Viscous flow of magmas from Unzen volcano, Japan - Implications for magma ascent and emplacement
Final Report Abstract
The main results of project can be summarised as follows. A new uniaxial high-load press was brought into service for the investigation of lava under natural strain rate conditions. The newly established press facility was employed in the first experimental determination of viscous heating in deforming lava. A general law was extablished for the non-Newtonian rheology of crystal-rich dome lavas. The understanding of rheology and viscous heating was applied to a petrophysical analysis of the extrusion of lavas during the 1992-1994 Unzen eruption. An acoustic sensor monitoring system was applied to the deformation of dome lava near its failure conditions. The results yielded a clear acoustical record of lava failure, leading to new insights for the potential prediction of dome failure In nature. The scientific results of project have impacted substantially on the understanding of flow and failure of magma in explosive eruptions. Any one of the above advances might have been a sufficient return on the investment of this grant. Together, they form a remarkable integral step forward in the understanding and modelling of lava dome deformation and failure. The advances achieved here have also be a major impetus in the development of the successful ERC Advanced Grant EVOKES. In a broader perspective they have served to bring together two previously disparate fields, experimental volcanology and rock deformation, to help fuse a new area of study – the petrophysics of volcanic eruptions. Germany can be said to be leading this initiative at present.
Publications
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(2007) High-load, hightemperature deformation apparatus for synthetic and natural silicate melts. Review of Scientific Instruments, 78(7), Article Number 075102
Hess, K.U., Cordonnier, B., Lavallee, Y., and Dingwell, D.B.
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(2007) Non-Newtonian rheological law for highly crystalline dome lavas. Geology, 35(9), 843-846
Lavallee, Y., Hess, K.U., Cordonnier, B., and Dingwell, D.B.
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(2008) Seismogenic lavas and explosive eruption forecasting. Nature, 453(7194), 507-510
Lavallee, Y., Meredith, P.G., Dingwell, D.B., Hess, K.U., Wassermann, J., Cordonnier, B., Gerik, A., and Kruhl, J.H.
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(2008) Viscous heating in rhyolite: an in situ determination. Earth and Planetary Science Letters, 275, 121-126
Hess, K.U., Cordonnier, B., Lavallée, Y., and Dingwell, D.B.
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(2009) Rheological properties of dome lavas: case study of Unzen volcano. Earth and Planetary Science Letters, 279, 263-272
Cordonnier, B., Hess, K.U., Lavallee, Y., and Dingwell, D.B.
