3:00 PM - 4:00 PM
[J08-P-02] Waveform inversion to image laterally inhomogeneous crustal structure - comparison among waveform inversion, traveltime inversion, and seismic migration -
In the fore-arc region of the Izu-Bonin island arc, Tatsumi and Stern (2006) suggested a sub-vertical intrusion of the middle crust below the Eocene paleo arc. For assessing the existence of such intrusive structural feature, we conducted MCS survey and wide-angle OBS-airgun survey (OBS deployed 1 km interval) in this region (Yamashita et al., 2009). We applied pre-stack depth migration to the MCS data, but we could not image the intrusive feature. On the contrary, we attempted to apply FWI to this wide-angle OBSs dataset and we succeeded in imaging this intrusive feature. From these results, we may deduce that the FWI is an effective tool for detecting steep tectonic structures such as sub-vertical intrusion.