Description

Landslides frequently occur in Indonesia, especially in mountainous areas. A debris flow induced by landslides occurred in two regions in Sumatra, where the authors found that several minor earthquakes in a row and cumulative rainfall could trigger landslides. This study aims to examine the mechanism behind these landslides, identify the most significant contributing factors, and hypothesize the general causes of landslides. Field investigations and soil sampling were conducted for the research. These areas are within the Strike-Slip Fault of the Great Sumatra Fault and its segments, which are tectonically active. The areas are covered with residual soil, and the deeper lithology consists of volcanic rocks. Alteration processes have produced a thick layer of soil from volcanic rocks. The residual soil was analyzed using Wesleys method, revealing that the thick soil layer is dominated by silty clay and minerals. Fault networks, seismicity, and high rainfall intensity (cumulative rainfall) are the dominant factors controlling these landslides. Earthquake observations were monitored using data from the Meteorological, Climatological, and Geophysical Agency of Indonesia / BMKG (https://dataonline.bmkg.go.id/home). The authors propose that, in the future, collaboration with stakeholders, especially the BMKG, which owns rainfall and earthquake data, could enable the sharing of these data. This collaboration could facilitate the application of the proposed method, potentially through the development of an app for landslide prediction, aimed at enhancing public safety (benefit for driver, village people, government officials, companies for road safety and generally for hazard warnings).

Date Conducted

February 2025

Contributors

Wilham LOUHENAPESSY