Here's some of the first tweets on the incident from Peru.
@froncal1 (Lima, Peru): Hubo un temblor y me quedé sentada!!! (There was an earthquake and I was sitting!!!)
@Camuss (Lima, Peru): te dije que era temblor... http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2009cpa1.php (I told you I was shaking...)
@Karikuy (Lima, Peru): just experienced a 5.5 earthquake that is said to have been off the coast of Peru, funny, I thought it was just a large truck passing by.