  This paper aims to evince the corrections on the black string warped horizon
in the braneworld paradigm, and their drastic physical consequences, as well as
to provide subsequent applications in astrophysics. Our analysis concerning
black holes on the brane departs from the Schwarzschild case, where the black
string is unstable to large-scale perturbation. The cognizable measurability of
the black string horizon corrections due to braneworld effects is investigated,
as well as their applications in the variation of quasars luminosity. We delve
into the case wherein two solutions of Einstein's equations proposed by
Casadio, Fabbri, and Mazzacurati, regarding black hole metrics presenting a
post-Newtonian parameter measured on the brane. In this scenario, it is
possible to analyze purely the braneworld corrected variation in quasars
luminosity, by an appropriate choice of the post-Newtonian parameter that
precludes Hawking radiation on the brane: the variation in quasars luminosity
is uniquely provided by pure braneworld effects, as the Hawking radiation on
the brane is suppressed.
