We use a boundary element approach to study the problem of a large, magma-filled dyke embedded in a fractured, damaged medium. The numerical simulations show that the dyke opening and the crack extension force at the dyke tip increases with increasing fracture density. We show that this behaviour can at moderate fracture densities be predicted by an effective media model. Simple analytical formulae are given for the increasing average opening of the dyke and the decreasing fracture toughness as functions of increasing fracture density. The numerical and the theoretical results are found to be in good agreement. In a first application we tested the model by using GPS deformation and seismicity data from a recent lateral magma intrusion in Izu islands, Japan. This shows that a simple comparison of the distance change and the cumulative earthquake number enables the study of the stability of the dyke intrusion. The method seems to distinguish whether the dyke opening is actively driven by magma influx or passively driven by an expansion due to fracturing.

Dyke emplacement in fractured media: application to the 2000 intrusion at Izu islands, Japan

Rivalta, E.;
2004

Abstract

We use a boundary element approach to study the problem of a large, magma-filled dyke embedded in a fractured, damaged medium. The numerical simulations show that the dyke opening and the crack extension force at the dyke tip increases with increasing fracture density. We show that this behaviour can at moderate fracture densities be predicted by an effective media model. Simple analytical formulae are given for the increasing average opening of the dyke and the decreasing fracture toughness as functions of increasing fracture density. The numerical and the theoretical results are found to be in good agreement. In a first application we tested the model by using GPS deformation and seismicity data from a recent lateral magma intrusion in Izu islands, Japan. This shows that a simple comparison of the distance change and the cumulative earthquake number enables the study of the stability of the dyke intrusion. The method seems to distinguish whether the dyke opening is actively driven by magma influx or passively driven by an expansion due to fracturing.
File in questo prodotto:
Eventuali allegati, non sono esposti

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/776181
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 16
  • ???jsp.display-item.citation.isi??? 16
social impact