One suggested explanation for the origin of deviatoric, non-double-couple earthquake sources is that there is slip along curved fault surfaces. Here we compute the moment tensor components for earthquakes along idealized faults which are surfaces of revolution. The calculations show that when the slip direction is around the axis of revolution, the earthquakes may possess purely double-couple sources, or purely compensated linear vector dipole (CLVD) sources, depending on the geometry of the fault and the slip. However, a surprising result is that the CLVD components is always zero for unidirectional slip along surfaces having a suitable degree of symmetry. Thus slip along a large variety of simple and plausible curved fault geometries produces a purely double-couple source. ¿ American Geophysical Union 1990