retrodeformations 278
3.5.2. Assumptions Used when Restoring Strata to their Prefaulting Geometry 278
3.5.3. Accounting for Soil Development in Retrodeformation 281
3.6. Distinguishing Tectonic from Nontectonic Normal Faults 283
3.6.1. Tectonic, but Nonseismogenic Normal Faults 283
3.6.2. Nontectonic, but Seismogenic Normal Faults 284
3.6.3. Nontectonic and Nonseismogenic Normal Faults 284
Chapter 4: Paleoseismology of Volcanic Environments 288
4.1. Introduction 288
4.2. Volcano-Extensional Structures 290
4.2.1. Worldwide Examples of Volcano-Extensional Structures 290
4.2.2. Central Volcanoes and Calderas 295
4.2.3. Volcanic Rift Zones 296
4.2.4. Magma-Induced Slope Instability 306
4.2.1. Worldwide Examples of Volcano-Extensional Structures 290
4.3. Criteria for Field Recognition of Volcano-Extensional Features 307
4.3.1. Results of Empirical and Numerical Modeling 307
4.3.2. Volcano-Tectonic Geomorphology 309
4.3.3. Geophysical Methods 311
4.3.4. Geodetic Remote-Sensing Techniques 311
4.4. Paleoseismological Implications and Methods 312
4.4.1. Excavation 313
4.4.2. Geochronology 315
4.4.3. Recurrence Intervals 315
4.4.4. Maximum Magnitude 316
4.5. Conclusions 329
4.6. Information on the Companion Web site 331
Acknowledgments 331
Chapter 5: Paleoseismology of Compressional Tectonic Environments 332
5.1. Introduction 332
5.1.1. Organization of This Chapter 333
5.1.2. Styles, Scales, and Environments of Deformation 333
5.1.3. The Earthquake Deformation Cycle of Reverse Faults 339
5.1.4. Historic Analog Earthquakes 340
5.2. Geomorphic Evidence of Reverse Paleoearthquakes 344
5.2.1. Initial Morphology of Reverse and Thrust Fault Scarps 345
5.2.2. Degradation of Thrust Fault Scarps 346
5.2.3. Interaction of Thrust Fault Scarps with Geomorphic Surfaces 347
5.2.4. Slip Rate Studies 351
5.2.5. Spatial and Temporal Variations in Surface Displacement 351
5.3. Stratigraphic Evidence of Reverse and Thrust Paleoearthquakes 354
5.3.1. General Style of Deformation on Reverse Faults in Section 355
5.3.2. Trenching Techniques 357
5.3.3. Structure and Evolution of Reverse-Fault Scarps 359
5.3.4. Structure and Evolution of Thrust Fault Scarps 363
5.3.5. Stratigraphic Bracketed Offset 367
5.3.6. Fault-Onlap Sedimentary Sequences 368
5.3.7. Summary of Stratigraphic Evidence for Thrust Paleoearthquakes 369
5.3.8. Distinguishing Creep Displacement from Episodic Displacement 369
5.4. Dating Paleoearthquakes 371
5.4.1. Direct Dating of the Exposed Fault Plane 371
5.4.2. Direct Dating via Scarp Degradation Modeling 371
5.4.3. Age Estimates from Soil Development on Fault Scarps 373
5.4.4. Bracketing the Age of Faulting by Dating Displaced Deposits 373
5.5. Interpreting the Paleoseismic History by Retrodeformation 375
5.5.1. Rigid-Block Retrodeformations 375
5.5.2. Plastic Retrodeformations 375
5.6. Distinguishing Seismogenic from Nonseismogenic Reverse Faults 378
5.6.1. Tectonic, but Nonseismogenic Reverse Faults 378
5.6.2. Nontectonic, but Seismogenic Reverse Faults 382
5.6.3. Nontectonic and Nonseismogenic Reverse Faults 382
5.7. Hazards Due to Reverse Surface Faulting 383
5.8. Paleoseismic Evidence of Coseismic Folding 385
5.8.1. Geomorphic Evidence of Active Surface Folding 385
5.8.2. Stratigraphic Evidence of Active Surface Folding 388
5.8.3. Assessing Seismic Hazards from Blind Thrusts 392
5.9. Paleoseismology of Subduction Zones 396
5.9.1. Introduction 396
5.9.2. Segmentation of Subduction Zones 399
5.9.3. Surface Faulting: Upper Plate Versus Plate-Boundary Structures 400
5.9.4. Historic Subduction Earthquakes as Modern Analogs for Paleoearthquakes 402
5.9.5. The Earthquake Deformation Cycle in Subduction Zones 405
5.10. Late Quaternary Sea Level 407
5.10.1. Sea-Level Index Points along Erosional Shorelines 409
5.10.2. Sea-Level Index Points Along Depositional Shorelines 410
5.11. The Coseismic Earthquake Horizon 412
5.11.1. Characteristics of Coseismic Earthquake Horizons 412
5.11.2. Earthquake-Killed Trees 415
5.11.3. Tsunami Deposits 415
5.11.5. Summary of Stratigraphic Evidence for Paleoseismicity 419
5.12. Paleoseismic Evidence of Coseismic Uplift 420
5.12.1. Alaska 421
5.12.2. Cascadia Subduction Zone 423
5.13. Paleoseismic Evidence of Coseismic Subsidence 428
5.13.1. Alaska 428
5.13.2. Cascadia Subduction Zone 432
5.13.3. Ambiguities in Characterizing Subduction Paleoearthquakes 436
Chapter 6: Paleoseismology of Strike-Slip Tectonic Environments 438
6.1. Introduction 438
6.1.1. Styles, Scales, and Environments of Deformation 439
6.1.2. Segmentation of Strike-Slip Faults 444
6.1.3. The Earthquake Deformation Cycle of Strike-Slip Faults 444
6.1.4. Historic Analog Earthquakes 445
6.2. Geomorphic Evidence of Paleoearthquakes 449
6.2.1. Landforms Used as Piercing Points 450
6.2.2. Using Lateral Offsets to Calculate Long-Term Slip Rates 469
6.2.3. Spatial and Temporal Variations in Surface Displacement 473
6.2.4. Reconstructing Individual Earthquake Displacements 476
6.3. Stratigraphic Evidence of Paleoearthquakes 479
6.3.1. General Style of Deformation on Strike-Slip Faults in Section 480
6.3.2. Sedimentation and Weathering in Strike-Slip Fault Zones 481
6.3.3. Trenching Techniques 485
6.3.4. Stratigraphic Indicators of Paleoearthquakes 490
6.3.5. Measuring Lateral Displacements from Stratigraphic Data 496
6.3.6. Distinguishing Creep Displacement from Episodic Displacement 506
6.4. Dating Paleoearthquakes 506
6.5. Interpreting the Paleoseismic History by Retrodeformation 508
6.5.1. Retrodeforming the Trench Log 510
6.6. Distinguishing Seismogenic from Nonseismogenic Strike-Slip Faults 512
6.6.1. Tectonic, But Nonseismogenic Strike-Slip Faults 512
6.6.2. Nontectonic and Nonseismogenic Strike-Slip Faults 513
Chapter 7: Using Liquefaction-Induced and Other Soft-Sediment Features for Paleoseismic Analysis 514
7.1. Introduction 514
7.2. Overview of the Formation of Liquefaction-Induced Features 516
7.2.1. Process of Liquefaction and Fluidization 520
7.2.2. Factors Affecting Liquefaction Susceptibility and Effects of Fluidization 522
7.3. Criteria for an Earthquake-Induced Liquefaction Origin 526
7.4. Historic and Prehistoric Liquefaction-Selected Studies 527
7.4.1. Coastal South Carolina 527
7.4.2. New Madrid Seismic Zone 535
7.4.3. Wabash Valley Seismic Zone 552
7.4.4. Coastal Washington State 557
7.5. Features Generally of Nonseismic or Unknown Origin 563
7.5.1. Terrestrial Disturbance Features 564
7.5.2. Features Formed in Subaqueous Environments 565
7.5.3. Features Formed by Weathering 573
7.5.4. Features Formed in a Periglacial Environment 574
7.6. Estimation of Strength of Paleoearthquakes 575
7.6.1. Association with Modified Mercalli Intensity 575
7.6.2. Magnitude Bound 575
7.6.3. Engineering-Based Procedures 577
7.6.4. Overview of Estimates of Magnitude 580
7.6.5. Negative Evidence 581
Chapter 8: Using Landslides for Paleoseismic Analysis 582
8.1. Introduction 582
8.2. Identifying Landslides 583
8.3. Determining Landslide Ages 585
8.3.1. Historical Methods 585
8.3.2. Dendrochronology 585
8.3.3. Radiometric and Cosmogenic Dating 586
8.3.4. Lichenometry 587
8.3.5. Weathering Rinds 587
8.3.6. Pollen Analysis 587
8.3.7. Geomorphic Analysis 587
8.4. Interpreting an Earthquake Origin for Landslides 588
8.4.1. Regional Analysis of Landslides 588
8.4.2. Landslide Morphology 591
8.4.3. Sackungen 592
8.4.4. Sediment from Earthquake-Triggered Landslides 594
8.4.5. Landslides That Straddle Fault 595
8.4.6. Precariously Balanced Rocks 595
8.4.7. Speleoseismology 596
8.4.8. Summary 597
8.5. Analysis of the Seismic Origin of a Landslide 597
8.5.1. Physical Setting of Landslides in the New Madrid Seismic Zone 598
8.5.2. Geotechnical Investigation 598
8.5.3. Static (Aseismic) Slope-Stability Analysis 600
8.5.4. Dynamic (Seismic) Slope-Stability Analysis 601
8.5.5. Analysis of Unknown Seismic Conditions 612
8.6. Interpreting Results of Paleoseismic Landslide Studies 613
8.6.1. Characteristics of Landslides Triggered by Earthquakes 613
8.6.2. Interpreting Earthquake Magnitude and Location 616
8.7. Final Comments 617
Subject Index 620
International Geophysics Series 632
Color Plates 636
Chapter 9: Application of Paleoseismic Data to Seismic Hazard Assessment and Neotectonic Research 671
9.1. Introduction 671
9.1.1. Seismic Hazard Assessments: A Brief Description 673
9.2. Estimating Paleoearthquake Magnitude 675
9.2.1. Methods Using Primary Evidence 676
9.2.2. Methods Using Secondary Evidence 692
9.3. Paleoseismic Slip Rates and Recurrence 692
9.3.1. Constructing Slip History Diagrams: Temporal Variations in Displacement at a Point 693
9.3.2. Slip Rates 696
9.3.3. Slip-Along-Strike Diagrams: Displaying Both Spatial and Temporal Variations in Displacement Along Strike 702
9.3.4. Recurrence Estimation Using Slip Rates 706
9.3.5. Recurrence Estimation Using Numerical Dating of Paleoearthquakes 707
9.3.6. Constructing Space-Time Diagrams 710
9.3.7. Interpreting Space-Time Diagrams for Contemporaneity of Paleoearthquakes and Multisegment Ruptures 713
9.4. Fault Segmentation 714
9.4.1. Earthquake Segments 717
9.4.2. Fault Segments 717
9.4.3. Segment Boundaries 719
9.4.4. Behavior of Segment Boundaries 719
9.4.5. Segmentation of Historic Surface Ruptures 721
9.4.6. Is the Segmentation Concept Useful? 721
9.5. Models of Fault Behavior 724
9.5.1. Variable Slip Models 725
9.5.2. Uniform Slip Models 727
9.6. Models of Earthquake Recurrence 728
9.6.1. Statistical Analysis of Paleoearthquake Chronologies 730
9.6.2. Temporal Clustering, Fault ''Contagion," and Causative Mechanisms for Irregular Recurrence 736
9.6.3. Using Recurrence Data to Estimate Conditional Probability of Future Rupture 740
9.7. Use of Paleoseismic Data in Deterministic and Probabilistic Seismic Hazard Analyses 742
9.7.1. Deterministic SHAs 742
9.7.2. Probabilistic SHAs as National Seismic Hazard Maps 745
9.7.3. Probabilistic SHAs for Sites and Regions: The Art of Logic Trees 746
9.7.4. Probabilistic Fault Displacement Hazard 761
9.8. Site Studies for Surface Rupture 762
9.8.1. Determine Whether Quaternary Faults Exist at a Site 764
9.8.2. Accurately Identify and Locate the Faults 764
9.8.3. Determine the Age of Most Recent Surface Rupture and Activity Class of the Faults 767
9.8.4. Using Paleoseismic Data on Displacement for Recommending Fault Setback Distances 770
9.9. Paleoseismic Data Applied to Neotectonic Research 772
9.10. Current Issues and Future Prospects in Paleoseismology 773
9.10.1. Recognizing Paleoearthquakes 773
9.10.2. Estimating Displacement/Magnitude 774
9.10.3. Estimating Age/Recurrence 775
9.10.4. Testing Fault Models 775
9.10.5. Scientific Policy 776
Appendix 1: Earthquake Magnitude Scales 777
A.1.1. Local (Richter) Magnitude (ML) 777
A.1.2. Surface-Wave Magnitude (MS) 778
A.1.3. Body-Wave Magnitude (MbLg) 778
A.1.4. Moment Magnitude (MW OR M) 779
Appendix 2: Radiocarbon Sampling Techniques 781
A.2.1. How much to Sample 781
A.2.2. Sample Pretreatment 781
Appendix 3: Field Evaluation of Liquefaction Susceptibility of Soils with High Fines Content 783
References 785
Color Plates 636