the Probable Maximum Loss (PML) are the loss expected associated to long return periods, for example 100, 200 or 500 years (depending on the hazard and the needs of the stakeholder).

Alternative or back-up means created within an infrastructure system to accommodate disruption, extreme pressures, or surges in demand. It includes diversity, i.e., the presence of multiple ways to achieve a given need or fulfil a particular function.

Ability of an infrastructure asset or system to perform the desired function based on specified requirements over time without interruption or degradation.

The ability of individuals, households, communities, cities, institutions, systems, and society to prevent, resist, absorb, adapt, respond, and recover positively, efficiently and effectively when faced with a wide range of risks, while maintaining an acceptable level of functioning and without compromising long-term prospects for sustainable development, peace and security, human rights and well-being for all. (https://unsdg.un.org/sites/default/files/2021-09/UN-Resilience-Guidance-Exec-Summ-Sept). (UN Chief Executive Board, 2020)

For its part, CDRI defines disaster resilient infrastructure as “Infrastructure systems and networks, the components, and assets thereof, and the services they provide, that are able to resist and absorb disaster impacts, maintain adequate levels of service continuity during crises, and swiftly recover in such a manner that future risks are reduced or prevented”.

The value of reduced future asset loss and damage, avoided service disruption, wider social, economic, and environmental co-benefits, and reduced systemic risk, that accrue over the life cycle of an infrastructure system (Definition adopted in this Report)

Infrastructure systems and networks, the components, and assets thereof, and the services they provide, that are able to resist and absorb disaster impacts, maintain adequate levels of service continuity during crises, and swiftly recover in such a manner that future risks are reduced or prevented. 

The resilience of social, economic, territorial and environmental systems at all scales, that conditions the ability of infrastructure assets and the services they provide to resist and absorb disaster impacts. (Definition adopted in CDRI Biennial Report)

In the context of infrastructure, systemic risk is a cumulative risk to a system as an outcome of physical, biological, social, environmental, or technological shocks and stresses. These may be internal or external to the system. Impact on individual components of the system (assets, networks, and subsystems) becomes systemic due to interdependence and interactions between them.