# Glossary of Terms#

## asset#

An asset is something of value, which can include buildings and
population. For example, an asset can include an individual building
at a given location, or a number of buildings that are grouped and
co-located at a single location and are classified with the same
*taxonomy*.

## branch#

The simplest element in a logic tree; it belongs to a branch set where it represents one possible option among a finite number of alternatives. A branch is associated with a weight value (Scherbaum and Kuehn, 2011) if the branch set represents the epistemic uncertainty on a parameter or a model when the branch set is used to specify alternative models (e.g. district Magnitude-Frequency Distributions(MFDs)).

## branch set#

The structure describing the epistemic uncertainty on a specific parameter or model included in a logic tree structure. It ensembles a number of branches, each one representing a discrete alternative.

## consequence function#

Consequence functions describe the probability distribution of loss, given a performance level and are generally derived empirically.

## deductible#

A parameter used in the calculation of *insured losses* that
establishes the economic value that needs to be deducted from the
*ground-up losses*

## earthquake rupture#

A 3D surface - representing a portion or the entire fault surface - over which a slip event (i.e. an earthquake) occurs.

## event loss table#

A list of ruptures from a number of *stochastic event sets* and
respective aggregated losses.

## exposure model#

A set of *assets* grouped according to their geographical location,
*taxonomy* and value.

## fragility function#

the probability of exceeding a set of limit states, given an intensity measure level. These functions can be discrete or continuous.

## fragility model#

A set of *fragility functions* used to model the fragility of all the
*assets* in the *exposure model*.

## ground-motion field#

An object describing the geographic distribution around a rupture of a ground motion intensity measure.

## ground-motion prediction equation#

An equation that - given some fundamental parameters characterizing
the source, the propagation path and the site (in the simplest case
magnitude, distance and V_{S,30}) - computes the value *GM* of
a (scalar) ground motion intensity parameter.

## ground-up losses#

Total direct losses from a collection of assets due to a seismic event.

## insured losses#

Fraction of the *ground-up losses* that can be covered by the insurance
industry, ac- cording to a certain policy which defines *limits* and
*deductibles*.

## limit#

A parameter used in the calculation of *insured losses* that
establishes the maximum economic amount that can be covered by the
insurance industry, according to a certain insurance policy.

## loss disaggregation#

A methodology to investigate what are the characteristics of the seismic events that are contributing more significantly to the losses at a given location, in terms of fundamental variables commonly used to characterize seismic sources (e.g. magnitude, source-site distance, location).

## seismic source data#

An object containing the information necessary to completely describe a PSHA seismic source i.e. seismic source type, position, geometry and seismicity occurrence model.

## seismic source model#

An object containing a list of seismic source data.

## stochastic event set#

An object containing one or many *seismicity histories*.

## taxonomy#

Scheme used to classify the *assets*. For buildings, a classification
scheme has been proposed by *GEM* which considers a number of
attributes including lateral load resisting system and its material,
height, year of construction. The taxonomy is currently used to link
the *assets* in the *exposure model* to the relevant *vulnerability
function* or *fragility function*.

## vulnerability function#

A function that describes the probability distribution of loss ratio, conditioned on an intensity measure level. Currently only discrete vulnerability functions are supported.

## vulnerability model#

A set of *vulnerability functions* used to model the physical
vulnerability of all the *assets* in the *exposure model*.