  Microscopic RPA calculations based on the cranked shell model are performed
to investigate the quadrupole and octupole correlations for excited
superdeformed (SD) bands in even-even A=190 nuclei. The K=2 octupole vibrations
are predicted to be the lowest excitation modes at zero rotational frequency.
The Coriolis coupling at finite frequency produces different effects depending
on the neutron and proton number of nucleus. The calculations also indicate
that some collective excitations may produce J(2) moments of inertia almost
identical to those of the yrast SD band. An interpretation of the observed
excited bands invoking the octupole vibrations is proposed, which suggests
those octupole vibrations may be prevalent in even-even SD A=190 nuclei.
