Stability of volcanic ash aggregates and break-up processes

• Published in: Scientific reports Vol. 7; no. 1; pp. 7440 - 11
• Main Authors: Mueller, Sebastian B., Kueppers, Ulrich, Ametsbichler, Jonathan, Cimarelli, Corrado, Merrison, Jonathan P., Poret, Matthieu, Wadsworth, Fabian B., Dingwell, Donald B.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 07.08.2017; Nature Publishing Group; Nature Portfolio
• Subjects: 704/172/4081; 704/2151/598; Aggregates; Disaggregation; Dispersal; Humanities and Social Sciences; Impact tests; multidisciplinary; Science; Science (multidisciplinary); Sedimentation; Size distribution; Volcanic ash
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-017-07927-w

Numerical modeling of ash plume dispersal is an important tool for forecasting and mitigating potential hazards from volcanic ash erupted during explosive volcanism. Recent tephra dispersal models have been expanded to account for dynamic ash aggregation processes. However, there are very few studies on rates of disaggregation during transport. It follows that current models regard ash aggregation as irrevocable and may therefore overestimate aggregation-enhanced sedimentation. In this experimental study, we use industrial granulation techniques to artificially produce aggregates. We subject these to impact tests and evaluate their resistance to break-up processes. We find a dependence of aggregate stability on primary particle size distribution and solid particle binder concentration. We posit that our findings could be combined with eruption source parameters and implemented in future tephra dispersal models.