VOLCANIC PLUME MONITORING USING ATMOSPHERIC ELECTRIC-POTENTIAL GRADIENTS

By monitoring perturbations of the natural atmospheric electric potent ial gradient, it is possible to detect and track particle laden volcan ic plumes. The perturbations are produced by electrical charge that re sides on the solid particles and liquid droplets of the plume, and the ions within it. A network of potential gradient monitoring stations a round a volcano can provide data on eruption time, magnitude, plume di spersion direction and areas of ashfall. Our laboratory experiments ha ve produced electrically charged ash by fragmenting pumice. These resu lts support the theory that charging is due to the magma fragmentation process and should therefore be ubiquitous in all particulate volcani c plumes.