If the chart states that the sounds are from the 1940 to 1969, which surveying method was used?

If the chart states that the sounds are from the 1940 to 1969, which surveying method was used?

• A. Multi-beam sonar
• B. Single beam sonar
• C. Side-scan sonar
• D. Satellite imagery

Answer: (B)

The surveying method indicated in the question is single beam sonar. This method was commonly used during the periods mentioned (1940 to 1969) for bathymetric surveys, which involve measuring the depth of water and mapping underwater features. Single beam sonar works by sending out a single sonar pulse from a transducer and measuring the time it takes for the echo to return after bouncing off the seabed. This method provided a straightforward way to gather depth information but was limited in that it only collects data along a single line of travel, requiring multiple passes to build a comprehensive bathymetric map. In contrast, multi-beam sonar, which became more widely used in later years, captures data across a swath of the seabed simultaneously, providing a more detailed and accurate representation of underwater features. Side-scan sonar, primarily used for object detection and mapping the seafloor's texture, also gained prominence after the 1960s. Satellite imagery assists in cataloging large areas from above but does not provide direct data about seafloor depth, particularly not during the stated timeline. Therefore, single beam sonar is the appropriate choice for the surveying methods used during that era.

The surveying method indicated in the question is single beam sonar. This method was commonly used during the periods mentioned (1940 to 1969) for bathymetric surveys, which involve measuring the depth of water and mapping underwater features. Single beam sonar works by sending out a single sonar pulse from a transducer and measuring the time it takes for the echo to return after bouncing off the seabed. This method provided a straightforward way to gather depth information but was limited in that it only collects data along a single line of travel, requiring multiple passes to build a comprehensive bathymetric map.

In contrast, multi-beam sonar, which became more widely used in later years, captures data across a swath of the seabed simultaneously, providing a more detailed and accurate representation of underwater features. Side-scan sonar, primarily used for object detection and mapping the seafloor's texture, also gained prominence after the 1960s. Satellite imagery assists in cataloging large areas from above but does not provide direct data about seafloor depth, particularly not during the stated timeline. Therefore, single beam sonar is the appropriate choice for the surveying methods used during that era.