A Multi-Parametric Approach to Studying Volcanic Lightning Utilizing LMA Observations, Ash Characteristics, Plume Dynamics, seismic, and Infrasound Data at Sakurajima Volcano, Japan

The May-June 2015 eruptive period of Sakurajima Volcano, located in southern Kyushu Province, Japan was studied using 9 Lightning Mapping Array (LMA) units, 2 broadband seismometers, 6 infrasound sensors, and video footage of the plume (infrared and lowlight). Studies were performed in cooperation with the Sakurajima Volcano Observatory. In addition, several dozen temporal ash samples were taken during multiple eruptive episodes. Volcanic lightning, especially small vent discharges, was prevalent during this eruptive period. Previous work at Sakurajima has shown relationships between overall plume charge and ash grain size as well as mineral number density and maximum seismic amplitude. We take a multi-parametric approach and examine a full suite of ash grain characteristics (including grain size distributions, particle shapes, componentry, and microlite number densities), plume heights and eruption durations, seismic and infrasound amplitudes, and the occurrence of volcanic lighting. We seek to determine the underlying relationships between commonly measured parameters and the production of volcanic lighting