Experiments on seepage-triggered cliff landslides using cohesive wet sand

Progress in Earth and Planetary Science

Table 2 A summary of the cliff landslide experiments

Run	H (cm)	\(H / H_{\mathrm{max}}\)	L (cm)	H/L	\(\phi\)	S	\(h_{\mathrm{w}}\) (cm)	\(h_{\mathrm{w}} / H\)	Result	Images, movies
1	20.5	0.62	13.5	1.52	0.52	0.31	5.0	0.24	2 slides \(+\) spread	–
2	20.0	0.60	13.5	1.48	0.53	0.30	2.0	0.10	No slide	–
3	20.0	0.60	13.5	1.48	0.51	0.55	3.0	0.15	2 slides	–
4	20.0	0.60	13.5	1.48	0.50	0.39	2.0	0.10	1 slide	Fig. 5
5	19.5	0.59	13.5	1.44	0.50	0.33	10.0	0.51	2 slides \(+\) spread	–
6	20.0	0.60	13.5	1.48	0.51	0.14	6.0	0.30	2 slides \(+\) spread	–
7	20.0	0.60	13.5	1.48	0.51	0.40	15.0	0.75	1 slide \(+\) flooding	Fig. 3a
8	20.0	0.60	13.5	1.48	0.50	0.31	2.0	0.10	No slide	Fig. 4
9	12.5	0.38	13.5	0.93	0.49	0.29	2.0	0.16	1 slide\(^{\dagger }\)	Fig. 8a
10	12.0	0.36	13.5	0.89	0.51	0.36	2.0	0.17	1 slide	–
11	12.0	0.36	13.5	0.89	0.53	0.29	6.0	0.50	3 slides \(+\) spread	–
12	20.0	0.60	13.5	1.48	0.51	0.31	13.0	0.65	1 slide \(+\) flooding	Fig. 7 and Additional file 3: Movie S3
13	20.0	0.60	13.5	1.48	0.51	0.37	1.8	0.09	1 slide	Figs. 3a, 8a and Additional file 1: Movie S1
14	20.0	0.60	13.5	1.48	0.50	0.27	8.0	0.40	2 slides \(+\) spread	Figs. 3a, 6 and Additional file 2: Movie S2
15	16.0	0.48	13.5	1.19	0.50	0.32	2.0	0.13	No slide	–
16	8.0	0.24	13.5	0.59	0.50	0.28	2.0	0.25	3 slides \(+\) spread	–
17	4.0	0.12	13.5	0.30	0.51	0.26	2.0	0.50	1 slide \(+\) spread	Fig. 8a
18	12.6	0.38	8.5	1.48	0.51	0.36	5.7	0.45	3 slides \(+\) spread	–

H: cliff height, \(H_{\mathrm{max}} = 33\) cm is obtained from Eq. (3), L: cliff length. The cliff width W is \(W = 35\) cm
\(\phi\): packing fraction of sand particles. Average ± standard deviation: \(\phi = 0.51 \pm 0.01\)
S: water saturation in pore space. Average ± standard deviation: \(S = 0.32 \pm 0.08\)
\(h_{\mathrm{w}}\): Hydraulic head. \(\dagger\): sensor data acquisition stopped during the run (\(\times\) in Fig. 9a)