Task group Planetary scale Members from LMU Munich
Task group: Planetary scale Members from: LMU Munich IPG Paris INGV Bologna University of Oxford University of Utrecht ETH Zurich University of Oslo Courtesy of J. Woodhouse Mid-Term Review Meeting, February 13 -14, Tutzing www. spice-rtn. org
Key scientific questions The knowledge of the 3 D distribution of temperature and composition is essential to understand the dynamics of our planet. Mantle 2000 2981 km depth Trampert et al. , 2004 • How reliable are our imaging tools ? • How good are our models ? • How important is density, anisotropy and anelasticity for imaging ? Mid-Term Review Meeting, February 13 -14, Tutzing www. spice-rtn. org
Towards some answers During several task group meetings, we identified the following research themes: • Benchmark (reliability of imaging tools) • Database of existing models (quality of models) • Assessment of models using SEM, local modes, full ray theory (quality of models) • Tomographic techniques including data corrections, new inverse techniques and validity of classical forward theories (density, anisotropy, anelasticity) • European reference model (joint with new FP 6 NERIES) and a new global mantle model. Mid-Term Review Meeting, February 13 -14, Tutzing www. spice-rtn. org
The new road The questions and answers are not entirely new, but exiting possibilities for more insight are created by our ability to solve the wave equation numerically in fully 3 D structures on modest Beowulf clusters. Courtesy of H. Igel Mid-Term Review Meeting, February 13 -14, Tutzing www. spice-rtn. org
The benchmark (Ui. O, IPGP) A simple model (dln. Vs) has been made to check the feasibility. Seismograms for the final model (dlnq, dln. Vp, dln. Vs, dlnr, anisotropy, approximate locations) are being calculated. Courtesy of S. Lebedev Mid-Term Review Meeting, February 13 -14, Tutzing www. spice-rtn. org
Database of existing models (ETH) Most published models can easily be retrieved, plotted and compared. All model coefficients are distributed in a fixed format (Becker and Boschi, 2001) and where possible in the original format. All necessary reading software is also available. Becker and Boschi, 2001 Mid-Term Review Meeting, February 13 -14, Tutzing www. spice-rtn. org
Assessment of existing models In progress: So far, we contributed to the software database with the following codes: • Calculation of seismograms using normal modes (IPGP) • Modelling of propagation of surface waves in 3 D structures by the mode coupling method (Ui. O) • Calculation of phase velocity dispersion curves (IPGP) • Ray tracing for body and surface waves in anisotropic media (ETH, UOx) • Spherical harmonic package (ETH-USC) Mid-Term Review Meeting, February 13 -14, Tutzing www. spice-rtn. org
Tomographic techniques • Exact ray theory predicts multipathing to be more important than previously thought. (Ferreira and Woodhouse, 2005) • Crustal corrections using SEM (UU), local modes (Ui. O), exact ray theory (UOx) • Imaging using the neighbourhood algorithm and neural networks (UU) • Covariance and resolution matrices for finely parameterized models (ETH) Mid-Term Review Meeting, February 13 -14, Tutzing www. spice-rtn. org
European reference model In search of a consensus of what a European reference model should be, we (INGV and UU) organized a special session at EGU 05 and EGU 06 focused on different aspects of reference models. Mid-Term Review Meeting, February 13 -14, Tutzing www. spice-rtn. org
Ph. Ds and postdocs • IPG Paris: 1) Yilong Qin, A SPICE synthetic dataset to benchmark global tomographic methods (Ui. O) • INGV Bologna: 2) Daniel Stich, Spectral element moment tensor inversion from regional seismograms 3) Reneta Raykova, Local surface wave tomography from a broadband dense array in Northern Apennines 4) Eoin Mc. Manus, • University of Oxford: Comparisons of ray theory with measurements made on spectral-element synthetic seismograms (UU) 5) Ebru Bozdag propagation (UOx) • University of Utrecht: Testing and improving tomographic models using 3 D numerical wave 6) Anne Sieminski, 3 D anisotropy sensitivity kernels using adjoint methods • ETH Zurich 7) Daniel Peter, Global surface wave tomography: membrane waves and adjoint methods (UOx) • University of Oslo: 8) Digdem Acarel, Surface Wave Synthetic Data in Heterogeneous Regions (UU) 9) Laurent Guillot, Coupled local and radiation modes in regional seismic wave propagation Mid-Term Review Meeting, February 13 -14, Tutzing www. spice-rtn. org
- Slides: 10