Earthquakes in Lima and Peru
Scientists have developed a theory, called plate tectonics, that explains why most earthquakes occur. According to this theory, Earth's outer shell consists of about 10 large, rigid plates and about 20 smaller ones. Each plate has a section of Earth's crust and a portion of thick layer of hot rock below the crust. The plates move slowly and continuously. They collide, move apart or slide past one another. These movements finally can cause earthquakes.
Peru is situated along the boundary of two tectonic plates: the Nazca Plate and the South American Plate. The interface between these two plates is located near the Peruvian coast. At a rate of about 60 mm per year the South American Plate is moving towards the Pacific Ocean over the Nazca Plate. That may not sound a lot but it is enough to put huge strain on the Earth's crust. The pressures are periodically released through earthquakes.