Physical modeling of small-volume pyroclastic flows
Abstract
Small-volume p yroclastic flows represent common hazardous phenomena generated by the repetitive partial collapse of a growing lava-dome. Their fluid- like behavior can be reproduced using fluidization techniques, commonly used in industrial systems, which lead to the formation of homogeneous particulate suspension s that can be represented as an equivalent fluid of similar density and viscosity . We present here a simplified physical model based on shallow-water equations. T h e mixture is approximated as an inviscid fluid that mov es as a plug flow that thins during propagation by sedimentation with negligible energy dissipation. The runout duration is control l ed by the time taken to the particles to settle during transport. We present here an operational model based on one-dimensional n umerical simulations performed using a finite volume scheme. When compared to laboratory experiments involving the dam-break flows of particulate suspensions, the model proves to be capable of consistently reproduc ing the first-order feature of these flows. While the exten sion to natural cases is not obvious , especially because of the lack of available measure ments of the key parameters from field analyses , simulations allow to recover the relevant order of magnitude for both the runout distance and duration, a s well as it is able to provide consistent deposit morphologies .
Keywords : Pyroclastic flows , numerical model , particulate suspensions, fluidization, scaling laws.- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMV008.0021J
- Keywords:
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- 8404 Volcanoclastic deposits;
- VOLCANOLOGY;
- 8428 Explosive volcanism;
- VOLCANOLOGY;
- 8445 Experimental volcanism;
- VOLCANOLOGY;
- 8486 Field relationships;
- VOLCANOLOGY