  We develop a general method to compute correlation functions of fractional
quantum Hall (FQH) states on a curved space. In a curved space, local
transformation properties of FQH states are examined through local geometric
variations, which are essentially governed by the gravitational anomaly.
Furthermore, we show that the electromagnetic response of FQH states is related
to the gravitational response (a response to curvature). Thus, the
gravitational anomaly is also seen in the structure factor and the Hall
conductance in flat space. The method is based on iteration of a Ward identity
obtained for FQH states.
