def _compute_site_class_term(self, C, vs30):
        """
        Compute nine-th term in equation 1, p. 901.
        """
        # map vs30 value to site class, see table 2, p. 901.
        site_term = np.zeros(len(vs30))

        # hard rock
        site_term[vs30 > 1100.0] = C['CH']

        # rock
        site_term[(vs30 > 600) & (vs30 <= 1100)] = C['C1']

        # hard soil
        site_term[(vs30 > 300) & (vs30 <= 600)] = C['C2']

        # medium soil
        site_term[(vs30 > 200) & (vs30 <= 300)] = C['C3']

        # soft soil
        site_term[vs30 <= 200] = C['C4']

        return site_term
def _compute_site_class_term ( self , C , vs30 ) : site_term = np . zeros ( len ( vs30 ) ) site_term [ vs30 > 1100.0 ] = C [ 'CH' ] site_term [ ( vs30 > 600 ) & ( vs30 <= 1100 ) ] = C [ 'C1' ] site_term [ ( vs30 > 300 ) & ( vs30 <= 600 ) ] = C [ 'C2' ] site_term [ ( vs30 > 200 ) & ( vs30 <= 300 ) ] = C [ 'C3' ] site_term [ vs30 <= 200 ] = C [ 'C4' ] return site_term
Compute nine-th term in equation 1, p. 901.