Selective measurement of volcanic ash flow-rate

The ash fall-out following explosion activity of volcanoes like the Mount Etna, represents a relevant factor of risk for people and a serious hazard for air traffic. Researchers at DIEEI of the University of Catania are facing the challenge of developing a low-cost smart multisensor system for the monitoring of ash fall-out phenomena by measuring ash presence, average granulometry and ash flow-rate. Moreover, the system must be selective as respect to volcanic ash against others sediments such as dust, sand or soil. This paper is particularly focused on the methodology adopted for ash quantity estimation and discrimination from other types of sediments. The main idea is to use an array of coupled infrared diodes-phototransistors to estimate the level of ash collected in a tank and to measure the time interval between two subsequent levels. To implement the selectivity task the intrinsic magnetic property of ash particles is exploited. Experimental investigations have been performed using ash erupted by Etna volcano.