Hot to cold: the exceptional mobility and hazard of volcanic block and ash flows
Ten percent of the world’s population (i.e. 100s of millions) live within 100 km of an active volcano. During all explosive volcanic eruptions pyroclastic density currents (PDCs) can form – high temperature mixtures of rock and gas that rapidly flow away from the volcanic vent. These phenomena are the most lethal of all volcanic hazards and are responsible for more than a third of volcanic related fatalities globally. The most common type of pyroclastic density current – block and ash flows (BAFs) occur when lava flows or domes collapse. These collapses and BAFs often occur repeatedly during times of volcanic unrest and thus cause prolonged evacuation orders and community disruption.
We currently lack adequate knowledge of the underlying flow physics to accurately forecast these flows, thus any hazard maps and mitigation strategies currently produced are inherently limited. To improve our model forecasts, we need to understand the complex internal flow dynamics within these ‘opaque’ and hazardous flows. A key knowledge gap, specifically to be addressed by this project, is determining how ambient cold air is entrained into BAFs during their transport. This entrained air leads to enhanced flow mobility (increasing flow runout distances) and modifies their thermal structure (changing their impact).
Within this project you will (1) have the opportunity to conduct fieldwork on Mt Meager, Canada to unravel the range of particle properties transported within natural BAFs; (2) perform laboratory experiments to understand how, and the rates at which, ambient air is entrained; (3) calculate the thermal evolution of BAFs and resulting temperature profiles; (4) integrate this new quantitative flow knowledge into volcanic hazard maps in partnership with Natural Resources Canada.
Eligibility.
Candidates shall be good honours graduates in appropriate subject areas, of a recognised university or comparable university, or persons holding equivalent qualifications who show evidence of exceptional ability, or who have demonstrated their ability in graduate studies.
Email address for enquiries.
thomas.jones@lancaster.ac.uk