Fig. 7

Comparisons of the 3D seismic images, structural features, and VLFE source distributions. a CMT solutions within 4 km, approximately the maximum spatial error, from line IL2500 are projected on the seismic section. The vertical exaggeration (VE) of the seismic section is 1.5. Most of the selected VLFEs are located in low-reflectivity underthrust sediments on the landward side of the central ridge in the oceanic crust and are thought to consist of underconsolidated hemipelagic muds. b The oceanic crust topography and VLFE distribution with the CMT solutions. A cluster of VLFEs is located on the landward side of the central ridge in the oceanic crust. c The décollement topography and fault distribution in the shallow imbricated thrust sequence. The conjugate faults are also located on the landward side of the topographic high of the décollement. These comparisons imply that the maximum stress direction, which is inferred from the conjugate faults in the imbricated thrust zone, is consistent with the slip direction of VLFEs and the spatial relation between the VLFE distribution and the oceanic crust ridge. The consistencies suggest that the activity and distribution of VLFEs are controlled by the relief of the oceanic crust affecting the present stress field in the overlying sequence