Figure 13. West of Site 900, basement topography is characterized by alternating, small-scale highs and basins between Sites 900 and 898, where the basement high is cut by a series of oceanward-dipping normal faults. Thick, lens-shaped sequences extend over a range of 40 km on top of the basement. Reflection F, cutting towards the west below the basement high of the proposed drill location IAP-7, may be a low-angle normal fault. F may either represent on the west flank of Site 900 the same structure as H east of it, or it may be a separate feature, different from H. Therefore, the crustal block at IAP-7 may either be an upper-plate or a lower-plate fault block to the master detachment H.