Solid modeling techniques to build 3D finite element models of volcanic systems: An example from the Rabaul Caldera system, Papua New Guinea

  • Authors:
  • Erika Ronchin;Timothy Masterlark;Joan Martí Molist;Steve Saunders;Wei Tao

  • Affiliations:
  • Grupo de Volcanología de Barcelona (GVB-CSIC), SIMGEO (UB-CSIC), Institute of Earth Sciences Jaume Almera (CSIC), Lluís Solé Sabarís s/n, Barcelona 08028, Spain and Department ...;Department of Geological Sciences, The University of Alabama, Tuscaloosa, Alabama 35487, USA;Grupo de Volcanología de Barcelona (GVB-CSIC), SIMGEO (UB-CSIC), Institute of Earth Sciences Jaume Almera (CSIC), Lluís Solé Sabarís s/n, Barcelona 08028, Spain;Rabaul Volcano Observatory, P.O. Box 386, Rabaul, East New Britain Province, Papua New Guinea;State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Beijing 100029, China

  • Venue:
  • Computers & Geosciences
  • Year:
  • 2013

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Abstract

Simulating the deformation of active volcanoes is challenging due to inherent mechanical complexities associated with heterogeneous distributions of rheologic properties and irregular geometries associated with the topography and bathymetry. From geologic and tomographic studies we know that geologic bodies naturally have complex 3D shapes. Finite element models (FEMs) are capable of simulating the pressurization of magma intrusions into mechanical domains with arbitrary geometric and geologic complexity. We construct FEMs comprising pressurization (due to magma intrusion) within an assemblage of 3D parts having common mechanical properties for Rabaul Caldera, Papua New Guinea. We use information of material properties distributed on discrete points mainly deduced from topography, geology, seismicity, and tomography of Rabaul Caldera to first create contours of each part and successively to generate each 3D part shape by lofting the volume through the contours. The implementation of Abaqus CAE with Python scripts allows for automated execution of hundreds of commands necessary for the construction of the parts having substantial geometric complexity. The lofted solids are then assembled to form the composite model of Rabaul Caldera, having a geometrically complex loading configuration and distribution of rheologic properties. Comparison between predicted and observed deformation led us to identify multiple deformation sources (0.74MPa change in pressure in the magma chamber and 0.17m slip along the ring fault) responsible for the displacements measured at Matupit Island between August 1992 and August 1993.