. Collected reprints / Atlantic Oceanographic and Meteorological Laboratories [and] Pacific Oceanographic Laboratories. Oceanography Fig. 2. Time-distance plot of profile A. the time-distance graph. tible to noise. Synthetic seismograms. Synthetic seismo- grams were produced for various crustal models inferred from the seismic and gravity data by an iterative program based on ray theory [Dash et al., 1970]. This approach assumes that the geological units constituting the model are isotropic, elastic, and homogeneous media with no attenuation of seismic energy and are two-dimensio
. Collected reprints / Atlantic Oceanographic and Meteorological Laboratories [and] Pacific Oceanographic Laboratories. Oceanography Fig. 2. Time-distance plot of profile A. the time-distance graph. tible to noise. Synthetic seismograms. Synthetic seismo- grams were produced for various crustal models inferred from the seismic and gravity data by an iterative program based on ray theory [Dash et al., 1970]. This approach assumes that the geological units constituting the model are isotropic, elastic, and homogeneous media with no attenuation of seismic energy and are two-dimensional with interfaces between the rock units normal to the plane of section. Results All the seismograms obtained were subjected to the processing techniques described above, and the results obtained for each profile are indicated below. Line A. This line was shot between Sao Tiago on the south and Sao Vicente on the north with Sal as the broad side listening point (Figure 1). The lateral separation between Sao Tiago and Sao Vicente is about 200 km, and as can be seen from the time-distance plot (Figure 2), the two stations provide a reversed profile. The mean water depth along this line was about 3000 m. The observed times were corrected for shot and detector locations. The thickness and velocity of the various layers are shown in Table 1. Line B. This line was shot between the islands of Sao Tiago and Sal. The station at Sao Vicente acted as the broadside listening point. The time-distance plot is shown in Figure 3. As Figure 3 shows, this line presented an interesting problem. The station at Sao Tiago registered the seismic arrivals from above the Moho up to a distance of about 100 km. However, the station at Sal failed to register any arrivals at all for shots fired beyond 30 km. Within 30 km the arrivals were strong and readily recognizable. The most plausible explanation for this loss of energy is that the shots were being fired beyond a heavily faulted or fractured zone wh
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