  We calculate the $T$-matrices of elastic pion-nucleon ($\pi N$) scattering up
to fourth order in SU(3) heavy baryon chiral perturbation theory. The pertinent
low-energy constants are determined by fitting to $\pi N$ phase shifts below
200 MeV pion laboratory momentum in the physical region. The scattering lengths
and scattering volumes are extracted from the chiral amplitudes, and turn out
to be in good agreement with those of other approaches and the available
experimental values. We also discuss the subthreshold parameters and the
related issues. On the basis of the various phase shifts, the threshold
parameters and the subthreshold parameters, the convergence of the chiral
expansion is analyzed in detail. The calculation provides the possibility to
consider explicitly more complex processes involving strangeness.
