By Jhasua Razo, Amy O’Kruk, Annette Choi, CNN(CNN) — A powerful 7.4 magnitude earthquake struck western Colombia on Monday, killing scores and severely damaging thousands of buildings. Numerous buildings have been essentially razed to the ground or severely damaged, particularly in the major cities of Cali and Pereira. Julio Fierro Morales, director of the Colombian Geological Service, noted that western Colombia lies along a subduction zone, where one tectonic plate slides beneath another. “Among the historical precedents is the earthquake that occurred on November 23, 1979, with a magnitude of 7.2.” Quakes such as Monday’s in Colombia are measured on a magnitude scale.