Multiscale seismic imaging of the eastern Nankai trough by full waveform inversion

[1] Classical active seismic methods fail to sharply image the earth’s deep crust. We present the first crustal-scale application of 2-D full waveform inversion based on dense ocean bottom seismic data to investigate the Eastern Nankai subduction system (Japan). This approach allows to quantify seismic velocities up to an unprecedented degree of resolution. Results reveal compressive tectonic features within both the subducting oceanic crust and the backstop. At depth, velocity anomalies along major faults and structural discontinuities bring evidence for the presence of fluids and weakened material and also for a possible coseismic slip partitioning structure. INDEX TERMS: 0902 Exploration Geophysics: Computational methods, seismic; 3025 Marine Geology and Geophysics: Marine seismics (0935); 8010 Structural Geology: Fractures and faults; 8105 Tectonophysics: Continental margins and sedimentary basins (1212). Citation: Dessa, J.-X., S. Operto, S. Kodaira, A. Nakanishi, G. Pascal, J. Virieux, and Y. Kaneda (2004), Multiscale seismic imaging of the eastern Nankai trough by full waveform inversion, Geophys. Res. Lett., 31, L18606, doi:10.1029/2004GL020453.