  The issue whether Moreton waves are flare-ignited or CME-driven, or a
combination of both, is still a matter of debate. We develop an analytical
model describing the evolution of a large-amplitude coronal wave emitted by the
expansion of a circular source surface in order to mimic the evolution of a
Moreton wave. The model results are confronted with observations of a strong
Moreton wave observed in association with the X3.8/3B flare/CME event from
January 17, 2005. Using different input parameters for the expansion of the
source region, either derived from the real CME observations (assuming that the
upward moving CME drives the wave), or synthetically generated scenarios
(expanding flare region, lateral expansion of the CME flanks), we calculate the
kinematics of the associated Moreton wave signature. Those model input
parameters are determined which fit the observed Moreton wave kinematics best.
Using the measured kinematics of the upward moving CME as the model input, we
are not able to reproduce the observed Moreton wave kinematics. The
observations of the Moreton wave can be reproduced only by applying a strong
and impulsive acceleration for the source region expansion acting in a piston
mechanism scenario. Based on these results we propose that the expansion of the
flaring region or the lateral expansion of the CME flanks is more likely the
driver of the Moreton wave than the upward moving CME front.
