Exploring the dynamics of Pyroclastic Density Currents in Large-Scale Experiments
| 27 Settembre 2017 | ore 11.30 | Dott. Gert Lube – Massey University (New Zealand) | Sala seminari – INGV Sezione di Pisa
Pyroclastic flows are the most lethal volcanic phenomena known to humankind. These red-hot mixtures of pyroclasts and gas exhibit astonishing fluidity, which allows them to transport large volumes of volcanic material across the Earth’s surface bypassing tortuous flow paths, rough substrates, flat and even up-sloping terrain. This enormous mobility has provoked a range of ‘friction-cheating’ theories to explain observed behaviour. However, the test of any these theories remain outstanding because direct observations and measurements of the processes operating inside real-world flows cannot be realized yet.
Here I report on unique nature-scaled pyroclastic flow experiments run at the eruption simulator PELE (Pyroclastic-flow Eruption Large-scale Experiment) in New Zealand. With up to 6 tonnes of hot volcanic material and air in motion, resulting pyroclastic density current analogues propagate for more than 35 meters at speeds of up to 100 kilometres per hour. The first part of the talk will introduce the audience to the range of eruption types, which PELE can synthesize and showcase the variety of multidisciplinary and international research programmes established around the large-scale facility to date. In the second part of the talk, I will report on some latest findings of Marsden-funded research at PELE. This seeks at better understanding and forecasting the remarkable fluidity of pyroclastic flows. This research suggests a new rheology for these types of geophysical mass flows, which can predict their hazard and runout potential.