Tuffisites, the products of subsurface fragmentation, transport and deposition, are common in explosive volcanic environments. Their study provides direct insight to the mechanical processes operating within volcanic conduits. Here we document the influence of the presence of coherent tuffisite veins on the physical properties of andesitic rocks. We find that (1) compressive strength is unaffected by the presence and/or orientation of tuffisites, (2) permeability doubles when tuffisites are oriented favorably (at 45° to the fluid flow direction), and (3) ultrasonic wave velocities show a continuous increase with depth, independent of vein presence and orientation. Although the influence of tuffisites on andesitic rock properties determined here is modest, we emphasize that the material tested represents the post-eruptive state of tuffisite. Thus, these results likely delineate the upper and lower boundaries of strength vs. permeability and porosity, respectively. Our evidence suggests that, via compaction and lithification, tuffisites may restore the strength of the volcanic host-rocks to that of their pre-tuffisite values.

Strength and permeability recovery of tuffisite-bearing andesite

KOLZENBURG, Stephan;
2012-01-01

Abstract

Tuffisites, the products of subsurface fragmentation, transport and deposition, are common in explosive volcanic environments. Their study provides direct insight to the mechanical processes operating within volcanic conduits. Here we document the influence of the presence of coherent tuffisite veins on the physical properties of andesitic rocks. We find that (1) compressive strength is unaffected by the presence and/or orientation of tuffisites, (2) permeability doubles when tuffisites are oriented favorably (at 45° to the fluid flow direction), and (3) ultrasonic wave velocities show a continuous increase with depth, independent of vein presence and orientation. Although the influence of tuffisites on andesitic rock properties determined here is modest, we emphasize that the material tested represents the post-eruptive state of tuffisite. Thus, these results likely delineate the upper and lower boundaries of strength vs. permeability and porosity, respectively. Our evidence suggests that, via compaction and lithification, tuffisites may restore the strength of the volcanic host-rocks to that of their pre-tuffisite values.
2012
3
191
198
http://www.solid-earth.net/3/191/2012/se-3-191-2012.html
S. Kolzenburg; M. Heap; Y. Lavallee; J. Russell; P. Meredith; D. B. Dingwell
File in questo prodotto:
File Dimensione Formato  
se-3-191-2012.pdf

Accesso aperto

Tipo di file: PDF EDITORIALE
Dimensione 845.36 kB
Formato Adobe PDF
845.36 kB Adobe PDF Visualizza/Apri

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/2318/150800
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 57
  • ???jsp.display-item.citation.isi??? 56
social impact