In the Parangtritis Beach tourism area located in the Southern Mountain of Yogyakarta, karst hills were excavated to build the main accessing road and produce some of long and very steep slopes along the sides of the road. But still, there was none of the slope reinforcement installed along the road. Meanwhile, at several nearby locations within Southern Mountain, rockfall incidents have occurred many times even caused casualties. The potential of rockfall hazard also could be found in the main road of Parangtritis Beach as the study area. The purpose of this study is to determine the rockfall hazard assessment along the main road using Slope Mass Rating (SMR) analysis with the additional parameter of the slope height and the rock block size. The necessary data obtained by direct measurement and laboratory test. Geomechanics analysis, stereographic projection analysis, and hazard parameters weighting were carried out to produce the Rockfall Hazard Zonation Map of the study area. Based on 17 measurement stations, there are 4 (four) rockfall hazard classes in the study area, i.e., very low, low, moderate, and high. The class of very low, which also included road segments without slope, has the largest percentages of 83.83%, followed by the classes of moderate, low, and high with the percentage of 7.16%, 4.28%, and 4,19%, respectively. SMR was assumed as the most significant parameter that influences the rockfall hazard zonation. Historical rockfall points were overlaid over the Rockfall Hazard Zonation Map to validate the predicted hazard zones. Since 91.23% of the rockfall occurred in the moderate and high hazard classes, the zonation map considered reliable to predict future rockfall. This study also identified several landslide potential zones and provides the recommendation of slope reinforcement to be installed in the study area.

Open-pit mining constitutes a necessary activity for the extraction of rocks and minerals from the Earth. However, openpit mining activities often result in rock slope stability issues related to the discontinuities of rock masses. Thus, an appropriate cut-slope design in open-pit mining requires good knowledge of the effects of discontinuity on rock mass strength and quality. This study aims to analyze the effect of discontinuity type on rock quality and slope stability. Discontinuity data was collected from the columnar jointed-andesite rock slope in West Java. The analysis showed that the examined andesite slope has a good rock mass quality and very favorable slope stability. However, wedge-type slope failure may occur, which is substantially affected by columnar joints present in the rock mass. Moreover, the analysis indicated that the integral discontinuities present in the andesite outcrops significantly affect the mean values of the discontinuity length, discontinuity spacing, and rock strength. However, the integral discontinuities have little effect on the slope mass rating (SMR). Thus, detailed studies on the contribution of integral discontinuities to the rock mass rating and SMR of different rock types are recommended.

West Bandung, West Java, is an area with a high level of landslide susceptibility. Landslides in West Bandung occurred 142 times during rainfall in the last ten years. This paper presents the results of landside susceptibility modeling in the West Bandung area of West Java Province, Indonesia, considering the spatial characteristics of the rainfall data, slope and soil properties using the TRIGRS model. This research is based on conditions in the field in the form of landslide locations, soil engineering properties, soil thickness, Digital Elevation Model, and rainfall data. The effect of one-day antecedent rainfall intensity was considered in this study, i.e., 12 hours of antecedent rainfall. The results of the TRIGRS modelling showed that the intensity of rainfall antecedent of rainfall influenced the slope stability in the study area. The TRIGRS model results indicate that the predicted landslide susceptibility distribution agrees with the historical landslide events.

In the Parangtritis Beach tourism area located in the Southern Mountain of Yogyakarta, karst hills were excavated to build the main accessing road and produce some of long and very steep slopes along the sides of the road. But still, there was none of the slope reinforcement installed along the road. Meanwhile, at several nearby locations within Southern Mountain, rockfall incidents have occurred many times even caused casualties. The potential of rockfall hazard could also occur in the main road of Parangtritis Beach as the study area. The purpose of this study is to determine the rockfall hazard assessment along the main road using Slope Mass Rating (SMR) analysis with the additional parameter of the slope height and the rock block size. The necessary data obtained by direct measurement and laboratory test. Geomechanics analysis, stereographic projection analysis, and hazard parameters weighting were carried out to produce the Rockfall Hazard Zonation Map of the study area. Based on 17 measurement stations, there are 4 (four) rockfall hazard classes in the study area, i.e. very low, low, intermediate, and high. The very low class, which also included road segments without slope, has the largest percentage of 83.83%, followed by the classes of intermediate, low, and high with the percentage of 7.16%, 4.28%, and 4,19%, respectively. SMR was assumed as the most significant parameter that influences the rockfall hazard zonation. To validate the predicted hazard zones, historical rockfall points were overlaid over the Rockfall Hazard Zonation Map. Since 91.23% of the rockfall occurred in the intermediate and high hazard classes, the zonation can be considered reliable to predict future rockfall. This study also identified several landslide potential zones and provides the recommendation of slope reinforcement to be installed in the study area.

During the 28 September 2018 Palu-Donggala earthquake, liquefaction was also a prominent hazard causing significant damage to buildings and infrastructures in Palu City. To mitigate such a hazard in Palu City, knowledge of the depth of the liquified soil layer is necessary. This paper presents the results of CPT-based liquefaction potential analysis in some locations around the city where sand boiling and ground settlement occurred. The analysis shows that liquefaction occurs at various depths less than 15 m and may induce ground settlement up a few centimeters. In the Palu-Koro Fault zone, the liquified sand layer is likely thicker than in other locations. Consequently, the total ground settlement is higher than in other locations The results of this study suggest that the liquefaction potential should be accounted for in the development of Palu City to reduce future earthquake risk.