Rheological Properties of Pyroclastic Flow Mixtures

Pyroclastic density currents are among the most fatal events associated with volcanic hazards. When pyroclastic density currents escape their confining channels and become unconfined, then they inundate the inhabited areas and destroy everything in their path. Pyroclastic density currents (PDCs) are hot mixtures of volcanic rock and gases that can flow long distances at velocities of tens to hundreds of kilometers per hour from the source.  PDCs are complex volcanic flows whose dynamics, occurrence, and flow paths are mostly unpredictable. In this project, we are investigating the rheological properties of pyroclastic mixtures sampled from the PDCs’ deposits of the Pollena 472 ACE eruption of Mt. Vesuvius (Italy). First, we characterized the grain size distribution, density, and morphology of the used mixtures, as well as performed BET analysis and Shear cell experiments. Then, using an Anton Paar MCR702e rheometer, we Conduct Shear cell experiments to gain insight into the mobility of the studied granular materials, specifically by measuring their internal friction angle, cohesion (if any), unconfined yield strength, and flowability. In this presentation, I will present preliminary results of all my performed experiments and their implications on the rheology of Pyroclastic Density Currents.