Ground motion intensity measures (IMs) are widely used in Performance-Based Earthquake Engineering (PBEE) to quantify seismic hazard and potential demands on structures. The IMs are a particularly useful set of summary statistics by which to validate ground motion simulation results as they enable quantitative comparison between simulation and observation data, in a format consistent with that provided by conventional empirical ground motion models.

We have developed a software workflow that computes and plots a wide range of IM values from simulation and/or observation time series. Available IM metrics include peak ground acceleration (PGA), peak ground velocity (PGV), cumulative absolute velocity (CAV), Arias intensity (AI), duration (Ds575, Ds595), modified Mercalli intensity (MMI) and pseudo-spectral acceleration (pSA) with a range of periods between 0.01 and 10.0 seconds. IM values can also be aggregated for a specified location into a single comma-separated-value (CSV) file, and metadata, such as source-to-site distance metrics (e.g. Rrup and Rjb) can also be computed and stored.

We have recently extended this workflow to also include ‘advanced IMs’, which are based on the results of response history analysis of complex structural and/or geotechnical systems - typically measures such as inter-storey drift and floor accelerations, but can be any generic measure of seismic response, in general. This is an open-source software project that provides engineering seismologists and structural/geotechnical earthquake engineers with an easy-to-use IM calculation and plotting capability, seen as a critical toolchain necessary to progress the comprehensive validation of ground motion simulation methods from the perspective of developers as well as users.