Geological records of tsunamis and other extreme waves

Cover
Geological Records of Tsunamis and Other Extreme Waves
Copyright
Contents
Contributors
About the Editors
Preface
Section 1 Introduction
1. Geological records of tsunamis and other extreme waves: concepts, applications and a short history of research
Introduction
Disciplinary background
A short history of paleotsunami research
Scope of the book
Outline of the book
Concluding remarks
References
2. Historical records: their importance in understanding and mitigating tsunamis
Introduction
Catalogues and databases
Historical records: importance and limitation
References
3. Tsunami magnitude scales
Introduction
Tsunami magnitude scales: an overview
Relation between tsunami magnitude and intensity
Possibilities and limitations of tsunami magnitude scales
Applicability of tsunami magnitude, Mt, to the case of October 25, 2018, earthquake
Discussion and conclusions
References
4. Trigger mechanisms and hydrodynamics of tsunamis
Trigger mechanisms
Earthquakes
Landslides
Volcanism
Impacts
Complex trigger
Hydrodynamics
Propagation of tsunamis
Wave deformation in shallow waters (shoaling)
Inundation and runup
Backwash
References
5. Tsunami databases
Introduction
Definition
Database development
Problems
Challenges to creating a global tsunami database
Paleotsunami data
Structure
Definition
Validity
Other attributes
Opportunities
References
6. Onshore archives of tsunami deposits
Introduction
Onshore archives of tsunami deposits
Low-lying coastal plains
Marshes and estuaries
Swales within beach-ridge plains
Lagoons
Coastal lakes
Coastal sediment sections
Beaches (back-beach environments)
Caves
Summary
References
Section 2 Field Methods
7. Geophysical prospection and sedimentological characteristics of subaquatic tsunami deposits
Introduction
Why do we need research on offshore tsunami deposits?
Methods to detect offshore tsunami deposits
Sidescan sonar
Multibeam echosounder
Reflection seismic
LiDAR measurements
Sampling of offshore tsunami deposits
Diagnostic criteria of offshore tsunami deposits
Distribution of offshore tsunami deposits: case studies from different regions
Conclusions
References
8. Ground-penetrating radar (GPR) in coastal hazard studies
Introduction
The GPR technique
Theory of GPR and its application in coastal environments
Data collection and processing
Recent advancements
Types of surveys
Processing
GPR use in studying past storms and tsunamis
Erosional records
Other research areas of methodology development
Thin-bed studies
Use of amplitude variation with offset (AVO)
Multiconfiguration surveys
Attribute analysis
3D modeling of GPR data
Conclusions
References
9. Mapping of subaerial coarse clasts
Introduction
Aerial and satellite imagery
Single-point to multi-point measurements
Photogrammetry and Structure-from-Motion
Laser scanning
Point-cloud analysis
Summary
References
10. Post-event field surveys
Introduction and aims
Overview of how to approach the development, deployment and activity of a post-event field survey
Before the survey
During the survey
After the survey
Summary reflections on the tasks/issues associated with organizing and undertaking a post-event field survey
On the evolving “tool kit” of methods available to support post-event field surveys, including those from the broader geolo ...
Reflections on the tensions and challenges a post-event field survey team leader might encounter
Meeting my own and other's expectations
Time
Dealing with the unexpected
Difficult emotions
Conclusions
References
Section 3 Fine-grained Deposits
11. The sedimentology and geometry of fine-grained tsunami deposits from onshore environments
Introduction
Methods
Fine-grained onshore tsunami deposits
Depositional features
Horizontal trends
Grain-size distribution
Stratification
Accumulation of components
Vertical structures
Asymmetrical structures that indicate flow direction
Soft-sediment deformation
Erosional features
Discussion
Conclusions
References
12. Foraminifera in tsunami deposits
Characteristics of coastal foraminifera
Field methods
Modern foraminifera sampling
Tsunami and paleotsunami foraminifera sampling
Laboratory methods
Sample preparation and foraminiferal analysis
Foraminifera taxonomy
Foraminifera test size
Foraminifera taphonomy
Statistical techniques
Example application of foraminifera to tsunami studies
Current challenges
Summary of foraminifera use in tsunami research
References
13. Ostracoda in extreme-wave deposits
Introduction
Who are the Ostracoda?
Taxonomy
Distribution
Preservation and taphonomy
Methods
Field-based methods
Baseline ostracod fauna and ecologies
Deposit sampling
Lab-based methods
Post-laboratory methods
Distinguishing between overwash mechanisms
Conclusions
References
14. Diatoms in tsunami deposits
Introduction: physical and ecological characteristics of diatoms
Diatoms in tsunami deposits
Allochthonous diatoms in tsunami deposits, indicators for sediment provenance
Diatoms as indicators of tsunami runup extent
Sorting of diatom valves in tsunami deposits
Preservation of diatom valves in tsunami deposits
Comparison of diatoms in tsunami and storm-surge deposits
Recommendations for investigating a candidate tsunami deposit
Field work and data collection
Laboratory processing and analyses
Appendix 1: common diatoms reported in tsunami deposits
Appendix 2: published criteria for identifying tsunami deposits using diatoms
Appendix 3: diatom slide preparation and counting
Appendix 4: assessment of diatom preservation
References
15. The application of molluscs for investigating tsunami deposits
Introduction
The use of molluscs in paleotsunami research
Characteristics of mollusc species assemblages in tsunami deposits
Paleo-current flow direction
Infaunality as a proxy for erosion depth
Shell size
Taphonomic processes
Shell material
Taphonomic characteristics
Differences between coastal and offshore settings
Geochemical analysis
Differentiating between tsunami and storm deposits
Conclusions
References
16. Magnetic susceptibility and anisotropy of magnetic susceptibility: versatile tools to decipher hydrodynamic characteristics ...
Introduction
The principles of the anisotropy of magnetic susceptibility
Magnetic susceptibility of tsunami deposits
Anisotropy of magnetic susceptibility
Methodology
Sediment sampling in the field
Caution and limits
Sediment sampling in the laboratory
Field experiments
Laboratory measurements
Contribution of MS/AMS to deciphering tsunami deposits
Environmental magnetism of tsunami deposits
Magnetic signatures of tsunami deposits
Limitations and perspectives
Contribution of AMS to reconstruct the hydrodynamic conditions for the 2004 Indian Ocean Tsunami flooding at Banda Aceh, Su ...
Limitations of the method
Conclusions
References
17. X-ray tomography applied to tsunami deposits
Principles of X-ray tomography
Application to tsunami deposits
Sampling strategy
Image analysis
X-ray anatomy of tsunami deposits
Internal structure of the deposit and bedforms
Soft and fine-grained fraction: soil and mud
Vertical trends of grain size
Sedimentary fabric
Distribution of heavy minerals
Distribution of marine bioclasts
Conclusions
References
18. Applications of geochemical proxies in paleotsunami research
Introduction
Methods
Field sampling
Analytical methods
Examples and significance of geochemical proxies
Onshore deposits
Marine indicators (shell hash, marine carbonate, also seawater)
Indicators of source material (proxy for mineral composition)
Grain-size indicator (Zr/K, Rb and K, Si/(K+Ti))
Seawater influence and post-diagenetic formation of pyrite (TC, TS, Fe and S)
Indicator of source material (terrestrial vs. marine/beach) and geochronological marker
Stable isotopes and C/N
Biomarkers/organic compounds
DNA
Offshore deposits
Current challenges and potentialities
Conclusions
References
19. Microtextures in tsunami deposits: a useful sediment fingerprinting tool
Introduction
Methodology
Laboratory procedure
Microtextural semi-quantitative classification
Shape analysis
Automated microtextural classification
Case studies
Boca do Rio (Portugal)
Arauco and Mataquito (Chile)
Conclusions
References
20. Paleogenetic approaches in tsunami deposit studies
Background
Pioneering metabarcoding applications in paleotsunami research
Protocols for sampling and analysis
Sediment sampling and storage
Establishment of databases and significance of reference material
DNA extraction procedures
Polymerase chain reaction (PCR) and development of specific PCR primers
High-throughput sequencing techniques and post-sequencing analyses
Conclusions
References
21. Post-depositional changes to tsunami deposits and their preservation potential
Introduction
Data sources and methods
Sediment supply and accommodation space
Post-depositional changes in extent and thickness of tsunami deposits
Post-depositional changes in sediment grain size
Post-depositional changes of sedimentary structures and relief
Modifications of tsunami deposits' mineral and chemical composition
Formation of new sedimentary features
Preservation potential over longer timescales
New methods to assess post-depositional changes
Conclusions
References
22. Erosional signatures and reorganization in ridge-and-swale sequences
Introduction
Modifications to ridge-and-swale morphologies by tsunamis and other extreme waves
Erosional scarps and reorientation of beach ridges
Breaches of beach ridges and washover-fan formation
Vertical accretion of sandy ridges during storms
Beach-ridge formation in response to seismically induced land-level changes
Rebuilding of shorelines after catastrophic events and effects on sediment supply
Methods to date and detect imprints of tsunamis and storms in ridge-and-swale morphologies
Concluding remarks
References
23. Experimental and numerical models of fine sediment transport by tsunamis
Introduction
Field surveys and sample analysis methods
Inverse modeling approaches
Particle settling
Particle trajectory
Equilibrium suspension
Combined
Experimental studies
Current challenges, potentialities and future directions
Conclusions
References
Section 4 Coarse-clast Deposits
24. Spatial patterns of subaerial coarse clasts
Introduction
Formation, identification and classification of coarse clasts
Megaclasts: the largest clasts moved by waves
Singular and clustered coastal boulders
Occurrence and definition
Boulder fields with scattered boulders
Storm or tsunami boulders?
Boulder ridges
Coral-rubble ridges and ramparts
Other coarse-clast deposits
Summary
References
25. Mega-tsunami deposits related to ocean island flank collapses and asteroid impacts
Mega-tsunamis generated by ocean island flank collapses
Mega-tsunamis generated by asteroid impacts
Characteristics of mega-tsunami deposits
Conclusions
References
26. Erosive impact of tsunami and storm waves on rocky coasts and post-depositional weathering of coarse-clast deposits
Introduction
Erosive impact of tsunamis on rocky coasts
Cliff destruction: episodic versus long-term effects
Mechanisms of cliff retreat: the significance of lithology, gravity and marine forcing
Intensities of cliff development and recession
Archaeological hints for coastal and cliff-retreat rates
Rates of rock weathering and dissolution
Relative age estimation for boulder transport
Vegetation, lichen cover and microbialites
Rock pools and other bioerosive indicators
Long-term modification of coastal boulders
Conclusions
References
27. Experimental models of coarse-clast transport by tsunamis
Introduction
Dimensionless quantities and scaling of experiments
Dimensional analysis
The Froude number and scaling laws
The Reynolds number
Measuring approaches in the wave tank
Types of wave generation
Parameters studied in physical experiments
Published wave-tank experiments on tsunami-boulder transport
Experimental setups
Key findings
Further related studies
Link to numerical models
Conclusions and recommendations
References
28. Reconstruction of transport modes and flow parameters from coastal boulders
Introduction
Inverse models of boulder transport
Inverse models based on Nott's equation
Inverse models for boulders distributed on cliff tops
Problems remaining in the context of inverse models
Forward models of boulder transport
Differentiation of boulder origin considering hydraulic forces of tsunami and storm waves
Numerical models useful for coastal boulder research
Implications and future perspectives
Conclusions
References
29. Perspective of incipient motion formulas: boulder transport by high-energy waves
Introduction
Modeling boulder transport: theory in retrospect
Threshold entrainment (incipient motion or initiation of motion)
Nott's formulas (Nott, 2003)
Reassessment of Nott's formulas
Correction to lift force
Erroneous use of fundamental physics
Computational drawback
Improvement to Nott's formulas
Revised Nott's formulas and its sensitivity
Submerged/subaerial/joint-bounded boulders with transport mode of sliding, rolling, and saltation (lifting)
Effect of density
Effect of density
Effect of parametric coefficients
Effect of parametric coefficients
Effect of boulder size
Effect of boulder size
Effect of bed slope
Effect of bed slope
Cliff-edge boulders with transport mode of sliding and rolling
Effect of density
Effect of density
Effect of parametric coefficients
Effect of parametric coefficients
Effect of boulder size
Effect of boulder size
Flow depth from incipient motion formulas
Can incipient motion formulas predict flow characteristics at boulder location?
Future of incipient motion formulas
References
Section 5 Dating
30. Radiocarbon dating of tsunami and storm deposits
Introduction
Brief background on methodological aspects of radiocarbon dating and calibration
Dating principles for fine-grained tsunami and storm deposits: different materials and stratigraphic contexts
Basic sampling approaches
In-growth-position samples
Detrital samples
Sampling approach with specific application to core or slab samples
Modeling approaches
Field examples of radiocarbon dating of tsunami deposits
Summary
References
31. Radiocarbon and U/Th dating of tsunami- and storm-transported coarse clasts
Introduction
Principles and methodology of radiocarbon and U/Th dating
Radiocarbon dating
U/Th dating
Challenges when dating tsunami and storm boulders
Suggestions for appropriate sample selection
Suggestions for dating selected samples
Case studies
Conclusions: potential and limitations of tsunami and storm boulder dating with radiocarbon and U/Th
References
32. Optically stimulated luminescence dating of tsunami and storm deposits
Introduction
Outline of OSL burial dating
Challenges for OSL dating of tsunami and storm deposits
Problematic quartz and feldspar OSL properties
Spatially and temporally complex radiation fields in nearshore environments
Incomplete OSL signal resetting
Successful applications of OSL burial dating to tsunami and storm deposits
OSL rock surface dating of tsunami and storm boulders
Conclusions and future prospects
References
33. Archaeological dating of tsunami and storm deposits
Introduction
Dating archaeology
Tsunami and storm horizons dated through association with archaeological sites
Palaikastro, Crete
Caesarea, Israel
Cascadia subduction zone
Conclusion and outlook
References
34. Tephrostratigraphy and tephrochronology
Introduction
Tephra identification and correlation
Applications and challenges: examples from the northwest Pacific
Using tephra to analyze historical events
Using tephra to reconstruct ancient shoreline positions and paleotsunami size
Beach-ridge ages and paleo-shoreline positions
Extrapolating the upper boundary of a modern active beach to the paleo-record: horizontal and vertical changes
Using tephra for calculating tsunami deposit frequency and size-frequency relationships
Conclusions and future perspectives
References
35. Cosmogenic nuclide dating of coarse clasts
Introduction
Cosmogenic nuclides and surface exposure dating: a brief overview
Surface exposure dating of supralittoral coarse clasts: where are we?
Several limitations
Assessing inheritance: importance of pinpointing the source area and targeting overturned clasts
Dealing with post-depositional weathering/erosion of supralittoral clasts
Applying 36Cl exposure dating to corals: a problematic lithology
Several recommendations
3He exposure dating of the Fogo Island flank collapse and resulting megatsunami
Future perspectives
References
36. Paleomagnetic dating of wave-emplaced boulders
Introduction
VRM dating principle
Theoretical background
Sample collection
Laboratory procedures
Application of VRM dating to wave-emplaced boulders
Coral tsunami boulders on Ishigaki Island
Volcanic coastal boulders from Beppu Bay
Metamorphic coastal boulders at the Sanriku coast
Conclusions and overview
References
Subject Index
Event Index
Geographic Index