Run-out distribution of debris-flow materials: case study from some Java landslides

Abstract

Indonesia is a risk prone country from landslide disasters. The occurrence of landslides followed by the debris flow often make a lot of casualties and very terrible destructions. Accordingly, debris flow modeling of some Java landslides has been conducted in this study to determine run-out distribution characteristics of the debris materials. The concept of debris flow modeling is based on the equations of momentum, continuation, riverbed deformation, erosion/deposition and riverbed shearing stress. From this modeling, it has been indicated the best fit simulation results. In this case, run-out distributions of Pacet landslide at Mojokerto, December 12, 2002 has been properly modeled with a scenario of 0.4 viscosity value for around 5 minutes. At Sijeruk landslide, Banjarnegara, January 4, 2006 run-out distributions have been modeled using viscosity value of 0.45 for 14 minutes 51 seconds. Meanwhile, the modeling for Tenjolaya landslide at southern Bandung, February 23, 2010 with viscosity value of 0.38 shows time needed for debris materials to reach depositional area is estimated for around 12 minutes 37 seconds. From this study, debris flow modeling had given better understandings regarding flow track, velocity and distribution of debris materials from some debris flows in Java.