Hydrogeology
The Gran Lima aquifer consists of Quaternary alluvial deposits of Rimac and Chillon valleys. These deposits are characterized by the presence of boulders, gravel, sand and clay interspersed in layers and/or mixed. Another aspect is the presence of groundwater level that changes during the project area. In particular, the groundwater is located near the harbor zone in correspondence to the first part of line 2 and to the total of line 4.
Tectonics and Seismicity
Perù is located on the east coast of the Pacific in so-called “Cinturon de Fuego del Pacifico” area that due to the interaction between the South America plate and Nazca plate, which generates a subduction zone near the Perù coast, represents one of the most active earthquake zones in the world. For this reason, a study of seismic risk of the project area was carried out in order to evaluate the correct seismic parameters. This study is based on seismic hazard determination which is defined as the exceedance probability of a determinate ground motion intensity value due to an earthquake in a given location and during a defined time period. According to this study (with deterministic and probabilistic methods) and taking into account the spatial variability of the seismic action, the maximum value of the peak ground acceleration equal to 0.40 g has been obtained. For the evaluation of seismic design parameters five representative zones, each having different geophysical and geological characteristics, were considered (Table B).