Defining disasters is not a simple task. Leaning (2008) proposes a broad concept that disasters are complex phenomena that create extensive consequences for human populations. According to the same author, there is, however, a general agreement on the characteristics that make an event a disaster: A disaster is an event that imposes severe and intense stress on a community that cannot be dealt with through deployment of the ordinary resources of that community. Disasters are events that require outside help. Time is also considered in some accepted definitions

9.1 Introduction 225 9.1.1 Disaster Classification 226 9.1.2 Stakeholders Affected by Disasters 227

9.2 Disaster Impact Analyses 227 9.2.1 Disaster Impact on the Infrastructure 228 9.2.2 Disaster Impacts on the Transportation Operation 229 9.2.3 Reconstruction Impacts 231 9.2.4 Disaster Risk Measurement 232 Quantitative Risk Measurement 233 Qualitative Risk Estimation 234

9.3 Business Continuity for Transportation 236 9.3.1 Facility Location 241

9.4 Conclusion 241 References 241

of disaster: Disasters are events that contain anticipatory warning signs (although often not observed or looked for) but impose a relatively abrupt impact. The consequences of that impact may persist for months or years. Moreover, most definitions focus on impacts on and consequences for human populations. Events such as earthquakes and floods that do not cause direct or indirect social, economic, or psychological disruptions are usually not registered as disasters and not counted in disaster databases.