In this thesis a depth-averaged model in a terrain-fitted coordinate system is applied to simulate the pyroclastic flows during the eruption of Mt Merapi in 2010 Through the numerical simulation we are able to obtain more precise flow information such as the local flow fluxes the distributions of flow depth and velocity as well as the deposits for the goal of hazard mitigation or hazard management In the numerical computation the terrain-fitted coordinate system is based on the digital elevation model (DEM) Because of the fact that the real topography might consists of highly varying elevation e g obstacles or cliffs which is not applicable in the terrain-fitted coordinate a compromised treatment is to smooth (filter) the topographic surface However the employment of the smooth basal surface might introduce deviation because of the lack of the sudden change of topography In this study we introduce the so-call “sub-topography” over the smoothed topographic surface to mimic the real topography In the simulations we also introduce the “Upwelling” to mimic the exploded material especially by the multiple eruptions so that we may have a more reasonable spreading/supply of flow material In addition we also investigate the impacts of the key parameters on the flow behaviors such as the friction coefficient momentum correction factor and the amount of upwelling Besides the Voellmy rheology has also been taken into account The results of these tests were compared to theoretical findings of rheological analysis presented in previous studies as well as historical records and satellite images to figure out the representative values of the relevant parameters
An application of a depth-averaged model in terrain-fitted coordinate system for pyroclastic flows: a case study of Merapi Volcano eruption 2010 Indonesia
子綺, 倪. (Author). 2017 2月 14
學生論文: Master's Thesis