  We study the second order Coleman - de Luccia instanton which appears as the
curvature of the effective potential reaches a sufficiently large value. We
show how one can find the approximative formula for this instanton by
perturbative expansion in the case when the second derivative of the effective
potential divided by the Hubble parameter squared is close to -10, and we
perform a numerical study of this instanton in the case of quasi-exponential
potential.
