  In this work, we investigate the gravitational quasinormal modes (QNMs) and
the gravitational resonances of a thick brane model. We use the asymptotic
iteration and shooting methods to obtain the quasinormal frequencies (QNFs) of
the brane. On the other hand, we investigate the resonances and their evolution
numerically. The results show that the oscillations of the resonances equal (up
to numerical error) to the real parts of the QNFs, while the damping rates of
the resonances equal to the imaginary parts of the QNFs. The QNMs and
resonances, both of them can be regarded as the characteristic modes of the
thick brane, are closely related with each other. In addition, the lifetime of
these QNMs could be very long, perhaps they might be detected in future
accelerator or gravitational wave detector.
