Post‐seismic permeability change in a shallow fractured aquifer following a M_L 5.1 earthquake (Fourbanne karst aquifer, Jura outermost thrust unit, eastern France)

Following a M L 5.1 earthquake in eastern France, a post‐seismic 12‐day long electrical conductivity increase was recorded in the water discharging from a karst aquifer located 3 km from the epicentre. We attribute this to a permeability enhancement which allowed long‐residence time water from low‐permeability fractures located in the saturated zone to be expelled. The permeability enhancement shows that shallow aquifers can be significantly deformed for several days by moderate magnitude earthquakes.