Glossary

acceleration

Rate of change of velocity with time.

Acceleration Response Spectrum

A graphical plot of the maximum acceleration that structures having different characteristics will experience when subjected to a specific earthquake ground motion.

amplitude

The maximum value of a time-varying quantity.

critical infrastructure

Critical Infrastructure are “those physical facilities, systems, assets, supply chains, information technologies and communication networks which, if destroyed, degraded, compromised or rendered unavailable for an extended period, would significantly impact the social or economic wellbeing of Australia as a nation or its states or territories, or affect Australia’s ability to conduct national defence and ensure national security.”
Department of Home Affairs, Commonwealth of Australia (2023). Critical Infrastructure Resilience Strategy: February 2023, pg 4. Source: https://www.cisc.gov.au/about-us/our-strategy

facility

In this document facility is used as a shorthand for critical infrastructure (CI) facility. CI Facilities are physical structures with collection of components that work as a system and act as hubs for generation, processing, transmission, distribution, storage of lifeline products and services. These are high-value assets that are essential for the proper functioning of the CI networks and for the provisioning of essential services.

fragility

Fragility “implies easily damaged or broken, but is often used to describe the probability of a stated level of damage for a specific hazard, e.g. an earthquake.” Fragility is measured in terms of probability.

fragility function

fragility curves

Fragility function is a mathematical function that expresses the relationship between the probability of occurrence of some undesirable event given a measure of environmental excitation. As an example, the undesirable event can be a facility or component reaching or exceeding a defined damage state, given an environmental excitation produced by an earthquake, e.g., peak ground acceleration.

risk

ISO 31000 risk management vocabulary defines risk as the “effect of uncertainty on objectives”. It posits that the effect can be positive or negative deviation from expectations. In case of risk from natural hazards, the effect is almost always expected to be negative.

The Society for Risk Analysis Glossary offers a range of definitions of risk, based on the domain and use case. The one that is most relevant to natural hazard risk is “The combination of the probability of a hazard occurring and a vulnerability metric given the occurrence of the hazard.”

typology

“a system used for putting things into groups according to how they are similar : the study of how things can be divided into different types”.
Source: http://www.merriam-webster.com/dictionary/typology

vulnerability

Vulnerability refers to the concept of susceptibility of damage for a given entity. The entity can be a civil structure, a critical infrastructure facility, a component within such a facility, or a subset of population within a defined geographical area, etc. Vulnerability is measured in terms of loss.

vulnerability function

Vulnerability function is a mathematical function that depicts loss as a function of environmental excitation. It has several synonyms: vulnerability curves, damage functions, loss functions.