HR: 17:00h
AN: GP14A-04    [Abstracts]
TI: Development of Nested Modeling in the Modular Electromagnetic Modeling and Inversion Software (MEMIS) System: A New Software Tool for EARTHSCOPE
AU: * Tandon, K
EM: kush@coas.oregonstate.edu
AF: College of Oceanic and Atmosheric Sciences, Oregon State University, COAS Admin. Bldg. 104, Corvallis, OR 97331 United States
AU: Egbert, G D
EM: egbert@coas.oregonstate.edu
AF: College of Oceanic and Atmosheric Sciences, Oregon State University, COAS Admin. Bldg. 104, Corvallis, OR 97331 United States
AU: Siripunvaraporn, W
EM: scwp@mahidol.ac.th
AF: Mahidol University, Department of Physics, Faculty of Science Rama 6 Rd., Bangkok, 104000 Thailand
AB: We are developing modular electromagnetic (EM) modeling and inversion software (MEMIS) as a tool for novel modeling and hypothesis testing, and for prototyping inversion algorithms for electromagnetic data. Flexibility in the design facilitates incorporating new approaches to modeling in geologically complex, multi-scale environments. As an illustrative example we consider development of a nested modeling capability, with boundary conditions for a smaller target area determined from a regional scale geoelectrical model solution. In addition to providing more realistic boundary conditions, our approach allows quantitative assessment of the sensitivity of data to uncertainties in large-scale boundary conditions. This nested approach to EM data interpretation will allow information about the continental scale geoelectric environment obtained from the EARTHSCOPE big-foot magnetotelluric (MT) array to be integrated into interpretations of higher resolution local surveys. As an initial test example, we consider MT imaging of the San Andreas Fault in the vicinity of SAFOD at Parkfield (California), an area where both high resolution and larger scale MT surveys have been conducted, or are being planned. Through forward modeling exercises we explore the interaction of far-field features, such as electrical currents induced in the Pacific Ocean, with the local three-dimensional fault structure. Data sensitivities are used as an initial assessment of the potential impact of improved regional scale models on interpretation of high-resolution MT surveys in the vicinity of SAFOD. A long-term goal is to evolve MEMIS into a flexible, extensible open source system for EM modeling and inversion that will allow the broader earth science community to make better use of the multi-scale EM datasets expected to be collected through national and international programs, such as EARTHSCOPE.
DE: 3210 Modeling
DE: 0619 Electromagnetic theory
DE: 0639 Nonlinear electromagnetics
DE: 0644 Numerical methods
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2004 AGU Fall Meeting