  We compare in detail the results of simulations of electromagnetic showers in
ice in the GeV-TeV energy range, using both the GEANT package and the ZHS Monte
Carlo, a code specifically designed to calculate coherent Cerenkov radio pulses
from electromagnetic showers in dense media. The longitudinal and lateral
profiles as well as the tracklengths, and excess tracklengths are shown to
agree at the 10% level. We briefly comment on the negligible influence of the
Landau-Pomeranchuk-Migdal effect on the total shower tracklength. Our results
are relevant for experiments exploiting the radio Cerenkov technique in dense
media as well as for other detectors that rely on the Cerenkov effect in water
or ice.
