Ecology, Environment and Conservation Paper

THE STIPULATION OF HAZARD ZONE DISTRIBUTION OF LANDSLIDE MOVEMENT BASED ON ABOVE EARTH SURFACE PARAMETER AND UNDER EARTH SURFACE PARAMETER USING THE WEIGHTING ANALYTICAL HIERARCHICAL PROCESS IN SETTLEMENT AREA OF TRANGKIL, SEMARANG CITY

Tony Yulianto, Suripin and Hartuti Purnaweni

Abstract

The settlement area of Trangkil in Semarang City located on a steep slope topography that rest on a clay sediment, once had a landslide at the rainfall in early 2014. This area has groundwater level about 7-10 meter depth from the surface and Ground Shear Strain (GSS) more than 10-2 above the slip surface on clay sediment with a resistivity of (32.2-119) &!m. Mapping of the level of landslide hazard in this area is necessary for mitigation planning. Research on the distribution of danger zone with various parameter measured on the earth’s surface such as slope, geology, the use of the land had been conducted a lot, but none was combining comprehensively the parameter of above the earth’s surface and under the earth’s surface like the value of the groundwater level and the value of GSS within the landslide danger distribution. In this study the distribution of parameter value over the earth’s surface and the distribution of the parameter under the surface was overlaid using Analytical Hierarchical Process (AHP) weighting method were done to obtain the distribution of landslide hazard area classification, with the ratio consistency score of 0.028. The results showed that there were four landslide hazard zones, i.e. very low hazard zone, low hazard zone, medium hazard zone, and high hazard zone. The validation result with the slope stability analysis of the Bishop method on the high hazard zone of the landslide had a 1.37 safety factor while in low hazard zone had a 1.77.