A long lost ship, named Terra Nova, was found in the seabed of Greenland. It was discovered by a group of people testing echo-sounding equipment around the area. When they saw an unidentified feature within their data they decided to use sonar-mapping to determine what this feature was. They matched the length of the feature to the length of the Terra Nova and sent some cameras down to photograph the feature. They found it to be a wooden ship which matched the description of the Terra Nova.
The article describing the Terra Nova and it’s discovery can be found here.
This is an example of how sonar-mapping may reveal interesting features that may be relevant to an archaeologist. This technology can be used for surveying areas in order to determine where to begin excavations or simply to get a bigger picture of the current site. In fact, sonar mapping is already used by some archaeologists for this exact purpose (for an example check out this article).