Friction weakening in granular flows deduced from seismic records at the Soufrière Hills Volcano, Montserrat

Clara Levy*, Anne Mangeney, Fabian Bonilla, Clément Hibert, Eliza S. Calder, Patrick J. Smith

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Accurate modeling of rockfalls and pyroclastic flows is still an open issue, partly due to a lack of measurements related to their dynamics. Using seismic data from the Soufrière Hills Volcano, Montserrat, and granular flow modeling, we show that the power laws relating the seismic energy Es to the seismic duration ts and relating the loss of potential energy ΔEp to the flow duration tf are very similar, like the power laws observed at Piton de la Fournaise, Reunion Island. Observations showing that tf≃ts suggest a constant ratio Es/ΔEp≃10-5. This similarity in these two power laws can be obtained only when the granular flow model uses a friction coefficient that decreases with the volume transported. Furthermore, with this volume-dependent friction coefficient, the simulated force applied by the flow to the ground correlates well with the seismic energy, highlighting the signature of this friction weakening effect in seismic data.

Original languageEnglish
Pages (from-to)7536-7557
Number of pages22
JournalJournal of Geophysical Research. Solid Earth
Volume120
Issue number11
Early online date10 Oct 2015
DOIs
Publication statusPublished - 6 Nov 2015

Keywords

  • Friction weakening
  • granular flow
  • seismic records
  • Soufrière Hills Volcano

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