TG Planetary scale

TG Meeting Planetary Scale, Bologna, December 2005. The focus of this TG meetings was on any aspects of wave propagation and imaging on a scale where the (near-) spherical geometry of our planet has to be accounted for. This area undergoes a fundamental change at the moment, primarily in connection with the computational methods that are being further developed and applied within SPICE: we are now able to carry out 3D simulations for globally observed large earthquakes almost on a routine basis. At this meeting it was decided to undertake a benchmarking exercise of global inversion algorithms using complete 3D synthetic seismograms derived from spectral element calculations. The goal is to test how current imaging techniques are limited by approximations in theory and the inadequacy of data quality and coverage. Our set of synthetic seismograms is now already available to the community worldwide. One development within SPICE is the initiation of a European effort to improve our knowledge of crust and mantle structure in the European and Mediterranean region. SPICE focuses on devising methods and tools that will be applied to identify a new consensus model in the framework of FP6 project NERIES. Determining a new model requires that we assess the quality of existing ones: we collect a database of global and regional tomographic models (available on the SPICE www pages), and provide tools for their visualization and comparison.