Archaeology: Sonar Imaging

Sonar imaging is the use of acoustics to produce images in order to locate objects found underwater. Used in the field of underwater archaeology, sonar imaging is quickly becoming an increasingly important tool in the location of valuable archaeological findings that would otherwise be lost. Underwater archaeology is an interdisciplinary form of archaeology, which combines such scientific fields as anthropology, chemistry, oceanography and ethnography, along with the protocols of archaeology.

Sonar imaging works by sending and receiving signals using a single unit known as a transducer. The transducer emits a sound pulse through the water, which then hits the target and returns to the traducer. This sequence produces an image by measuring the time it takes for the wave to return, as well as the strength of the wave.

Sonar imaging provides different types of images; bathymetric sonar provides researchers with vertical depth information. Side-scan sonar provides a comprehensive image on the bottom of the body of water. This latter type of sonar is extremely sophisticated and enables an easy and swift analysis of the lower depths of water bodies, and also provides sideways views. Because it can provide high-quality images at several angles, side-scan sonar enables researchers to analyze objects located just above the seafloor.

Sonar imaging is of benefit to underwater archaeologists because it reduces the cost of diver run searches, while providing a higher rate of success in finding archaeological objects of value hidden underwater. Sonar imaging is such an important tool because it uses acoustics in order to locate objects. Sound is the most effective method in which to make observations underwater because, compared to light, which is easily scattered underwater, sound travels quickly through water, making it a valuable archaeological tool.

In addition to sonar imaging, most underwater archaeological analyses are performed using standard scuba equipment, simple measuring, mapping, drawing and other such techniques traditionally used in field archaeology.

Sonar imaging is so important to underwater archaeology because it can be used to find a variety of archaeologically significant objects. Such objects include artifacts, historically important sites such as religious sites and burial sites, as well as cities and villages that have been submerged due to changing sea levels.

Furthermore, sonar imaging may also be coupled with such technologically-sophisticated tools as infrared, robotic and optical equipment, which is used by underwater archaeologists in order to locate, map and document important archaeological sites in order to conduct further research and more in-depth scientific analysis.