Landslide Risk Assessment

Contents

Preface and acknowledgements vii

Scientific notation X

Chapter 1 Background to landslide risk assessment 1

Introduction, 1

Risk, 2

Hazard and vulnerability, 4

From hazard to risk, 8

Risk and uncertainty, 11

Risk assessment, 11

Landslide risk assessment, 29

Uncertainty and risk assessment, 32

Risk assessment as a decision-making tool, 36

Structure of the book, 37

Chapter 2 Landslide hazard 39

Introduction, 39

Landslide mechanisms and type, 41

Landslide behaviour, 44

Potential for landsliding, 51

Nature of landslide hazards, 53

Acquiring information: landslide investigation, 68

Landslide susceptibility and hazard assessment, 78

Hazard models, 101

Uncertainty, assurance and defensibility, 124

Comparing the risks associated with different management options, 334

Individual Risk, 346

Societal Risk, 356

Statistics are signs from God? 364

Chapter 7 From risk estimation to landslide management strategy 368

Introduction to landslide risk management, 368

Assessment criteria, 373

Acceptable or tolerable risks, 375

Economic risks, 381

Loss of life, 386

Environmental risk, 390

Environmental acceptance criteria, 395

Climate change uncertainty: implications for landslide management, 398

Risk assessment, decision making and consultation, 403

Glossary of terms 405

References 412

Index 443

Contents

Chapter 3 Qualitative and semi-quantitative risk assessment 129

Introduction, 129

Risk registers, 130

Relative risk scoring, 134

Risk ranking matrices, 142

Relative risk rating, 148

The FMECA approach, 152

Qualitative risk assessment: an easy option? 161

Chapter 4 Estimating the probability of landsliding 164

Introduction, 164

Discrete events, 168

Multiple events, 175

Continuous probability distributions and sampling, 178

Subjective probability, 180

Estimating probability from historical landslide frequency, 183

Estimating probability from landslide-triggering events, 195

Estimating probability through expert judgement, 206

Estimating probability of cliff recession through simulation models, 226

Estimating probability through use of stability analysis, 234

Estimating probability: precision or pragmatism? 242

Chapter 5 Estimating the consequences 244

Introduction, 244

Using the historical record, 247

A framework for adverse consequences, 250

Loss of life and injury, 252

Direct and indirect economic losses, 259

Intangible losses, 263

Ground behaviour, 265

Elements at risk, 270

Exposure, 270

Vulnerability, 275

Consequence models, 284

Multiple outcome consequence models, 308

Complex outcomes and uncertain futures, 319

Chapter 6 Quantifying risk 321

Introduction, 321

Current annual risk, 322

Cliff recession risk, 327