More than 200 dead in Colombia earthquake, with rescuers unable to reach epicenter yet

It has now been more than 36 hours since Colombia was struck by a deadly 7.4-magnitude earthquake, and rescue workers are racing to reach people trapped underneath debris and rubble.

Historically, the first 48 to 72 hours after a quake are widely regarded as the “golden” window to reach people buried alive — after that period the chances of survival without a water source diminishes rapidly.

Some rescue teams follow a “rule of fours,” which assumes that trapped people can survive four minutes without air, four days without water and four weeks without food.

Emergency responders are racing to find survivors after a magnitude 7.4 earthquake struck western Colombia, killing more than 200 people, according to a CNN count based on reports from officials. The government declared a national disaster and world leaders have offered assistance.