Fig. 5
From: Combined effusive-explosive silicic volcanism straddles the multiphase viscous-to-brittle transition
The consequence of viscoelasticity for the emplacement behaviour of magmas. a At Wi < 10−2, the maximum shear stress is τm = G∞Wi, and at Wi > 10−2, τm = 10−2G∞, which in the case of magmatic liquids is \(\tau _m = {\cal O}(10^2)\) MPa, consistent with a reanalysis of data for synthetic28, 44,45,46 and natural silicate liquids35. Here τm is computed from σm using the Trouton ratio for cylindrical geometry where appropriate. b The acoustic event number confirming fracture-formation during deformation of magmatic liquids at \({\mathrm{Wi}} \,\,\gtrsim\,\, 3 \times 10^{ - 3}\) and dominant acoustic activity at Wi = 0.01. c The viscoelasticity of a rhyolitic liquid oscillated at forcing frequency ω to low strain amplitudes, yielding a real G′ and imaginary G″ component of the elastic modulus47, 48 as a function of the Deborah number De = ωλr and showing the onset of elasticity at De = 10−2, consistent with all data (Figs. 2 and 4)
