code: def _compute_mean(self, C, g, mag, hypo_depth, rrup, vs30, pga_rock, imt):
          
          if hypo_depth > 100:
              hypo_depth = 100
          delta = 0.00724 * 10 ** (0.507 * mag)
          R = np.sqrt(rrup ** 2 + delta ** 2)
  
          s_amp = self._compute_soil_amplification(C, vs30, pga_rock, imt)
  
          mean = (
              # 1st term
              C['c1'] + C['c2'] * mag +
              # 2nd term
              C['c3'] * hypo_depth +
              # 3rd term
              C['c4'] * R -
              # 4th term
              g * np.log10(R) +
              # 5th, 6th and 7th terms
              s_amp
          )
  
          return mean
docs: Compute mean according to equation 1, page 1706.