## 5 Discussion  
### Geologic Hazards Development in the Earthquake Triggered Hazard Areas  
A study by [PERSON] _et al._[45] showed that earthquakes (including aftershocks) and heavy rainfall were powerful causes of landslide hazards, and earthquake-induced landslides and rainfall-induced landslides could couple to form a disaster chain. A record from the Sichuan Earthquake Networks Center showed that, after the Wenchuan earthquake and up until June 2011, 88,000 aftershocks surrounding the Longmenshan fault were detected, among which more than 400 aftershocks were larger than \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**No.**} & \multicolumn{3}{c}{**Area of Vegetation Recovery (ha)**} & \multicolumn{3}{c}{**Rate of Vegetation Recovery (per year)**} \\ \cline{2-7}  & **2008–2009** & **2009–2011** & **2008–2011** & **2008–2009** & **2009–2011** & **2008–2011** \\ \hline
1 & 51.09 & 46.89 & 83.74 & 0.20 & 0.10 & 0.11 \\
2 & 153.14 & 381.54 & 412.53 & 0.24 & 0.30 & 0.22 \\
3 & 15.23 & 44.17 & 44.99 & 0.13 & 0.18 & 0.12 \\
4 & 42.39 & 33.39 & 67.09 & 0.37 & 0.19 & 0.20 \\
5 & 43.00 & 48.37 & 73.67 & 0.29 & 0.19 & 0.17 \\
6 & 11.98 & 8.81 & 13.50 & 0.25 & 0.10 & 0.09 \\
7 & 209.89 & 189.26 & 399.16 & 0.32 & 0.21 & 0.20 \\
8 & 49.55 & 139.20 & 170.99 & 0.08 & 0.12 & 0.09 \\
9 & 10.71 & 4.70 & 11.71 & 0.10 & 0.02 & 0.04 \\
10 & 55.05 & 211.02 & 198.52 & 0.11 & 0.20 & 0.14 \\
11 & 23.94 & 53.73 & 65.51 & 0.15 & 0.16 & 0.14 \\
12 & 36.12 & 50.71 & 79.56 & 0.19 & 0.16 & 0.14 \\
13 & 155.09 & 12.57 & 164.54 & 0.41 & 0.03 & 0.15 \\
14 & 8.30 (2008–2010) & 3.13 (2010–2011) & 2.67 (2008–2011) & 0.03 (2008–2010) & 0.02 (2010–2011) & 0.01 (2008–2011) \\
15 & 7.16 (2009–2010) & 33.53 (2010–2011) & 38.41 (2009–2011) & 0.01 (2009–2010) & 0.03 (2010–2011) & 0.02 (2009–2011) \\ \hline Total & 857.18 & 1224.36 & 1785.51 & 0.22 & 0.18 & 0.15 \\ \hline \hline \end{tabular} Note: The “Total” row is the accumulation of the first thirteen hazards sites and does not include the last two. The years in the bracket of site No. 14 and No. 15 refers to the start and end years of variation.  
\end{table} 
Table 5: Area and rate of vegetation recovery on previously bare landslide masses. Figure 7: Comparison of hazard development rates from 2008 to 2011. 4.0 magnitude [46], and the occurrence of aftershocks was especially intense in the northeastern segment of the fault, which had some connection with the increased stress in this region [47]. Meanwhile, heavy rainfall occurred on 23 and 24 September 2008, reaching 250-350 mm and triggering new landslides and active old landslides, causing debris flow hazards to occur in groups [45]. Considering the four geologic hazard cases examined in Section 4.1 of this paper, the first case is relatively stable-aftershocks and heavy rainfall had little influence on the landslide mass, so the vegetation growth rate was faster than the hazard increase rate. For the second case, the geologic hazard variation is in accordance with the distribution of aftershocks and heavy rainfall. A study from [PERSON] _et al._[48] also showed that the aftershocks along the Longmenshan fault happened mainly within one year after the earthquake (Figure 8), and geodynamics and spatial pattern of vegetation damage was affected by rupture zones [49]. For the third and fourth cases, the geologic hazards are unstable, and the debris flow development of these two cases is consistent with human activity. For example, the anomalous variation of No. 9 and No. 14 sites was related to the Changheba Dam construction. Considering the whole hazard area, the recovery of hazards was comparatively slow in the first year after the earthquake, when the area suffered the most intense aftershocks and heavy rainfalls. The rate was 11.6%, less than the average speed of recovery. After 2009, slopes became more stable and the vegetation on the landslides recovered rapidly, with an annual recovery rate of 12%.