Dataset of particle size distribution data of Holocene volcanic ashes of NW Argentina

Grain size distributions were determined in volcanic ash samples using a Malvern Mastersizer 2000 particle analyser, equipped with a laser diffractometer (ultrasonic water disaggregation: Hydro MU system; absorption: 0.1; refractive index: 1.52; measurement time: 20 s; obscuration: 10–20%; and pump speed: 2500 rpm, 3 measures), following the recommended procedures of the International Volcanic Health Hazard Network (IVHHN, www.ivhhn.org). This technique measures particles of 0.1–1000 μm using the Mie Theory; due to this limitation, only distal ash samples with maximum grain sizes of < 1 mm for the complete deposit (not grain fractionated) were analysed. The particle-size abundance is reported as the volume percentage of equivalent spherical diameter. Contact person: Fernandez-Turiel, J. L., [e-mail]