In photos: evacuation after strong quake

Mining in the world's No. 1 copper producer did not appear significantly interrupted.

State-owned miner Codelco and other major copper companies reported no harm to workers or mines, saying that operations in northern Chile were normal. Still, the massive Collahuasi mine evacuated workers so they could be with their families.

President Michelle Bachelet declared the northern coast a disaster zone, promising troops and police reinforcements to maintain public order while damage was repaired after landslides blocked roads.

Lauding Chile's initial response to the quake, Bachelet said in a televised address: "The government will work for as long as necessary to confront this emergency."

Chile is one of the world's most earthquake-prone countries.

A magnitude-8.8 quake and ensuing tsunami in central Chile in 2010 killed more than 500 people, destroyed 220,000 homes, and washed away docks, riverfronts and seaside resorts.

The strongest earthquake ever recorded on Earth also happened in Chile - a magnitude-9.5 tremor in 1960 that killed more than 5,000 people.

Hundreds of earthquakes have shaken Chile's far-northern coast in the past two weeks, keeping people on edge as scientists said there was no way to tell if the unusual string of tremors was a harbinger of an impending disaster.

The unnerving activity began with a strong magnitude-6.7 quake on March 16 that caused more than 100,000 people to briefly evacuate low-lying areas, although no tsunami materialized and there was little physical damage from the shaking.