Volcanic Hazards Risk Assessment

Abstract

This chapter reviews the physical characteristics of a wide range of volcanic hazards pertinent to assessments of vulnerability and risk with respect to humans, buildings, lifelines, and other infrastructure. When deaths related indirectly to eruptions are excluded, the record of fatalities from eruptions is dominated by a few catastrophic events that produced numerous deaths as a result of pyroclastic flows, lahars, or tsunamis.

Risk assessment can be readily carried out through the development of a series of scenarios in which eruption magnitudes, hazard mixtures, and the vulnerabilities of personnel and infrastructure are adequately considered. Because not all hazards are characteristic of volcanoes, it is necessary to estimate probabilities of recurrence for specific regions, volcanoes, and eruptions. A relative risk index produced for Papua New Guinea volcanies — based on hazard frequency, area affected, and potential building damage — indicates the dominant importance of tephra fall.

Damage mechanisms affecting buildings and contents vary widely, but it is clear that adequate risk assessment requires much better information than is currently available on the consequences of eruptions. Even less is known about the vulnerabilities of lifelines or the consequences of secondary hazards. Increased attention must be paid to the potential consequences of maximum possible eruptions in scenario development and risk assessment.