Analog and FEM Models of Lava Dome Dynamics

P. Vincent[1], and P. Zevada[2]
[1]College of Earth, Ocean and Atmospheric Sciences, Oregon State University, Oregon
[2]Dept. of Tectonics and Geodynamics, Institute of Geophysics ASCR, v.v.i., Prague, Czech Republic

Extrusion of highly viscous lavas that spread laterally and form lava domes in craters of large volcanoes is associated with significant volcanic hazards. Gas overpressure driven fragmentation of the lava dome or collapse and slumping of marginal sections or entire mass of the dome can trigger dangerous pyroclastic flows that threaten surrounding populations up to tens of kilometers away.

We examine the non-linear dynamics of lava dome growth by developing two phase non-Newtonian FE codes to simulate the extrusion of thixotropic and pseudoplastic material into a brittle environment. The results are compared with analogue extrusion models to better understand lava dome dynamics and mode transitions.