Repeated fracture and healing of silicic magma generate flow banding and earthquakes?

Tuffen, Hugh and Dingwell, D. B. and Pinkerton, Harry (2003) Repeated fracture and healing of silicic magma generate flow banding and earthquakes? Geology, 31 (12). pp. 1089-1092. ISSN 1943-2682

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Abstract

Textures in an exceptionally preserved effusive rhyolite conduit at Torfajokull, Iceland, indicate that rising magma repeatedly fractured and healed at shallow levels in the conduit (RFH process). Anastomosing tuffisite veins filled by fine-grained juvenile clasts were generated by shear fracture of highly viscous magma in the glass transition interval. Welding of the particulate material during subsequent deformation led to thorough healing of veins, allowing repeated fracture of the same body of magma. We propose that the RFH process is a rechargeable trigger mechanism for hybrid seismicity and show that the time scale of the process and the fractures formed by it are consistent with the repeat time and magnitude of hybrid earthquakes during silicic eruptions. The RFH process may also form the flow banding that is nearly ubiquitous in obsidian.

Item Type:
Journal Article
Journal or Publication Title:
Geology
Additional Information:
Geological Society of America, P.O. Box 9140, Boulder, CO 80301-9140 USA (http://www.geosociety.org)
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1900/1907
Subjects:
?? flow bandingobsidianvolcanic earthquakeshybrid earthquakestuffisitetuffisitesmagma fractureglass transitionicelandseismicityvolcanolava domelava domesseismic trigger mechanismgeologyqe geology ??
ID Code:
27351
Deposited By:
Deposited On:
01 Dec 2009 10:04
Refereed?:
Yes
Published?:
Published
Last Modified:
15 Jul 2024 10:34