  Using the High Dispersion Spectrograph at the Subaru Telescope, echelle
spectra of two giant arcs, i.e. nebulosities Cw and L associated with HH 131 in
Orion are presented. Typical emission lines of Herbig-Haro objects have been
detected towards Cw. With the 2.16 m telescope of National Astronomical
Observatories, spectra of Nebu. C, L and K are obtained, which also show strong
[SII]6717/6731, H$\alpha$ and [NII]6583 emission lines. Position-velocity
distributions of Cw and L are analyzed. The fastest radial velocity of Cw is
V_r ~ -18.0 km/s. When the flow at L goes to the south, it slows down. The
fastest radial velocity of L has been observed of -45.0 km/s and the slowest
value is about -18.3 km/s. The similarity of the velocities and their
positional connection indicate that Cw and L are physically associated. The
entire flow tends to become less excited and less ionized when going further to
the south (i.e., from Nebu. K, L to C). The electron densities of all the
observed nebulosities are low (n_e ~ 10^2 cm^-3). Double kinematic signatures
have been found in Cw from its [NII]6583 profiles while the observed H$\alpha$
profiles of Cw are almost symmetric. Bow shock models appear to agree with the
observed position-velocity diagrams of the [NII spectra better than H$\alpha$
spectra. With the suggestion that these arcs are HH shocks possibly ejected out
of the Orion A molecular cloud by an uncertain source, their spectra show low
to intermediate excitation from their diagnostic line ratios.
