## 4 Results  
### Morphology of Channels Complexes Erosional Surface and Seismic Facies of Its Filling Deposits  
The main morphology of the channel's complexes erosional surface identified in the study area includes flank, wall, terrace, and thalweg (Figure 5). At the same time, seismic facies analysis is based on the reflection configuration of channel fills, and the shape of this erosional surfaces revealed four different types of channel complexes in the study area (Figure 6):  
* Type 1 (Vertical migrating channels)
* Type 2 (lateral migrating channels)
* Type 3 (V-shaped channels)
* Type 4 (U-shaped channels). In Type 1, the flank, wall, and thalweg features of channels complexes, the erosional surface is present in the western to eastern areas with proto flank existed in the eastern area of the channel complexes 1 (Figure 5a). The flank is characterized by low to high seismic amplitude with relatively continuous reflectors, while the erosional surface of channels complexes wall has discontinuous reflectors due to faulted and differential compaction (Figures 5a and 6a). In addition, the dip angle of the flank varied from horizontal to dipping flank with sediment wave in the flank. In contrast, the dip angle of the channel wall is relatively steep (>40\({}^{\circ}\)) in the western and eastern areas and less steep (<40\({}^{\circ}\)) in the middle area. Furthermore, the seismic facies of Type 1 are characterized by low to high amplitude, high continuity, and sub-parallel seismic reflections confined with a relatively V to U-shaped erosional surface. In addition, seismic facies inside the channel complexes show lateral and uniform fill reflection, which is mostly on-lapping into the erosional surface, and the exaggeration of the channel is in a relatively vertical direction (Figures 5a and 6a). The morphology of Type 2 channels complexes consists of flank, wall, and thalweg that span from western to eastern areas (Figure 5b). The channels flank is characterized by medium to high seismic amplitude with relatively continuous reflectors, while the erosional surface of channels complexes wall has discontinuous low to high reflectors due to faulted and differential compaction (Figures 5b and 6b). The dip angle of the flank is mostly horizontal, with some dipping flank, especially in the western area (Figure 6b). In contrast, the dip angle of the channel wall is relatively steep (>40\({}^{\circ}\)) throughout the western to eastern areas. In Type 2 channel complexes, the seismic facies of the filling deposits consist of parallel to subparallel seismic reflections, variable low to high seismic amplitude, and continuity with a wider-shape erosional surface that is highly deformed (Figures 5b and 6b). Furthermore, the channels fills are present along the wall of the previous channels, which depicts that the channels are laterally migrating and on-lapping to the previous channel's erosional surface (Figure 6b). In addition, bright seismic amplitudes are present at the base of Type 2 on the western to eastern areas (Figures 5b and 6b). Type 3 V-shaped channel complexes consist of flank, terrace (only found at this channel type), wall, and thalweg morphology presented in the western to eastern of study areas (Figure 5c). The channel flank is characterized by low to medium seismic amplitude with relatively continuous and dipping reflectors, while the terrace and wall have discontinuous low to medium reflectors due to faulting and differential compaction (Figures 5c and 6c). The dip angle of the terrace is relatively flat, whereas the wall of the channel is mostly steep, with more than 40\({}^{\circ}\) throughout the western to the eastern area (Figure 5c). The seismic facies of this Type 3 filling deposits consist of subparallel to parallel seismic reflectors, moderate amplitude, and variable continuity with V-shaped erosional surface. In addition, the reflections are on-lapping to the channel erosional surface.