Friction weakening in granular flows deduced from seismic records at the Soufrière Hills Volcano, Montserrat
LEVY ; MANGENEY ; BONILLA ; HIBERT ; CALDER ; SMITH
Type de document
ARTICLE A COMITE DE LECTURE REPERTORIE DANS BDI (ACL)
Langue
anglais
Auteur
LEVY ; MANGENEY ; BONILLA ; HIBERT ; CALDER ; SMITH
Résumé / 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 ?Ep 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/?Ep?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.
Source
Journal of Geophysical Research : Solid Earth, num. 11
Editeur
American Geophysical Union
