Fig. 7

Best-fit viscoelastic model (blue line) based on grid search for ΔV _∞ and t _R . Fitted volume change at infinite time (ΔV _∞ ) is 0.13 ± 0.01 km³, relaxation time t _R = 2.23 ± 0.15 years. Relative to the start of the eruption (red line). Plotted with all observed data points (grey circles). The grey lines mark the upper and lower one sigma error bounds on the t _R and ΔV _∞ values calculated from a Monte Carlo analysis using 1000 simulations. a Viscoelastic model over a period of 20 years. b Model fit over the observation period