The borough was the hardest hit by the 1985 earthquake with 258 buildings completely crumbled, 143 partially collapsed and 181 were seriously damaged. The result was the loss of 100,000 residents, just in the historic center. Another area with major damage was Colonia Roma with a number of buildings collapsing completely. Even areas that did not suffer significant damage, such as Colonia San Rafael, were affected when homeless from other parts of the borough moved in, or Colonia Condesa, when wealthier residents moved out. Because of the rent situation, most of the damaged structures were never fixed or rebuilt, leading to slums or garbage-strewn vacant lots. As late as the 2000s, buildings damaged from the event have collapsed. In 2003, the city government expropriated sixty four properties thought to be in danger of sudden collapse due to damage suffered nearly 20 years earlier after a collapse of an apartment building in Colonia Vista Alegre, but in 2010 an apartment building partially collapsed in Colonia San Rafael, due to the same cause. Since the quake, the borough has invested in its own early warning system, which was created for it by UNAM.