# Inertia

Inertia is an analysis export variable available in exported integration analyses.

It reports the spread as the sum of squared distances from the Center_of_mass, weighted by the sv at each distance and normalized by the total sa of the domain. The exported Inertia is equivalent to the 'Inertia' as used by Urmy et al (2012).

## Algorithm

Where:

I is the Inertia (m2). CM is the Center_of_mass. z is the depth (m) of a sample in the analysis domain. sv(z) is the sample volume-backscattering coefficient at z.

Sv (dB re 1m-1) is the (mean) Volume backscattering strength of the sample at z.

Notes:Thresholded Sv (dB) values are handled as 0 in the linear domain.