  We consider the Cauchy problems in n-dimensional Euclidean space for the
plate equation with a weighted L^{1}-initial data. We derive optimal estimates
of the L^{2}-norm of solutions for n = 1, 2, 3, 4. In particular, such obtained
results express infinite time blowup properties in the case when the 0-th
moment of the initial velocity does not vanish. The idea to derive them is
strongly inspired from an already developed technique by the author's
collaborative works.
