Seismic profiles of the shelf east (upper) and west (lower) of the Sepik River. The eastern shelf (profile PNG-97-08) is characterized by a prominent shelf-edge (relict?) reef that is nearly buried by recent(?) terrigenous sediment, some of which has by-passed the reef and accumulated on the slope. The western shelf (profile PNG-97-02) has a sediment wedge (up to 60 ms/45 m thick) prograding over the shelf edge; in contrast to the east, there is no evidence of an underlying reef. See Sepik base map for profile locations.