“…In contrast, the the free-surface multiples contain down-going energy. Since we have both the hydrophone and vertical geophone recording, we use dualsensor summation (Jiao, et.al., 1998;Barr, et.al., 1996;Barr, 1997;Barr and Sanders, 1989;Barr, et.al., 1997;Dragoset and Barr, 1994;Paffenholz and Barr, 1995;Ball and Corrigan, 1996;Soubaras, 1996;Canales and Bell, 1996;Loewenthal, 1994;Loewenthal and Robinson, 2000;Robinson, et.al., 1999) to separate the up-going Figure 11. Cartoon showing the arrivals that causes the two reflection events D and E shown in Figure 7.…”