Electrical Conductivity Analysis of Volcanic Ash and Particle Shape data

In part, this study seeks to understand the influence of particle shape on the electrical conductivity of volcanic ash. Grain conductivity values were calculated by applying spherical, oblate (flattened spheroids), and prolate (elongated spheroids) ellipsoidal morphological parameters within a general effective media (GEM) equation to understand the impact of particle shape on the calculated grain conductivity. These equations require an average aspect ratio value for the eight volcanic ash samples analyzed in the study. This dataset contains the measured aspect ratio values of the milled samples and Alaska samples of 1000 randomly selected grains that presented a flat face optimal for shape and size measurements to get a representative sampling. Values were determined from backscatter electron images (BSE) from a scanning electron microscope (SEM). Shapes were analyzed using images freeware. This dataset also contains grain conductivity calculations for the three morphological parameters using an averaged aspect ratio value. Results show that values remain within the same order of magnitude between the morphological equations. However, the volume conductivity values are all lower than the grain conductivities using a spherical, prolate, and oblate shape assumption. It was determined that particle shape have a limited effect on grain conductivities. However, aspect ratio is not a very sensitive parameter to quantify grain shapes, so more analysis is needed to fully understand the relationship between electrical conductivity of volcanic ash and particle shape.