A Mw 6.2 magnitude earthquake occurred at 1:19 pm on January 25th, 1999 in the Colombian western central area. It was produced by a shallow fault in a region with a strong relief located in the western slope of the Central Cordillera and on the Quindio alluvial fan, where the cities of Armenia and Pereira are located. This is a densely populated region with an important agriculture activity. THe effects on human lives, infrastructure, environment and economy make this earthquake one of the most severe in Colombia; 32 municipalities where affected, 13 with more than 10 000 inhabitants. The death toll was 1185; 32 405 houses were destroyed and 243 of a total of 521 where damgaged. The economic losses sums up at least 2,5 % of NGP (1998). Seismic waves triggered landslides, crack formation, mudflows and variations in water sources in an area of about 1500 km2. This contribution was prepared from information available in publications and report of several national and international institutions and from information directly collected in the field by OSSO technical and scientific staff.