Figure 4

Complexity measurements. (a,b) Illustrative contours and complexity-related variables from (a) the experimental fan with 4% clay and 3 \(\times\) 5 min runs. (b) A constant-slope modelled fan using the same fan apex position and median slope. (a,b) Left panels: top view showing each fan boundary (black outer line); contours of elevation for \(z_c\) from 0.2H, to 0.8H, where \(H=z_{apex}\) (gray lines). (a,b) right panels: center vertical cross-section (with distorted z scale). Black lines: bed plane of slope \(\tan \beta\) and approximate fan surface of slope \(\tan \alpha\); dashed line: horizontal plane of \(z=0\); bold line: contour plane \(z_c\) =0.4H. (c–f) complexity measurements from the experimental and field alluvial fans, modeled and measured, as noted in the upper left corners. open symbols: modelled fans; closed symbols: mean \(N_b\) of the measured fans. Error bars represent range of \(N_b\) values for 6 smaller sections of each contour of the measured fans and 2 smaller sections for each field fan.