Selective Measurement of Volcanic Ash Flow-Rate

The ash fall-out, following explosive activity of volcanoes, 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 multisensor system for the monitoring of ash fall-out phenomena with particular regards to average granulometry and ash flow-rate estimation. Moreover, the system must be selective with respect to volcanic ash against other sediments such as dust, sand, or soil. This paper is particularly focused on the methodology adopted for ash flow-rate estimation and discrimination from other types of sediments. The main idea to accomplish the first task is to measure the time interval required to collect a fixed amount of ash inside an instrumented tank. To implement ash selectivity task, the intrinsic paramagnetic property of ash particles is exploited. Main claims and novelties of this paper can be identified in the low-cost adopted sensing methodologies with respect to the traditional instrumentation and the selectivity with respect to volcanic ash. Availability of low-cost multisensor nodes allows for the realization of high-density networks for the early warning of ash fall-out phenomenon. Experimental tests have been performed on the system developed by using ash erupted by the Etna volcano.