  We introduce a new model of gamma ray burst (GRB) that explains its observed
prompt signals, namely, its primary quasi-thermal spectrum and high energy
tail. This mechanism can be applied to either assumption of GRB progenitor:
coalescence of compact objects or hypernova explosion. The key ingredients of
our model are: (1) The initial stage of a GRB is in the form of a relativistic
quark-gluon plasma "lava"; (2) The expansion and cooling of this lava results
in a QCD phase transition that induces a sudden gravitational stoppage of the
condensed non-relativistic baryons and form a hadrosphere; (3) Acoustic shocks
and Alfven waves (magnetoquakes) that erupt in episodes from the epicenter
efficiently transport the thermal energy to the hadrospheric surface and induce
a rapid detachment of leptons and photons from the hadrons; (4) The detached
$e^+e^-$ and $\gamma$ form an opaque, relativistically hot leptosphere, which
expands and cools to $T \sim mc^2$, or 0.5 MeV, where $e^+e^- \to 2\gamma$ and
its reverse process becomes unbalanced, and the GRB photons are finally
released; (5) The "mode-conversion" of Alfven waves into electromagnetic waves
in the leptosphere provides a "snowplow" acceleration and deceleration that
gives rise to both the high energy spectrum of GRB and the erosion of its
thermal spectrum down to a quasi-thermal distribution. According to this model,
the observed GRB photons should have a redshifted peak frequency at $E_p \sim
\Gamma(1 + \beta/2)mc^2/(1 + z),$ where $\Gamma\sim {\cal{O}}(1)$ is the
Lorentz factor of the bulk flow of the lava, which may be determined from the
existing GRB data.
