code: def _get_site_scaling_term(self, C, vs30):
          
          site_amp = C["xi"] * np.log(1200.0) * np.ones(len(vs30))
          idx = vs30 < 1200.0
          site_amp[idx] = C["xi"] * np.log(vs30[idx])
          return site_amp
docs: Returns the site scaling. For sites with Vs30 > 1200 m/s the site
          amplification for Vs30 = 1200 is used