Aquifer Sensitivity to Earthquakes: The 1755 Lisbon Earthquake Key Points: Andrés Sanz de Ojeda1 , Iván Alhama2, and Eugenio Sanz2 • The recession coefficient α can be used as a parameter to measure 1Departamento de Ingeniería Minera y Civil, Área de Ingeniería del Terreno, Escuela de Ingenieros de Caminos y Minas, sensitivity of aquifers to earthquakes 2 • The hydrogeological phenomena Universidad Politécnica de Cartagena, Cartagena, Spain, Departamento de Ingeniería y Morfología del Terreno, Escuela induced by the 1755 Lisbon Técnica Superior de Ingenieros de Caminos, Canales y Puertos, Universidad Politécnica de Madrid, Madrid, Spain earthquake are described • The influence of the regional fractures, lithology, and recession The development of a theoretical analytical model leads us to consider the recession fi Abstract coef cients in these hydrogeological fi phenomena is analyzed coef cient as a useful hydrological parameter for studying the hydraulic impacts of an earthquake on spring flow in terms of the increase of persistent discharges and the overall alteration of springs. Both the inertia of the aquifer emptying and the increased pore pressure in the lower part of the aquifer caused by the earthquake contribute to maintaining the discharge of persistent springs. Abundant information on the hydrological phenomena induced or modified by the 1755 Lisbon earthquake (M ∈ [8,9]) and its relationship with present‐day knowledge of the geology and hydrogeology of Portugal and Spain, as Correspondence to: fl E. Sanz, well as Spanish spring statistics, have allowed us to identify the factors that most in uence the
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