III. From precursors to eruption  

III.9 Understanding pyroclastic density currents through analysis of their deposits

Pete Rowley, University of Portsmouth UK; peter.rowley@port.ac.uk
Rebecca Williams, University of Hull UK; Rebecca.Williams@hull.ac.uk
Brittany Brand, Boise State University, USA; brittanybrand@boisestate.edu

Deposits from pyroclastic density currents (PDCs) are one of the richest sources of information for developing our understanding of flow processes and mechanics. PDCs themselves are opaque to most observation, and can be both temporally and spatially variable. Improving our ability to interpret deposits enables us to better understand the transport and depositional processes, ultimately improving both our volcano histories and our future hazard mitigation attempts.

Experimental work, numerical modelling, and field studies must be used together to address PDC processes and emplacement dynamics. This session aims to establish our current understanding of factors such as rheology, density stratification, deposition and segregation timescales, mass flux variation, and topographic controls, and the impact these variables have on flow boundary and emplacement conditions (e.g. erosion, lithofacies deposition, bedform stability and formation, and deposit accumulation rates).  This session covers the complete PDC range from unsteady currents through to sustained flows, and the gamut from dense granular flows to fully dilute turbulent clouds and surge.