  Many radio pulsars exhibit glitches wherein the star's spin rate increases
fractionally by $\sim 10^{-10} - 10^{-6}$. Glitches are ascribed to variable
coupling between the neutron star crust and its superfluid interior. With the
aim of distinguishing among different theoretical explanations for the glitch
phenomenon, we study the response of a neutron star to two types of
perturbations to the vortex array that exists in the superfluid interior: 1)
thermal motion of vortices pinned to inner crust nuclei, initiated by sudden
heating of the crust, (e.g., a starquake), and 2) mechanical motion of
vortices, (e.g., from crust cracking by superfluid stresses). Both mechanisms
produce acceptable fits to glitch observations in four pulsars, with the
exception of the 1989 glitch in the Crab pulsar, which is best fit by the
thermal excitation model. The two models make different predictions for the
generation of internal heat and subsequent enhancement of surface emission. The
mechanical glitch model predicts a negligible temperature increase. For a pure
and highly-conductive crust, the thermal glitch model predicts a surface
temperature increase of as much as $\sim$ 2%, occurring several weeks after the
glitch. If the thermal conductivity of the crust is lowered by a high
concentration of impurities, however, the surface temperature increases by
$\sim$ 10% about a decade after a thermal glitch. A thermal glitch in an impure
crust is consistent with the surface emission limits following the January 2000
glitch in the Vela pulsar. Future surface emission measurements coordinated
with radio observations will constrain glitch mechanisms and the conductivity
of the crust.
