Lahar flow characteristic of Semeru Volcano based on Flow-R Model and its countermeasure

Abstract

Lahar flows represent a consequential outcome of volcanic eruptions, posing a natural hazard with the potential to profoundly impact both society and infrastructure. These fast-moving streams of volcanic lahar surge from elevated terrains to lower altitudes, commonly referred to as lahar flows. The Rejali Watershed, nestled in Lumajang Regency, East Java, Indonesia, serves as one of the key watersheds sourced from the elevated slopes of the Semeru Volcano, eventually merging into the Indian Ocean as its outlet. The primary objective of the study is to uncover the distinct characteristics of Semeru Volcano’s lahar flows and suggest feasible countermeasures aimed at averting potential future disasters. A thorough comprehension of the potential dangers associated with lahar flows is imperative in identifying the requisite countermeasures and regulations to be implemented for the purpose of disaster risk reduction. The findings highlight the utility of the model in effectively mapping the impact of the Semeru volcanic eruption. This is achieved through the utilization of back analysis to acquire insights into the characteristics of these lahar-related disasters. While the model exhibits a good correlation with reality, as evidenced by the Sentinel 2 image, it falls short of adequately representing certain specific areas.