Assessment of landslide risk in the mountainous area. Case study: Bumiaji Sub-District

Abstract

Throughout 2016-2021, there were 31 landslides that have caused physical, economic, and social damages. Bumiaji Sub-District has several tourist destinations that are potentially exposed to landslides. This study aims to create a landslide risk map in Bumiaji Sub-District. This research was conducted during the COVID-19 pandemic situation. Therefore, the data collected was secondary data obtained from Google satellite images, Google Street View, the digital elevation model from the National Geospatial Institution, and other literature reviews. The data was then analysed using a landslide risk assessment based on Perka BNPB Number 2/2012. The results of this risk analysis show that Bumiaji Sub-District is dominated by low-level risk (48%), followed by high-level risk (30%), and medium-level risk (15%). High-risk level is affected by high hazards and vulnerabilities, especially in Giripurno Village. High hazard level is affected by high intensity of rainfall, slope degree, the sensitivity of soil to erosion, and the type of land cover. High vulnerabilities are affected by physical, social, and economic aspects susceptible to losses.

A Multicriteria Approach to Assessing Landslide Community Resilience. Case Study: Bumiaji Sub-District

“…where: ƛ 𝑚𝑎𝑥 : Average of formula 3 n : number of elements 𝐶𝑅 = 𝐶𝐼 𝑅𝐼−1 (5) where: CR : Consistency ratio RI : Random index, based on Table 3. CI : Consistency ratio Standardized data using Z-Score.…”

“…Gunungsari has the lowest score in environmental aspects, caused by the low ratio of protected forests. This condition causes a high landslide risk in 51% of the total area [5]. In February 2021, an enormous landslide occurred in Gunungsari Village, causing physical damage.…”

“…This Village has the high-scores in environmental and community capital (Figure 2). Sumber Brantas is dominated by protected forests (79% of the total area) [5]. The availability of protected forests reduces landslide risk in Sumberbrantas.…”

“…Bumiaji Sub-District is located in the mountainous area with a high-risk level of landslides caused by high hazards and vulnerability [5]. The land-use conversion from protected forest to agriculture in Sub-Brantas Upstream affected the high frequency of landslide events [6].…”

“…Studies on disaster resilience are increasing, but research focusing on landslide resilience is lacking [8]. Previous landslide research in Bumiaji still focuses on hazard or risk analysis [5,7,9,10]. There has been no specific research on landslide resilience, although disaster-resilient village programs have been introduced in every village.…”