LAHAR MODELING OF MT. AGUNG 1963-1964 AND 2017-2018 ERUPTIONS USING THREE DEM DATASETS: TERRASAR-X, SRTM 1-ARC GLOBAL, AND DTM DERIVED FROM INDONESIAN TOPOGRAPHIC MAP 1:25,000

• Main Author: Gede Dalem Elang Erlangga - Nim: 15114023, I
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/27922
• Institution: Institut Teknologi Bandung

<p align="justify">Lahar is a secondary hazard of volcanic eruption which was formed when unconsolidated or loose volcanic materials mixed with water flowing down the volcano slopes at relatively high velocity. Since 1500 AD, at least lahars claimed 56,315 victims, or about 26 % of all volcanic eruption fatalities (Brown et al; 2017). When erupted in 1963, rain-triggered lahar from Mt. Agung claimed around 200 fatalities in Subagan village alone. Lahar hazard zone assesment is highly needed and important in mitigation purposes espescially when Mt. Agung begin to reactivate in the late 2017. Lahar hazard zone will be assesed with LAHARZ modelling methods, using three DEM inputs: DTM derived from Indonesian topographic map, SRTM 1-Arc Second Global, and TerraSAR-X DSM datasets. Planimetric and cross sectional area of lahar inundation zone was modelled according to the given volumes parameter. The modelling results indicates that the usage of those three different DEMs data has it is own advantages and disadvantages. DTM from topographic map and SRTM 1-Arc Second Global are not good enough when used in wide flat area such as in northen and southwestern sector of Mt Agung volcano due to their relatively low vertical accuracy. While SRTM data will generalize the stream drainage with it is low spatial resolution. Lahar volume estimation is succesfully done using the reversed Iverson (1998) empirical formulas. The estimated lahar total volumes 1963-1964 eruption is around 53.4 x 106 m3, and lahar volumes from 2017-2018 eruption was estimated around 3.5 x 106 m3.<p align="justify">