  In this letter we present the results of a wavelet analysis of the radio
light curve of the BL Lac Object PKS B0048-097 from the University of Michigan
Radio Astronomy Observatory monitoring program at 8GHz during twenty-five
years, from 1979 to 2004. The results show a remarkable periodicity of 450-470
days in the early 1980s that changed to a ~585 day periodicity in the late
1980s to early 1990s. A less pronounced ~400 day periodicity is found after
\~1995. Very-long-baseline interferometry imaging at 15GHz shows dramatic
structural changes in the usually unresolved source between two epochs, 1995.57
and 2002.38. The pronounced northward directed jet seen in the 2002 image
differs by more than 90 degrees in direction from the source structure found in
earlier epochs. These findings make PKS B0048-097 a primary target for
multi-wavelength observations and intensive radio monitoring to decipher the
blazar-variability phenomenon.
