The Arias intensity (IA) is a measure of the strength of a ground motion.
[1] It determines the intensity of shaking by measuring the acceleration of transient seismic waves.
It has been found to be a fairly reliable parameter to describe earthquake shaking necessary to trigger landslides.
[2] It was proposed by Chilean engineer Arturo Arias in 1970.
[3] The Arias Intensity could also alternatively be defined as the sum of all the squared acceleration values from seismic strong motion records.