TY - JOUR

T1 - Evidence for seismogenic fracture of silicic magma

AU - Tuffen, Hugh

AU - Smith, Rosanna

AU - Sammonds, Peter

PY - 2008/5/22

Y1 - 2008/5/22

N2 - It has long been assumed that seismogenic faulting is confined to cool, brittle rocks, with a temperature upper limit of 600 °C (ref. 1). This thinking underpins our understanding of volcanic earthquakes, which are assumed to occur in cold rocks surrounding moving magma. However, the recent discovery of abundant brittle–ductile fault textures in silicic lavas2, 3, 4 has led to the counter-intuitive hypothesis that seismic events may be triggered by fracture and faulting within the erupting magma itself. This hypothesis is supported by recent observations of growing lava domes, where microearthquake swarms have coincided with the emplacement of gouge-covered lava spines5, 6, leading to models of seismogenic stick-slip along shallow shear zones in the magma7. But can fracturing or faulting in high-temperature, eruptible magma really generate measurable seismic events? Here we deform high-temperature silica-rich magmas under simulated volcanic conditions in order to test the hypothesis that high-temperature magma fracture is seismogenic. The acoustic emissions recorded during experiments show that seismogenic rupture may occur in both crystal-rich and crystal-free silicic magmas at eruptive temperatures, extending the range of known conditions for seismogenic faulting.

AB - It has long been assumed that seismogenic faulting is confined to cool, brittle rocks, with a temperature upper limit of 600 °C (ref. 1). This thinking underpins our understanding of volcanic earthquakes, which are assumed to occur in cold rocks surrounding moving magma. However, the recent discovery of abundant brittle–ductile fault textures in silicic lavas2, 3, 4 has led to the counter-intuitive hypothesis that seismic events may be triggered by fracture and faulting within the erupting magma itself. This hypothesis is supported by recent observations of growing lava domes, where microearthquake swarms have coincided with the emplacement of gouge-covered lava spines5, 6, leading to models of seismogenic stick-slip along shallow shear zones in the magma7. But can fracturing or faulting in high-temperature, eruptible magma really generate measurable seismic events? Here we deform high-temperature silica-rich magmas under simulated volcanic conditions in order to test the hypothesis that high-temperature magma fracture is seismogenic. The acoustic emissions recorded during experiments show that seismogenic rupture may occur in both crystal-rich and crystal-free silicic magmas at eruptive temperatures, extending the range of known conditions for seismogenic faulting.

KW - volcano

KW - volcanic earthquake

KW - volcano seismicity

KW - fracture

KW - rupture

KW - brittle-ductile

KW - glass transition

KW - lava

KW - magma

KW - lava dome

KW - prediction

KW - earthquake

KW - hybrid event

KW - volcano-tectonic

KW - conduit

KW - obsidian

KW - andesite

KW - dacite

KW - experiment

KW - deformation

KW - acoustic emission

KW - frequency content

KW - faulting

KW - trigger mechanism

KW - high temperature failure

UR - http://www.scopus.com/inward/record.url?scp=44349112830&partnerID=8YFLogxK

U2 - 10.1038/nature06989

DO - 10.1038/nature06989

M3 - Journal article

VL - 453

SP - 511

EP - 514

JO - Nature

JF - Nature

SN - 0028-0836

IS - 7194

ER -