Geographia Technica, Vol 18, Issue 2, 2023, pp. 68-78
SPATIAL MODEL OF RUNOFF FLOWING INTO THE NEWLY FORMED LAKE AT SINABUNG VOLCANO
Sandy Budi WIBOWO 
, Polin Mouna TOGATOROP, Tsamara HANINDHIYA, Barandi Sapta WIDARTONO , R. Ibnu ROSYADI
ABSTRACT: Volcanic dams are formed when eruptions occur near rivers, obstructing the natural flow of water and creating a dam. The infrequent nature of volcanic dams has resulted in limited research and literature on this topic. However, the Sinabung stratovolcano offers a valuable opportunity to address these knowledge gaps. Over a span of ten years of eruptions, abundant volcanic materials have accumulated in the Lau Borus River, leading to the growth of a dam and the formation of a lake behind it. This research aims to develop a GIS model that simulates the runoff flowing into the newly formed lake at Sinabung volcano. The methodology employed in this study involves the integration of an Agent-Based Model and Geographic Information System to create a dynamic model of runoff and spatio-temporal mapping. The results indicate that raindrops transform into runoff, flowing down the eastern volcanic flank towards the lake, covering a distance of 3.7 km from the crater in 696 seconds, with an average flow velocity of 5.32 m/s. The runoff accumulates in three drainage networks and exhibits two flow pulsations. By combining the Agent-Based Model and Geographic Information System, the research successfully identifies the process of runoff accumulation into the newly formed lake at Sinabung volcano. Further investigation into potential lake outburst scenarios would be crucial for developing comprehensive mitigation strategies for cascading volcanic disasters.
Keywords: Sinabung volcano, runoff, Agent Based Model, GIS, lahars, disasters.
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