The Effect of Rainfall Intensity to Landslide Run-Out Prediction and Velocity: A Parametric Study on Landslide Zones in West Java-Indonesia

Abstract

Assessment and management of landslide risk require the knowledge of landslide run-out distance and velocity. However, the landslide volume as the basis for calculating landslide run-out distance and velocity is governed by slip surface development during rainfall. Thus, it is necessary to understand how rainfall characteristics influence landslide run-out and velocity. This paper presents a parametric study to clarify the effect of rainfall intensity on landslide run-out and velocity of two steep volcanic cut-hillslopes in West Java, Indonesia. The landslide volumes were estimated from the potential sliding surface obtained from slope stability analysis under a rainfall infiltration. The landslide run-out and velocity were then calculated using an energy conservation formula in a lumped mass model. This study shows that the slip surface developed at a different depth in each slope, depending on the rainfall intensity. As a result, the landslide run-out and velocity of both cut-hillslope are significantly different and, in general, decrease to reach a constant value with increasing rainfall intensity. Thus, the results of this study can be used as a guideline to assess the rainfall-induced landslide movement, especially in cut-hillslopes.