Enhanced Assessment of Rainfall and Hydrologic Effects on the Triggering Mechanism of Shallow Landslides

This study presents an approach to enhance the pioneering method for the hydrologic control on shallow landsliding. Although the previous method capable of describing combined effect of rainfall and hydrologic in triggering shallow landslides, it does not consider the effect of hydrological responses in unsaturated layer. Thus the proposed study was intended to enhance the pioneering approach. Accordingly, a coupled grid-based rainfall-runoff model and infinite slope stability approach was simplified. Linking the simplified model with the slope stability approach yields the rainfall threshold for triggering shallow landslides in saturated and unsaturated soils. Finally, coupling this model with the rainfall intensity duration frequency (IDF) can help in understanding the climate control on slope instability. This leads to predict the spatiotemporal scale of the shallow landslide occurrences. Preliminary model application is shown for the Upper Citarum River basin, Indonesia.