HR: 1400h
AN: V23A-14    [Abstracts]
TI: DEM Data for Lahar Modeling: Lahars From Popocatépetl Volcano (Mexico)
AU: Huggel, C
EM: chuggel@geo.unizh.ch
AF: Glaciology and Geomorphodynamics Group, Department of Geography, University of Zurich, Winterthurerstr. 190, Zurich, 8057, Switzerland
AU: Schneider, D
EM: dschneid@geo.unizh.ch
AF: Glaciology and Geomorphodynamics Group, Department of Geography, University of Zurich, Winterthurerstr. 190, Zurich, 8057, Switzerland
AU: * Julio-Miranda, P
AF: Cuerpo Académico de Ciencias Sociales, CCSyH, Universidad Autónoma de San Luis Potosi, Av. Industrias 101-A, SLP, SLP 78494, Mexico
AU: Delgado-Granados, H
EM: hugo@geofisica.unam.mx
AF: Instituto de Geofísica, Universidad Nacional Autónoma de México, C.U., Coyoacán, Mexico, DF 04510, Mexico
AU: Kääb, A
EM: andreas.kaab@geo.uio.no
AF: Department of Geosciences University of Oslo, Postbox 1047, Oslo, 0316, Norway
AB: Modeling of lahars has become important for related hazards assessment, particularly in regions with scarce geologic record. Digital terrain data is a crucial element for mass-flow modeling but limited by availability of DEM's. Remote sensing technology offers perspectives for DEM generation. DEMs derived from ASTER stereo satellite images and SRTM from Popocatépetl Volcano, taken on 2001, were evaluated using two simple, non-dynamic lahar models LAHARZ and MSF. Laharic volumes were based on the 1995-2001 events. Results of model runs for the Huiloac gorge based on the ASTER-DEM show that only lahars with a volume of 5x106 m3 or larger reach towns 11km away. Lahars modeled with SRTM-DEM travel 1.8 km further downstream. The ASTER-based model tends to a stronger lateral distribution of the flow volume, thus limiting the longitudinal distribution. In comparison to the observed lahar of corresponding volume in 1997, the modeled lahars fit in travel distance by ca. 2 and 4 km for SRTM and ASTER, respectively. The flow paths for the ASTER and SRTM DEMs are consistent except for the middle section where an erroneous flow-routing of the ASTER model can be observed, caused by an error of the respective DEM. ASTER and SRTM DEMs, are suitable for use with LAHARZ and MSF. Flow path prediction is more reliable with SRTM data but with coarser spatial resolution. Errors of the ASTER DEM affecting the prediction of flow paths are mainly identified in deeply incised gorges with north-facing slopes due to the sensor geometry. LAHARZ is more sensitive to errors of the ASTER DEM than the MSF model. Lahar modeling with the ASTER-DEM results in a finer spaced predicted inundation area but does not add any significant information in comparison with the SRTM DEM. The verification and sensitivity of the DEM used is fundamental when deriving hazards maps to forecast inundation areas.
DE: 8485 Remote sensing of volcanoes
DE: 8488 Volcanic hazards and risks
SC: Volcanology, Geochemistry, and Petrology [V]
MN: 2007 Joint Assembly