Mini-streamer

The Mini-Streamer will most often be used as a supplement during Ocean Bottom Surveys. In this type of survey, the recording instruments are first put on a gridded line on the ocean bottom. Then the ship turns and fires the seismic energy source over the same line. Operating with offsets (distance between source and first recorder) of tens of kilometers, sometimes several hundred kilometers, the source must be able to output low-frequency, high amplitude signals. In practice, several high-volume airguns are used.

http://www.geo.uib.no/eworkshop/index.php?n=Main.Streamers