Landslides

Published by the American Geophysical Union as part of the Water Resources Monograph Series, Volume 18.

Landslides are a constant in shaping our landscape. Whether by large episodic, or smaller chronic, mass movements, our mountains, hills, valleys, rivers, and streams bear evidence of change from landslides. Combined with anthropogenic factors, especially the development and settlement of unstable terrain, landslides (as natural processes) have become natural disasters.

This book charts our understanding of landslide processes, prediction methods, and related land use issues. How and where do landslides initiate? What are the human and economic consequences? What hazard assessment and prediction methods are available, and how well do they work? How does land use, from timber harvesting and road building to urban and industrial development, affect landslide distribution in time and space? And what is the effect of land use and climate change on landslides?

This book responds to such questions with:

• Synopses of how various land uses and management activities influence landslide behavior

• Analyses of earth surface processes that affect landslide frequency and extent

• Examples of prediction techniques and methods of landslide hazard assessment, including scales of application

• Discussion of landslide types and related costs and damages

Those who study landslides, and those who deal with landslides, from onset to after-effects—including researchers, engineers, land managers, educators, students, and policy makers—will find this work a benchmark reference, now and for years to come.

Preface vii

1. Introduction and Overview of Landslide Problems 1

Overall Significance of Landslides 2

Distribution of Landslide Hazards Worldwide 9

Loss of Human Life 10

Economic Consequences 13

Examples of Detailed Economic Analyses of Landslide Damages 15

Other Environmental Impacts 20

2. Characteristics of Various Types of Landslides 23

Classification Systems 23

Broad Functional Categorization of Mass Wasting Processes 24

3. Natural Factors Influencing Landslides 41

Geological Factors 41

Geomorphic Factors 55

Hydrologic Factors 67

Seismicity 110

Volcanic Activity 117

4. Landslide Analysis 121

Analysis of Stresses Within Slopes and Initiation Mechanisms of Landslides 121

Quantifying Landslide Trigger Mechanisms 124

Primary Causes of Landslides 129

Problems in Applying Theoretical Stability Analysis to Natural Hillslopes 134

Hazard Assessment and Prediction Methods 139

Overview of Techniques and Methodologies 139

Terrain Hazard Mapping 139

Simple Rainfall-Landslide and Earthquake-Landslide Relationships 145

Multi-Factor, Empirical Landslide Hazard Assessment 150

Distributed, Physically Based Models 155

Overview of Landslide Hazard Assessment and Prediction Methods 160

Land Use and Global Change 163

Timber Harvesting 163

Roads and Other Transportation Corridors 183

Conversion of Forests to Agricultural Lands and Plantations 203

Management Effects 203

Control and Avoidance Practices Amidst the Politics 206

Steepland Grazing and Grasslands 209

Management Effects 209

Avoidance and Control Practices 211

Fire 213

Management Effects 213

Avoidance and Control Practices 216

Urban, Residential, and Industrial Development 217

Background and Vulnerability 217

Direct Effects 219

Avoidance and Mitigation Measures 223

Urban planning and regulation 224

Control and mitigation measures 229

Mining 230

Tourism and Recreation 235

Global Climate Change 236

7. Summary 239

Notation 243

References 247

Index 307

Roy C. Sidle is the author of Landslides: Processes, Prediction, and Land Use, published by Wiley. Hirotaka Ochiai is the author of Landslides: Processes, Prediction, and Land Use, published by Wiley.