Landslide Hazard Mitigation for Sustainability Settlement in Maninjau Lake Geopark, West Sumatera Iqbal E. Putra (a,b*), Kibar M. Suryadana (b), Dian Hadiyansyah (c)
a) Magister Program in Regional and City Planning, School of Architecture, Planning and Policy Development, Institut Teknologi Bandung (ITB)
*iqbalputra87[at]gmail.com
b) Center of Volcanology and Geological Hazard Mitigation, Geological Agency, Ministry of Energy and Mineral Resources
c) Department of Energy and Mineral Resources, West Sumatera Province
Abstract
The landslide around the Maninjau Caldera rim, particularly in the south, have posed a significant threat to lives over the years. Settlements nestled between Maninjau Lake and the caldera wall are highly vulnerable to these hazards, and relocation is not feasible due to the scarcity of suitable land. Identifying the safest area based on historical landslide data is crucial for mitigation works in developing Ngarai Sianok-Maninjau Geopark. The most recent major landslide occurred on July 13, 2023, in the Tanjung Raya District following heavy rainfall. The western and southern section of the caldera rim, characterized by the steepest slopes are most prone to landslides. There are approximately 43 landslides with debris flow mechanisms along the inner caldera rim covering 3 villages (nagari), namely Koto Malintang, Tanjung Sani, and Sungai Batang. Landslide debris in the southeast consist mainly of muddy sand, contrasting with the gravel and boulder sediment found elsewhere. All landslides originate in intermittent streams, creating sediment fans up to 50 meters wide downstream. Given this fan-shaped pattern, dispersed residential development is advisable over clustered housing, especially in Jorong Pantas, Tanjungsani Village. The high susceptibility of all drainage channels to landslide makes the main road vulnerable to disruption. Water transportation is strongly recommended as an alternative to prevent residents from becoming isolated if the main road is blocked.
Keywords: Caldera, Landslide, Maninjau Lake, Sediment Fan
