Abstract
Volcanic clasts are known to have highly nonspherical and irregular shapes, with physical, chemical, and optical characteristics significantly different from those of spherical particles. Numerous studies show the importance of particle shape on various particle properties, such as their scattering and aerodynamical behavior. Nevertheless, volcanic particles have often been approximated as spheres in numerical descriptions and observation strategies, in part because accurate shape characterization is challenging, time-consuming, and needs special equipment, and in part because scattering analysis is complicated for nonspherical shapes. The technological development of the last few decades years has provided various strategies for quantifying shape of volcanic particles rapidly (eg, image analysis) and accurately (eg, 3-D laser scanning). However, studies of particle shape are dispersed across various scientific fields, which, in some cases, lead to research redundancy or improper method implementation. The main goal of this chapter is to summarize state-of-the-art methods of characterizing particle size and shape, which are crucial for models of particle dispersal and sedimentation.
