Sea-Level rise and subsidence/Uplift processes in the Mexican South Pacific Coast

Along the Mexican South Pacific coast, seismic activity can generate a relative and instantaneous fall in sea-level with differential recovery times along the coast that, considering the occurrence of new coseismic coastal uplifts, can induce recurrent hydrodynamic behaviors. These behaviors could be important for coastal processes, such as tide inlet stability or beach erosion and accretion rates. To obtain a first approximation of this phenomenon, four tide gauge records were analyzed. Results showed a relative fall in sea-level at two tide gauge stations: Acapulco (25.3 cm) and Puerto Angel (14.6 cm). By applying derived sea-level trends, it was observed that the needed time to recover the mean sea level before the events occurred was 25.1 y for Acapulco and 82.9 y for Puerto Angel. If the apparent increment of global sea-level trends obtained from satellite altimetry is considered, recovery times could be reduced by 3.1 and 36.9 y for Acapulco and Puerto Angel, respectively. In Puerto Angel, this implies a significant reduction in the probability of the occurrence of a new coseismic uplift before the recovery of mean sea level. To make generalizations for the Mexican South Pacific coast, an auxiliary tool, the Recurrent Hydrodynamic Behavior Graph, was developed to facilitate analysis of the phenomenon and assist with decision making in coastal projects.