Subcritical dyke propagation in a host rock with temperature-dependent viscoelastic properties

Abstract

S U M M A R YIn this paper, we examine the effects of temperature-dependent viscoelastic properties of the host rock on the subcritical growth of a dyke from a magma chamber. A theoretical relationship between the velocity of subcritical dyke growth and dyke length is established using a perturbation solution of stress intensity factor at the dyke tip and a viscoelastic crack growth theory in which the temperature-dependent creep properties are taken into account. The temperature field around the dyke is calculated using an analytic solution. The numerical results for a dyke subcritically propagating from a magma chamber indicate that while the general dyke growth characteristics are similar to those with constant creep properties, the subcritical dyke growth velocity is increased by an order of magnitude by considering the temperature dependence of the creep properties. Hence, the subcritical growth duration before the dyke reaches the unstable growth state is significantly shortened.

Laboratory simulations of tensile fracture development in a volcanic conduit via cyclic magma pressurisation

“…Once nucleated, fractures can further propagate due to perturbation of the elastic energy release rate or the stress intensity factor at the crack tips (Inglis, 1913;Broek, 1982). In the case of dyke propagation at high temperatures, the viscoelastic response of the rock, creep (subcritical crack growth) at the dyke tips may accelerate the propagation by one order of magnitude (Chen and Jin, 2011). Experimental studies have mapped out the fracture toughness of volcanic rocks subjected to a range of temperatures and confining pressures (Rocchi et al, 2004;Balme et al, 2004;Smith et al, 2009).…”

Modeling magmatic accumulations in the upper crust: Metamorphic implications for the country rock

“…Following the approach by Jellinek and DePaolo (2003) and Chen and Jin (2011), under high temperatures and confining pressures, crustal rocks are assumed to behave viscoplastically or also referred to as a solid-state creep flow. Thus, the host rock rheology can be described by the Weertman-Dorn power-law formulation where the relationship between strain rate and deviatoric stress is defined as follows (Jellinek and DePaolo, 2003 and references therein; Chen and Jin, 2011):…”

“…14 distribution and calculated using the Arrhenius formulation (Del Negro et al, 2009;Chen and Jin, 2011;Gregg et al, 2012) :…”