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The Indonesian government recently launched several strategic construction projects in the West Java Province involving the construction of the Kertajati international airport, Jatigede large dam, and Cisumdawu toll road, and upgrading many existing roads and the construction of new ones. It should be noted that some of these projects lie on clay-bearing sedimentary rocks known as Subang claystone, in which many cuts and fills must be constructed. It is already widely known that Subang claystone has unfavorable engineering characteristics regarding slakeability and swellability behaviors, so this research will be helpful to give engineering considerations for all those strategic construction projects. This research will be focused on the analyses of slakeability and swellability characterizations utilizing slake-durability and unconfined swelling tests, as well as consistency analyses of the claystone as standardized by the International Society for Rock Mechanics, Suggested Methods. Field observation and rock samples conducted in the Sumedang area for the claystone is the most abundant rock type. Widespread outcrops, numerous excavations, and road cuts have provided excellent samples. The test results indicated that the claystone could be classified as a very low-durability rock, with Id2 ranging from 5.82% to 26.80%. It means that Subang claystone has a high slakeability characteristic. The claystone also showed a high swellability characteristic with volumetric swelling strain reaching up to 29.6% and medium to high plasticity indexes ranging from 30.9% to 35.2%. There was a good correlation between the claystone's slakeability, swellability, and consistency. [ABSTRACT FROM AUTHOR]

Sumatra Fault as product from tectonic events in Sumatra is the boundary between west and east blocks. Sumatra Fault reactivation could be generated several hazards, especially in Bukit Barisan Selatan National Park (BBSNP). Morphology of Sumatra Fault dominated by hill pattern variations from hill shade form, which should be delineated. The hazard potential has been identified by fault fracture density method combine with geological map and earthquake map. This research used ASTER GDEM and Regional Geology Map as basic data. Lineament interpretation is carried out on drainage map, DEM, and structural geology map. Earthquake data refer by earthquake history occurred near Sumatra Fault and subduction zone in western of Sumatra Island. The earthquake from Sumatra Fault potentially triggers landslide and liquefaction around BBSNP area. There is three regions as having geological hazard potential by Sumatra Fault movement, namely earthquake, landslide and liquefaction. Landslide will be collapsed relatively to the south and affected the main road of BBSNP. Furthermore, in eastern part of Sumatra Fault has liquefaction potential in Semaka and Suoh districts. [ABSTRACT FROM AUTHOR]

Landslide, which is one of the natural disasters that occurs frequently, often causes very adverse effects. Landslide early warning systems, which are installed at prone areas, measure physical parameters closely related to landslides and give warning signals indicating that landslides would occur. To determine the critical values of the measured physical parameters or test the early warning system itself, a laboratory scale model of a rotational landslide was developed. This rotational landslide model had a size of 250×45×40 cm3 and was equipped with soil moisture sensors, accelerometers, and automated measurement system. The soil moisture sensors were used to determine the water content in soil sample. The accelerometers were employed to detect movements in x-, y-, and z-direction. Therefore, the flow and rotational landslides were expected to be modeled and characterized. The developed landslide model could be used to evaluate the effects of slope, soil type, and water seepage on the incidence of landslides. The present experiment showed that the model can show the occurrence of landslides. The presence of water seepage made the slope crack. As the time went by, the crack became bigger. After evaluating the obtained characteristics, the occurred landslide was the flow type. This landslide occurred when the soil sample was in a saturated condition with water. The soil movements in x-, y-, and z-direction were also observed. Further experiments should be performed to realize the rotational landslide. [ABSTRACT FROM AUTHOR]

Gulf of Jakarta is an area of active sedimentation. There exist a wide sediment deposition area on the north coast of Jakarta. Generally, these sediments have not been consolidated, so that the conditions in these area is an important factor to determining liquefaction in these area. Liquefaction may occur because of earthquake that cause loss of strength and stiffness in soils. Analysis of liquefaction potential based from SPT data taken at gulf of Jakarta, include susceptibility rate and the factors that triggering. Liquefaction analysis methods compared with each other to get the factor of safety against liquefaction according to the characteristics of the soil. Liquefaction analysis at surface using susceptibility rating factor (SRF). SRF method controled by factors: history, geology, composition, and groundwater. Each factors have parameters that determine the value of SRF.From the analysis. Gulf of Jakarta has susceptibility rating from liquefaction with SRF value 12 - 35. The value shows that Gulf of Jakarta dominated by area that have susceptibility rating from medium to high. High susceptibility rating from liquefaction concentrated at coast area. [ABSTRACT FROM AUTHOR]