Abstract: Method and apparatus for converting tube waves into body waves downhole for seismic exploration are disclosed, comprising a rotary valve tube wave source for producing swept frequency tube waves that are injected into a tubing or wellbore. The tube waves are converted to body waves by an elongate tube wave converter located at a selected position downhole. The tube wave converter comprises an elongate body that preferably substantially fills the wellbore or tubing and has a preferred shape in order to convert efficiently the tube waves to body waves at the selected position downhole.