The transient motion of a ramp-core dislocation spreading from -infinity <x
< infinity and jumping from rest to a supersonic speed in the x direction,
is investigated by analysis on the complex transform plane. The new result
of this analysis is thar, instead of the Mach cone of the Volterra disloca
tion, there are two lines of discontinuity (of the stress) propagating in t
he +/-z directions, inside of which there are arctan delta sequence (epsilo
n not equal0) radiated supersonic fields, as well as subsonic fields. The l
ines of discontinuity arise at the tangent point of the Mach wavefront (eps
ilon =0) to the cylinder with radius r=c(2)t.