At a flattened apartment block known as Los Cocos in northern Venezuela, civilians toiled with little support to pull the living and the dead from the rubble. In neighboring Colombia, when residential towers in Cali collapsed, ?officials poured in to help.

Devastating earthquakes weeks apart in Venezuela and Colombia have exposed sharply different government capacities to respond to disaster, according to witnesses in both countries, aid workers and a security firm.

In Venezuela, civilians led rescue efforts after two back-to-back quakes in late June, finding survivors and victims as confusion, lack of equipment and delayed orders stymied the official response.