  Gamma-ray bursts (GRBs) are some of the most extreme events in the Universe.
As well as providing a natural laboratory for investigating fundamental
physical processes, they might trace the cosmic star formation rate up to
extreme redshifts and probe the composition of the intergalactic medium over
most of the Universe's history. Radio observations of GRBs play a key part in
determining their physical properties, but currently they are largely limited
to follow-up observations of $\gamma$-ray-detected objects. The SKA will
significantly increase our ability to study GRB afterglows, following up
several hundred objects in the high frequency bands already in the "early
science" implementation of the telescope. SKA1-MID Bands 4 (4 GHz) and 5 (9.2
GHz) will be particularly suited to the detection of these transient phenomena.
The SKA will trace the peak of the emission, sampling the thick-to-thin
transition of the evolving spectrum, and follow-up the afterglow down to the
time the ejecta slow down to non-relativistic speeds. The full SKA will be able
to observe the afterglows across the non-relativistic transition, for ~25% of
the whole GRB population. This will allow us to get a significant insight into
the true energy budget of GRBs, probe their surrounding density profile, and
the shock microphysics. The SKA will also be able to routinely detect the
elusive "orphan afterglow" emission, from the population of GRBs whose jets are
not pointed towards the Earth. We expect that a deep all-sky survey such as
SKA1-SUR will see around 300 orphan afterglows every week. We predict these
detection to be >1000 when the full SKA telescope will be operational.
