  We study the fully nonlinear dynamical evolution of binary black hole data,
whose orbital parameters are specified via the effective potential method for
determining quasi-circular orbits. The cases studied range from the
Cook-Baumgarte innermost stable circular orbit (ISCO) to significantly beyond
that separation. In all cases we find the black holes to coalesce (as
determined by the appearance of a common apparent horizon) in less than half an
orbital period. The results of the numerical simulations indicate that the
initial holes are not actually in quasi-circular orbits, but that they are in
fact nearly plunging together. The dynamics of the final horizon are studied to
determine physical parameters of the final black hole, such as its spin, mass,
and oscillation frequency, revealing information about the inspiral process. We
show that considerable resolution is required to extract accurate physical
information from the final black hole formed in the merger process, and that
the quasi-normal modes of the final hole are strongly excited in the merger
process. For the ISCO case, by comparing physical measurements of the final
black hole formed to the initial data, we estimate that less than 3% of the
total energy is radiated in the merger process.
