Damià Benet, Fidel Costa, Kévin Migadel, Daniel W. J. Lee, Claudia D’Oriano, Massimo Pompilio, Dini Nurfiani, Hamdi Rifai

Volcanic ash is made of particles smaller than 2 mm and is produced during volcanic eruptions. Studying the properties of volcanic ash is key for a range of applications, including volcano monitoring. However, given the large variety of textures, colors, and shapes of particles from different eruptions and volcanoes it is challenging to classify them in a reproducible and systematic manner. Here, we present an open access web-based platform that displays the contents of a database of volcanic ash particles, VolcAshDB (https://volcashdb.ipgp.fr/). Particle data includes optical microscope images, physical characteristics of the shape, texture and color, and a classification label with the particle type (free-crystal, altered material, juvenile or lithic). It currently hosts data of 12,044 particles from 53 samples across 13 volcanoes that can be visualized and downloaded in a user-friendly manner. The database has already been used to develop particle classifiers with Machine Learning. We plan to continue it to grow and encourage the volcano community to contribute towards standardizing volcanic ash classification.