HR: 0830h
AN: V51J-0402    [PDF]
TI: Thickness distribution of a cooling pyroclastic flow deposit: Optimization using InSAR, FEMs, and an adaptive mesh algorithm
AU: * Masterlark, T
EM: masterlark@usgs.gov
AF: USGS/EROS Data Center, 47914 252nd St., Sioux Falls, SD 57198 United States
AU: Lu, Z
EM: lu@usgs.gov
AF: USGS/EROS Data Center, 47914 252nd St., Sioux Falls, SD 57198 United States
AU: Rykhus, R
EM: rykhus@usgs.gov
AF: USGS/EROS Data Center, 47914 252nd St., Sioux Falls, SD 57198 United States
AB: We construct finite element models (FEMs) of a pyroclastic flow deposit (PFD) emplaced during the 1986 eruption of Augustine volcano, Alaska. Interferometric synthetic aperture radar (InSAR) imagery documents the consistent contraction of the PFD during 1992-2000. Three-dimensional problem domains of the FEMs include an elastic substrate overlain by a thermoelastic material representing the PFD. The geometry of the substrate is determined from a digital elevation model (DEM) and bathymetry data. The thickness of the PFD is initially determined from the difference between post- and pre-eruptive DEMs. Systematic prediction errors suggest the PFD thickness distribution, estimated from the DEM difference, is inaccurate. We combine InSAR images, FEMs, and an adaptive mesh algorithm to re-estimate the geometry of the PFD and optimize the thickness distribution for the PFD. Prediction errors from the FEM that includes an optimized PFD geometry are reduced by 20% with respect to those from an FEM that includes a PFD geometry derived from the DEM difference.
DE: 3230 Numerical solutions
DE: 6924 Interferometry
DE: 6969 Remote sensing
DE: 8404 Ash deposits
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2003 Fall Meeting