Determining the Level of Vulnerability to Landslides in Banyubiru Sub-District of Semarang Regency, Central Java, Indonesia

Based on historical record, Semarang Regency in Central Java, Indonesia frequently experiences landslides. Therefore, this study was conducted in Banyubiru Sub District, Semarang Regency, Central Java. The purpose of this study is to determine the variation of field vulnerability to lanslides in the Sub District and also to establish the efforts that must be made to reduce vulnerability in order to decrease losses during the occurance of landslides. Vulnerability includes physical, social, economic and environmental variables. Each region has varying levels, types and characteristics of vulnerability. So as to be refined, the original three classes of the vulnerability index criteria were modified into five criteria i.e. very low vulnerability index criterion (1.00-<1.40), low vulnerability index (1.40-<1.80), moderate vulnerability index (1.80<2.20), high vulnerability index (2.20-<2.40) and very high vulnerability index (2,40-< = 3,0). The results show that the vulnerability level of landslide is divided into 2 parts according to vulnerability indicators in Perka BNPB No.2/2012. Banyubiru sub-district has a moderate and high level of vulnerability. The average of vulnerability rate belongs to the moderate category with an index value of 2,17. The lowest rate is owned by Rowoboni Village while Sepakung village has the highest vulnerability.