Geomorphology and Natural Hazards

Tim Davies is Professor in the School of Earth and Environment at University of Canterbury, New Zealand. Educated in Civil Engineering in UK in the 1970s, he taught in Agricultural Engineering and subsequently Natural Resources Engineering at Lincoln University, New Zealand before transferring to University of Canterbury in the present millennium to teach into Engineering Geology and Disaster Risk and Resilience. He has published a total of over 140 papers on a range of pure and applied geomorphology topics including river mechanics and management, debris-flow hazards and management, landslides, earthquakes and fault mechanics, rock mechanics and alluvial fans; natural hazard and disaster risk and resilience.Oliver Korup is Professor in the Institute of Environmental Sciences and Geography and the Institute of Geosciences, University of Potsdam, Germany. Following an academic training in Germany and New Zealand, his research and teaching is now at the interface between geomorphology, natural hazards, and data science. He has worked on catastrophic erosion and disturbances in mountain belts, particularly on landslides, natural dams, river-channel changes, and glacial lake outburst floods.John J. Clague is Emeritus Professor at Simon Fraser University. He was educated at Occidental College, the University of California Berkeley, and the University of British Columbia. He worked as a Research Scientist with the Geological Survey of Canada from 1975 until 1998, and in Department of Earth Sciences at Simon Fraser University from 1998 until 2016. Clague is a Quaternary geologist with research specializations in glacial geology, geomorphology, natural hazards, and climate change, and has authored over 200 papers on these topics. He is a Fellow of the Royal Society of Canada and an Officer of the Order of Canada.

• Preface xiAcknowledgements xv1 Natural Disasters and Sustainable Development in Dynamic Landscapes 11.1 Breaking News 11.2 Dealing with Future Disasters: Potentials and Problems 51.3 The Sustainable Society 101.4 Benefits from Natural Disasters 121.5 Summary 16References 162 Defining Natural Hazards, Risks, and Disasters 192.1 Hazard Is Tied To Assets 192.1.1 Frequency and Magnitude 202.1.2 Hazard Cascades 242.2 Defining and Measuring Disaster 252.3 Trends in Natural Disasters 262.4 Hazard is Part of Risk 272.4.1 Vulnerability 282.4.2 Elements at Risk 322.4.3 Risk Aversion 352.4.4 Risk is a Multidisciplinary Expectation of Loss 362.5 Risk Management and the Risk Cycle 372.6 Uncertainties and Reality Check 392.7 A Future of More Extreme Events? 412.8 Read More About Natural Hazards and Disasters 43References 463 Natural Hazards and Disasters Through the Geomorphic Lens 493.1 Drivers of Earth Surface Processes 503.1.1 Gravity, Solids, and Fluids 503.1.2 Motion Mainly Driven by Gravity 523.1.3 Motion Mainly Driven by Water 543.1.4 Motion Mainly Driven by Ice 563.1.5 Motion Driven Mainly by Air 563.2 Natural Hazards and Geomorphic Concepts 573.2.1 Landscapes are Open, Nonlinear Systems 573.2.2 Landscapes Adjust to Maximize Sediment Transport 593.2.3 Tectonically Active Landscapes Approach a Dynamic Equilibrium 623.2.4 Landforms Develop Toward Asymptotes 653.2.5 Landforms Record Recent Most Effective Events 683.2.6 Disturbances Travel Through Landscapes 693.2.7 Scaling Relationships Inform Natural Hazards 71References 734 Geomorphology Informs Natural Hazard Assessment 774.1 Geomorphology Can Reduce Impacts from Natural Disasters 774.2 Aims of Applied Geomorphology 804.3 The Geomorphic Footprints of Natural Disasters 814.4 Examples of Hazard Cascades 864.4.1 Megathrust Earthquakes, Cascadia Subduction Zone 864.4.2 Postseismic River Aggradation, Southwest New Zealand 904.4.3 Explosive Eruptions and their Geomorphic Aftermath, Southern Volcanic Zone, Chile 934.4.4 Hotter Droughts Promote Less Stable Landscapes, Western United States 93References 945 Tools for Predicting Natural Hazards 975.1 The Art of Prediction 975.2 Types of Models for Prediction 1005.3 Empirical Models 1025.3.1 Linking Landforms and Processes 1025.3.2 Regression Models 1075.3.3 Classification Models 1095.4 Probabilistic Models 1115.4.1 Probability Expresses Uncertainty 1115.4.2 Probability Is More than Frequency 1155.4.3 Extreme-value Statistics 1195.4.4 Stochastic Processes 1215.4.5 Hazard Cascades, Event Trees, and Network Models 1225.5 Prediction and Model Selection 1245.6 Deterministic Models 1265.6.1 Static Stability Models 1265.6.2 Dynamic Models 127References 1376 Earthquake Hazards 1456.1 Frequency and Magnitude of Earthquakes 1456.2 Geomorphic Impacts of Earthquakes 1486.2.1 The Seismic Hazard Cascade 1486.2.2 Postseismic and Interseismic Impacts 1526.3 Geomorphic Tools for Reconstructing Past Earthquakes 1546.3.1 Offset Landforms 1556.3.2 Fault Trenching 1586.3.3 Coseismic Deposits 1616.3.4 Buildings and Trees 166References 1677 Volcanic Hazards 1737.1 Frequency and Magnitude of Volcanic Eruptions 1737.2 Geomorphic Impacts of Volcanic Eruptions 1777.2.1 The Volcanic Hazard Cascade 1777.2.2 Geomorphic Impacts During Eruption 1777.2.3 Impacts on the Atmosphere 1807.2.4 Geomorphic Impacts Following an Eruption 1817.3 Geomorphic Tools for Reconstructing Past Volcanic Impacts 1887.3.1 Effusive Eruptions 1887.3.2 Explosive Eruptions 1917.4 Climate-Driven Changes in Crustal Loads 195References 1978 Landslides and Slope Instability 2038.1 Frequency and Magnitude of Landslides 2038.2 Geomorphic Impacts of Landslides 2108.2.1 Landslides in the Hazard Cascade 2108.2.2 Landslides on Glaciers 2128.2.3 Submarine Landslides 2138.3 Geomorphic Tools for Reconstructing Landslides 2138.3.1 Landslide Inventories 2138.3.2 Reconstructing Slope Failures 2158.4 Other Forms of Slope Instability: Soil Erosion and Land Subsidence 2188.5 Climate Change and Landslides 220References 2259 Tsunami Hazards 2339.1 Frequency and Magnitude of Tsunamis 2339.2 Geomorphic Impacts of Tsunamis 2369.2.1 Tsunamis in the Hazard Cascade 2369.2.2 The Role of Coastal Geomorphology 2379.3 Geomorphic Tools for Reconstructing Past Tsunamis 2419.4 Future Tsunami Hazards 252References 25310 Storm Hazards 25710.1 Frequency and Magnitude of Storms 25710.1.1 Tropical Storms 25710.1.2 Extratropical Storms 25910.2 Geomorphic Impacts of Storms 26110.2.1 The Coastal Storm-Hazards Cascade 26110.2.2 The Inland Storm-Hazard Cascade 26610.3 Geomorphic Tools for Reconstructing Past Storms 26910.3.1 Coastal Settings 27010.3.2 Inland Settings 27310.4 Naturally Oscillating Climate and Increasing Storminess 275References 28011 Flood Hazards 28511.1 Frequency and Magnitude of Floods 28611.2 Geomorphic Impacts of Floods 28911.2.1 Floods in the Hazard Cascade 28911.2.2 Natural Dam-break Floods 29111.2.3 Channel Avulsion 29711.3 Geomorphic Tools for Reconstructing Past Floods 29811.4 Lessons from Prehistoric Megafloods 30611.5 Measures of Catchment Denudation 30811.6 The Future of Flood Hazards 311References 31512 Drought Hazards 32312.1 Frequency and Magnitude of Droughts 32312.1.1 Defining Drought 32412.1.2 Measuring Drought 32512.2 Geomorphic Impacts of Droughts 32612.2.1 Droughts in the Hazard Cascade 32612.2.2 Soil Erosion, Dust Storms, and Dune Building 32712.2.3 Surface Runoff and Rivers 33212.3 Geomorphic Tools for Reconstructing Past Drought Impacts 33412.4 Towards More Megadroughts? 339References 34213 Wildfire Hazards 34513.1 Frequency and Magnitude of Wildfires 34513.2 Geomorphic Impacts of Wildfires 34813.2.1 Wildfires in the Hazard Cascade 34813.2.2 Direct Fire Impacts 34813.2.3 Indirect and Postfire Impacts 35013.3 Geomorphic Tools for Reconstructing Past Wildfires 35413.4 Towards More Megafires? 359References 36114 Snow and Ice Hazards 36514.1 Frequency and Magnitude of Snow and Ice Hazards 36514.2 Geomorphic Impact of Snow and Ice Hazards 36714.2.1 Snow and Ice in the Hazard Cascade 36714.2.2 Snow and Ice Avalanches 36714.2.3 Jökulhlaups 37414.2.4 Degrading Permafrost 37514.2.5 Other Ice Hazards 37914.3 Geomorphic Tools for Reconstructing Past Snow and Ice Processes 38014.4 Atmospheric Warming and Cryospheric Hazards 384References 38915 Sea-Level Change and Coastal Hazards 39515.1 Frequency and Magnitude of Sea-Level Change 39915.2 Geomorphic Impacts of Sea-Level Change 40415.2.1 Sea Levels in the Hazard Cascade 40415.2.2 Sedimentary Coasts 40415.2.3 Rocky Coasts 40715.3 Geomorphic Tools for Reconstructing Past Sea Levels 40815.4 A Future of Rising Sea Levels 411References 41416 How Natural are Natural Hazards? 41916.1 Enter the Anthropocene 41916.2 Agriculture, Geomorphology, and Natural Hazards 42416.3 Engineered Rivers 43016.4 Engineered Coasts 43516.5 Anthropogenic Sediments 43816.6 The Urban Turn 44316.7 Infrastructure’s Impacts on Landscapes 44516.8 Humans and Atmospheric Warming 44616.9 How Natural Are Natural Hazards and Disasters? 448References 45017 Feedbacks with the Biosphere 45717.1 The Carbon Footprint of Natural Disasters 45717.1.1 Erosion and Intermittent Burial 46017.1.2 Organic Carbon in River Catchments 46617.1.3 Climatic Disturbances 46917.2 Protective Functions 47317.2.1 Forest Ecosystems 47317.2.2 Coastal Ecosystems 478References 48518 The Scope of Geomorphology in Dealing with Natural Risks and Disasters 49518.1 Motivation 49618.2 The Geomorphologist’s Role 49818.3 The Disaster Risk Management Process 49918.3.1 Identify Stakeholders 50018.3.2 Know and Share Responsibilities 50118.3.3 Understand that Risk Changes 50318.3.4 Analyse Risk 50418.3.5 Communicate and Deal with Risk Aversion 50518.3.6 Evaluate Risks 50718.3.7 Share Decision Making 50918.4 The Future – Beyond Risk? 51118.4.1 Limitations of the Risk Approach 51118.4.2 Local and Regional Disaster Impact Reduction 51118.4.3 Relocation of Assets 51318.4.4 A Way Forward? 514References 51619 Geomorphology as a Tool for Predicting and Reducing Impacts from Natural Disasters 51919.1 Natural Disasters Have Immediate and Protracted Geomorphic Consequences 51919.2 Natural Disasters Motivate Predictive Geomorphology 52019.3 Natural Disasters Disturb Sediment Fluxes 52119.4 Geomorphology of Anthropocenic Disasters 521References 523Glossary 525Index 531