Whether the disastrous 2008 Wenchuan earthquake was or was not triggered by the reservoir behind the Zipingpu Dam is still under discussion (Kalpna and Gahalaut, 2010; Kerr and Stone, 2010; Zhou et al., 2010). Ge et al. (2009)presented a result suggesting that Zipingpu reservoir hastened the occurrence of the Wenchuan earthquake by tens to hundreds of years based on the calculation of the Coulomb stress change induced by the Zipingpu Reservoir at the initial rupture point of the Wenchuan earthquake. However, our recent similar work (Deng et al., 2010) indicated that Coulomb stress changes alone were neither large enough nor of the correct sign to promote this disastrous earthquake. The comment by Ge (2011) states that the reservoir-induced Coulomb stress change computed by us (Deng et al., 2010) omitted a crucial term (undrained response pressure) in calculating pore pressure and further infers that our conclusions are unsound.

We quite agree with Ge that the undrained response pressure is a crucial term in calculating pore pressure, and the pore pressure calculated in our publication actually included the undrained response pressure, which was described on p. 2807 of our paper (Deng et al., 2010). We admit that figure 3b of our paper just shows the diffusive pore pressure variations with time, which might have confused Ge. However, the calculated Coulomb stress change on the fault shown in figure 4 of our paper includes the contribution from the undrained response pressure as described on pp. 2806–2807 of our paper (Deng et al., 2010). It is very clear that our main conclusions are based on figure 4 instead of figure 3. Ge (2011) wrote that “initial zero ΔCFFs at all locations illustrated in their figure 4 suggest that the ΔP_u [undrained response pressure] term was not included in the calculation”; this is not true, because the date of time zero was set to be 1 October 2005, the impounding time of the Zipingpu Reservoir, which was described in our figure 3 (Deng et al. 2010)...