Verification of mountain road hazard susceptibility maps - Provincial highway routes 8 and 9 as study area

摘要

In Taiwan, hazard susceptibility maps of the Provincial highway routes 8 and 9 were produced by the Fourth Maintenance office, Directorate General of Highways, and the Ministry of Transportation and Communications (MOTC) in 2014 and 2015. The maps show that there are 235 road sections marked as high-potential hazard locations along route 8. and there are 80, 44, 34, and 7 locations classified as high, moderate, low, and very low-potential hazard locations, respectively, along route 9.Based on the hazard susceptibility maps, we verify and discuss the occurrence of landslides on the two routes using the landslide inventories during 2015-2017. The results show that: (1) at 129 locations along route 8, 314 landslides have occurred, the 158 landslides that have occurred at the other 79 locations are not shown on the hazard susceptibility maps; (2) 256 landslides have occurred along route 9 in the past three years. 181 landslides have occurred at 49 high-potential hazard locations; 26 landslides have occurred at 15 moderate-potential hazard locations; 46 landslides have occurred at 12 low- potential hazard locations; 3 landslides have occurred at 2 very low- potential hazard locations.From the results, we suggest further investigations is required of the hazard susceptibility maps of the Provincial highway routes 8 and 9.