The Rosas-Julimito Fault is a rather short section of about length , of which have active tectonic movement . The fault section parallels the Cauca-Almaguer Fault , which is one of the largest older fracture zones in western Colombia . The Rosas-Julumito Fault runs about west of the city of Popayán . The fault crosses the Pliocene-Pleistocene Popayán Formation , which consists of pyroclastic flow , mud flow and ash-fall deposits . It is believed that either the Rosas Fault or the nearby Julumito Fault ( less than to the west ) produced the earthquake of March 31 , 1983 that partially destroyed the city of Popayán . The fault is noted in the south of the Cauca Department
earthquake of March 31 , 1983
1983 Popayán earthquake
Romeral Fault System