  We consider the Cauchy problems in the whole space for the wave equation with
a weighted L^{1}-initial data. We first derive sharp infinite time blowup
estimates of the L^{2}-norm of solutions in the one and two dimensional cases.
Then, we apply it to the local energy decay estimates for n = 2, which is not
studied so completely when the 0-th moment of the initial velocity does not
vanish. The idea to derive them is strongly inspired from a technique used in
the author's previous papers.
