Table 1 Definitions and context of key terminology used within this paper
Term | Definition | Paper specifics | References |
|---|---|---|---|
Airport | Surface transportation site consisting of airfield and facilities used to service aircraft. | Surface and near-surface (< 10 m above ground) environmental conditions at airfields are considered when referring to airports. | |
Exposure | People, property, systems, or other elements present in hazard zones that are thereby subject to potential losses. | ||
Fragility function | Probabilistic vulnerability models that describe the probability that a damage or functional state will be reached or exceeded for a given hazard intensity. | Only fragility functions for volcanic ash are discussed in detail. | Singhal and Kiremidjian 1996, Choi et al. 2004, Rossetto et al. 2013, Tarbotton et al. 2015 |
Hazard | A phenomenon that may cause loss of life, injury or other health impacts, property damage, loss of livelihoods and services, social and economic disruption, or environmental damage. | Hazard is referred to in the context of a dangerous phenomenon from volcanoes (i.e. volcanic tephra, pyroclastic density currents, lava flows, lahars). | UNISDR 2009 |
Hazard Intensity Metric (HIM) | A measure used to describe the intensity of a volcanic hazard at a particular site, which is the independent variable of vulnerability and fragility functions. | Ash thickness is often used as the HIM for volcanic ash fragility functions. Alternative HIMs are explored here including ash-settling rate and particle size. | |
Impact | The effect a hazardous event has on an exposed system. Defined as a function of the hazard, and the vulnerability and exposure of a system (I = H*V*E). | Multiple impact types are inferred when discussing impact. | |
Impact State (IS) | States of damage or disruption defined by qualitative impact descriptions. | These are numbered numerically with 0 being “no damage or disruption”, and increasing numbers referring to an increasing level of damage or disruption. | |
Impact type | An individual feature of an infrastructure system that can be affected by the function of hazard, vulnerability and exposure. | Surface transportation impact types include skid resistance reduction, visibility impairment, road marking coverage and engine air inlet filter blockage. | |
Maritime | Surface transportation connected with the sea. | Covers trade shipping, recreational boating and ferry services. | |
Mitigation | The lessening or limitation of the adverse impacts of hazards and related disasters. | UNISDR 2009 | |
Rail | Surface transportation on wheeled vehicles running on rails. | Covers electric and diesel modes on conventional tracks. | |
Risk | The combination of the probability of an event and its negative consequences. | A volcanic hazard is implied to be the “event”. | UNISDR 2009 |
Road | Surface transportation on dedicated sealed or unsealed routes. | We generally refer to paved surfaces, particularly asphalt concrete. | |
Skid resistance | The force developed when a tyre that is prevented from rotating slides along apavement surface. | (Often referred to as traction in post-eruption literature.) | |
Surface transportation | Transportation types on land or water used to convey passengers and/or goods. | Road, rail and maritime transport are covered, as well as transport that occurs on the ground at airports. | |
Visual range | The longest distance that a large, black object can be seen against the sky at the horizon with the unaided eye. | Used as a measure of visibility. | |
Vulnerability | The characteristics and circumstances of a community, system or asset that make it susceptible to the damaging effects of a hazard. | Largely transportation systems or assets are referred to. | UNISDR 2009 |
Vulnerability function | A correlation of hazard intensity to a component’s damage or function loss as a value relative to total impact or as an economic cost. | We generally refer to fragility functions instead, which incorporate probability. | Wilson 2015 |