The Popayán earthquake of 1983 was a highly destructive, high mortality event (mb = 5.5). It was probably caused by the rupture of the Pubenza fault, a NNW-trending feature mapped on the basis of cracks in pavements and breaks in underground water pipes. Significant damage to modern construction was confined to an area within 1 km of the fault trace in the urban area. Near-field observations of upthrow and other effects suggest that the earthquake featured a high-amplitude pulse of the order of 1 g in the vicinity of the fault trace. Losses were of the order of $500 million.