Figure 8

Acceleration dependence of the relative amplitude δz^′ at t  = 9.9 s. Here, the data for five different frequencies in the range of 40 to 200 Hz are plotted with different sizes (colors). Squares, triangles, and circles indicate regimes Ib (percolation), II (transition), and III (flame), respectively. Horizontal broken lines at δ z^′ = 0.1 and 0.6 mm indicate the threshold values of regimes II and III, respectively. A power-law fit to the 100 Hz data ( $\delta z^{\prime }=0.042{({\ddot{z}}_{\text{peak}})}^{1.04}$) is also shown.