We are proposing a 2-ship experiment to acquire 3D controlled source seismic imaging data on the continental margin of Chile. If both the NSF and German proposals are funded, OBSs will be deployed by the R/V SONNE and the R/V Marcus Langseth will provide sources as well as MCS data acquired using their long hydrophone streamer. If only the NSF project is funded, then a somewhat scaled down survey will be conducted with OBSs deployed and recovered from Langseth.