PARTIcle Shape ANalyzer PARTISAN – an open source tool for multi-standard two-dimensional particle morphometry analysis

In volcanology, 2D morphometric analysis is a method often applied for quantitative characterization of eruptive products, used to compare tephra from different events or phases, infer eruptive styles and underlying clast generating mechanisms, or describe the aerodynamic behavior of tephra. Such particle shape analyses can be conducted using particle silhouettes or cross-sectional slices, obtained under by means of electron or optical microscope imagery. Over the course of the last years, a number of different morphometric systems have been used. Each of them uses its own nomenclature and mathematical definitions of shape-describing parameters, some of which can only be obtained using specific commercial software. With the PARTIcal Shape ANalyzer PARTISAN we present a freeware tool which parameterizes 2D shapes and provides a suite of shape descriptors, following the respective standards of the five most commonly used 2D morphometric systems. Use of PARTISAN will enable the user to study and archive the results of particle shape analysis in a format compatible with various published routines, thus increasing the potential for linking new work with results of work previously published by other groups. It will allow as well the cross-comparison of results obtained by these morphological routines. PARTISAN hence could be seen as a “Rosetta Stone” for volcanological particle morphometry, and opens the way towards an inter-group effort for a standardized 2D description of particle shapes.