## 6 Discussion  
This study shows a comparison between the conventional and land-streamer setup for recording field seismic data. The comparison listed here can be divided into two main parts: (1) data comparison and (2) result comparison. The data comparison shows that both conventional and land-streamer traces have the same signal-to-noise ratio (SNR), same data quality in the time, frequency, and wavenumber domains. However, the conventional setup is characterized by higher SNR at larger offsets. From our experience, the SNR of land-streamer data depends on several factors, such as the weight of the receiver plates, the terrain of the ground surface, and the source used in the data recording. In general, source-receiver offset in land-streamer surveys should not exceed 300 m (150 m is a common land-streamer length) unless in special cases such as sites with very low attenuation or when using a strong seismic source. For shallow applications, the land-streamer setup has more advantages than conventional setup; it saves time during installing and collecting equipment as well as covers larger areas in much shorter time relative to conventional setup; note that the data quality is almost the same; hence, the land-streamer setup would be preferred in such cases. The main shortage in a land-streamer survey is that the maximum penetration depth is smaller than the conventional survey. In terms of result comparison, despite that the conventional setup has more data and deeper penetration, we noticed that the land-streamer survey yields better results in shallow depth relative to the conventional setup (see Figures 8 and 9) even if we used the same source and receiver offsets. For example, Table 3 shows a comparison between the tomogram generated from the conventional setup (Figure 8a) and that generated from a land-streamer setup (Figure 9b). The numbers shown in Table 3 are in favor of the conventional setup; (1) more picks, (2) larger source-receiver offset, and (3) larger penetration depth, however, the tomogram of the land-streamer (Figure 9b) shows a better mapping of the near-surface anomalies relative to the conventional tomogram (Figure 8a), which is also true in case of source and receiver offsets 2.0 m and 5.0 m. Tables 4 and 5 show a numerical comparison between the conventional tomogram vs. true model (Table 4) and the land-streamer tomogram vs. the true model (Table 5). Both comparisons are conducted with respect to the result of the 1m geophone interval, i.e., the conventional tomogram shown in Figure 8a, and the land-streamer tomogram shown in Figure 9b. Results in Table 4 shows that:  
* Anomaly A is not shown at the conventional-seismic tomogram
* The center position of the local anomalies B, C, and D has no errors
* The errors in imaging the anomalies' width are ranging between 77% and 145%
* The errors in imaging the anomalies' thickness are ranging between 35% and 50% \begin{table}
\begin{tabular}{c c c} \hline \hline  & **Conventional** & **Land-Streamer** \\ \hline Source interval (m) & 1 & 1 \\ Receiver interval (m) & 1 & 1 \\ No. of picks & 202,500 & 35,000 \\ Maximum source-receiver offset (m) & 450 & 100 \\ Depth of penetration (m) & 80 & 28 \\ Number of iterations & 23 & 23 \\ Minimum RMS error (ms) & 8 & 2.3 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Comparison between conventional and land-streamer results. * While Table 5 shows that:
* All four local anomalies are shown at the land-streamer-seismic tomogram
* The center position of all local anomalies has no errors
* The errors in imaging the anomalies' width are ranging between 5% and 12%
* The errors in imaging the anomalies' thickness are ranging between 10% and 20%  
This numerical comparison clearly shows that the land-streamer can detect the near-surface local anomalies with higher accuracy relative to the conventional seismic data.