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Determining rainfall thresholds for landslide initiation A case study in wadaslintang watershed Wonosobo, central java province

Allo, Emba Tampang (2010) Determining rainfall thresholds for landslide initiation A case study in wadaslintang watershed Wonosobo, central java province.

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Abstract:Landsliding is one of the most damaging natural disasters in tropical countries, such as Indonesia, especially on the mountainous and hilly terrain area. The study area, Wadas Lintang Watershed in Wonosobo District, experiences landslide in yearly basis. Due to landslide, the area has been facing the loss of human lives and damages to properties. The landslide events commonly occur in rainy season, thus the rainfall can be regarded as the main trigger in the area. The condition has been being problematic due to lack of availability of information pertaining correlation between rainfall and persistent landslide events in this area. This research intends to determine rainfall thresholds for landslide initiation in the Wonosobo area. The result suggests that the initiation of landslide events in the study area is governed by formula of I = 63.683D-0.336 where I: rainfall intensity (mm); and D: rainfall duration (days). Furthermore, the research indicates that rainfall events up to five days prior to the day of failure also influence slope stability leading to landsliding in the study area, and the recurrence of excessive rainfall event causing landsliding ranges from 1 to 2.42 years. To get better understanding about the landslide initiation in the study area, terrain hydrological assessment also was conducted comprising infiltration rate measurement, soil texture and permeability analysis. The result shows that infiltration capacity is categorized as low to medium indicating that the area is prone to landslide. This is due to presence of highly clay content (30-70%) in the soil material throughout the study area. Slope stability assessment also has been performed using SINMAP analysis. The result reveals the degree of susceptibility of the area to landsliding that 66.76% of the total area categorized as stable, 9.14% as low susceptible, 9.91% as medium susceptible, 12.34% as high susceptible, and 1.86% as very high susceptible. The result cannot be verified due to limited data; however it can be used as preliminary tool for identification of hazardous and safe area in this study area. Keywords: landslide, rainfall thresholds, infiltration, slope stability, SINMAP.
Item Type:Essay (Master)
Faculty:ITC: Faculty of Geo-information Science and Earth Observation
Programme:Geoinformation Science and Earth Observation MSc (75014)
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