Fluid flow and seismicity pattern: Evidence from the 1997 Umbria‐Marche (central Italy) seismic sequence

We model the spatial and temporal evolution of seismicity during the 1997 Umbria‐Marche seismic sequence in terms of subsequent failures promoted by fluid flow. The diffusion process of pore‐pressure relaxation is represented as a pressure perturbation generated by coseismic stress changes and propagating through a fluid saturated medium. The values of isotropic diffusivity range between 22 and 90 m2/s. The calculated value of anisotropic diffusivity (Daniso= 250 m2/s) is largest along the average strike (N140°) direction of activated faults. Our results suggest that the observed spatio‐temporal migration of seismicity is consistent with fluid flow.