Estimating nonlinear source parameters of volcano deformation: an application of FEM-based inverse methods and InSAR

Show simple item record

dc.contributor Goodliffe, Andrew M.
dc.contributor Hansen, Samantha E.
dc.contributor Han, Luoheng
dc.contributor.advisor Masterlark, Timothy
dc.contributor.author Stone, Jonathan
dc.date.accessioned 2017-03-01T14:48:46Z
dc.date.available 2017-03-01T14:48:46Z
dc.date.issued 2011
dc.identifier.other u0015_0000001_0000734
dc.identifier.other Stone_alatus_0004M_10816
dc.identifier.uri https://ir.ua.edu/handle/123456789/1239
dc.description Electronic Thesis or Dissertation
dc.description.abstract Migration of magma within an active volcano produces a deformation signature at the Earth's surface. The internal structure of a volcano and specific movements of the magma control the actual deformation that is observed. Relatively simple models that simulate magma injection as a pressurized body embedded in a homogeneous elastic half-space (e.g., Mogi) can predict the characteristic radially-symmetric deformation patterns that are commonly observed for episodes of volcano inflation or deflation. Inverse methods, based on half-space models, can precisely and efficiently estimate the non-linear parameters that describe the geometry (position and shape) of the deformation source, as well as the linear parameter that describes the strength (pressure) of the deformation source. However, although such models can accurately predict the observed deformation, actual volcanoes have internal structures that are not compatible with the elastic half-space assumptions inherent to Mogi-type models. This incompatibility translates to errors in source parameter estimations. Alternatively, Finite Element Models (FEMs) can simulate a pressurized body embedded in a problem domain having an arbitrary distribution of material properties that better corresponds to the internal structure of an active volcano. FEMs can be used in inverse methods for estimating linear deformation source parameters, such as the source pressure. However, perturbations of the non-linear parameters that describe the geometry of the source require automated re-meshing of the problem domain - a significant obstacle to implementing FEM-based nonlinear inverse methods in volcano deformation studies. I present a parametric executable (C++ source code), which automatically generates FEMs that simulate a pressurized ellipsoid embedded in an axisymmetric problem domain, having an a priori distribution of material properties. I demonstrate this executable by analyzing Interferometric Synthetic Aperture Radar (InSAR) deformation data of the 1997 eruption of Okmok Volcano, Alaska as an example. This executable facilitates an inverse analysis that estimates the non-linear parameters that describe the depth and radius of the spherical source, as well as the linear strength parameter that best accounts for the InSAR data. The strong radial symmetry and high signal-to-noise ratio of the InSAR data, along with known seismic tomography data, provide robust constraints for estimated parameters and sensitivity analyses.
dc.format.extent 52 p.
dc.format.medium electronic
dc.format.mimetype application/pdf
dc.language English
dc.language.iso en_US
dc.publisher University of Alabama Libraries
dc.relation.ispartof The University of Alabama Electronic Theses and Dissertations
dc.relation.ispartof The University of Alabama Libraries Digital Collections
dc.relation.hasversion born digital
dc.rights All rights reserved by the author unless otherwise indicated.
dc.subject.other Geophysics
dc.subject.other Geology
dc.subject.other Geographic information science and geodesy
dc.title Estimating nonlinear source parameters of volcano deformation: an application of FEM-based inverse methods and InSAR
dc.type thesis
dc.type text
etdms.degree.department University of Alabama. Dept. of Geological Sciencess
etdms.degree.discipline Geology
etdms.degree.grantor The University of Alabama
etdms.degree.level master's
etdms.degree.name M.S.


Files in this item

This item appears in the following Collection(s)

Show simple item record

Search DSpace


Browse

My Account