Figure 6. Filtered record section of a portion of the near-bottom Fluigal single-channel profile 10 located in Figure 2. Shots every 12 s with a speed of the SAR about 1.5 knots. Vertical scale in seconds. The first arrival is the direct arrival. About 0.1 s below is the sea-bottom reflection. Linear oblique stripes correspond to SAR mud penetrator interferences. To avoid interactions within the first second of the useful recording sequence, they were manually offset on the ship by shifting the shooting sequence. Though the sea bottom is flat, the traveltime of the direct arrival, which varies from 4.1 to 4.6 s, is a function of the cable length of the SAR. The cable length is adjusted in order to maintain the SAR at about 80 m above the seafloor but depends on such factors as weather, currents, or the speed of the ship. The arrival at about 5.75 s is the third conventional multiple of the preceding shot.

Figure 6. Filtered record section of a portion of the near-bottom Fluigal single-channel profile 10 located in Figure 2. Shots every 12 s with a speed of the SAR about 1.5 knots. Vertical scale in seconds. The first arrival is the direct arrival. About 0.1 s below is the sea-bottom reflection. Linear oblique stripes correspond to SAR mud penetrator interferences. To avoid interactions within the first second of the useful recording sequence, they were manually offset on the ship by shifting the shooting sequence. Though the sea bottom is flat, the traveltime of the direct arrival, which varies from 4.1 to 4.6 s, is a function of the cable length of the SAR. The cable length is adjusted in order to maintain the SAR at about 80 m above the seafloor but depends on such factors as weather, currents, or the speed of the ship. The arrival at about 5.75 s is the third conventional multiple of the preceding shot.