One million people had to leave their homes and at least 11 people died when the 8.3-magnitude quake hit on Wednesday night.
In the coastal town of Coquimbo, waves of 4.7m (15ft) hit the shore. Small tsunami waves hit as far away as Alaska.
President Michelle Bachelet visited Coquimbo on Thursday.
Tsunami waves also hit the coast further north and south of the quake's epicentre, with waves half a metre higher than usual as far north as La Punta.
The quake - the strongest in the world this year - lasted for more than three minutes and there were dozens of aftershocks.
Gloria Navarro, who lives in the coastal town of La Serena, said people were "running in all directions".
"Everything is a mess," restaurant owner Melisa Pinones told Reuters from the city of Illapel. "It was a disaster, a total loss."
Across parts of central Chile, residents began clearing up on Thursday after what was the country's sixth most powerful recorded earthquake.
Large parts of the sea front in the fishing village of Tongoy were destroyed, and more than 500 homes were badly damaged across the region, according to emergency response teams.
Close to 90,000 homes remain without electricity.
Emergency powers mean aid will reach Coquimbo quicker, and allow troops to be deployed on to the region's streets.
President Bachelet paid tribute to people's response, saying that the death toll, "while unfortunate, was not very high considering the strength of the earthquake".
The US Geological Survey (USGS) said the tremor struck off the coast of Coquimbo, 46km (29 miles) west of the city of Illapel at 19:54 local time (22:54 GMT).
The USGS said it was at a depth of 25km, while Chilean seismologists calculated its depth at 11km.
Small tsunami waves were felt along the west coast of the US and Canada. A one-metre (3ft) wave also reached in Hawaii.
The earthquake struck as thousands of Chileans were travelling to the coast ahead of a week of celebrations for independence day.
President Bachelet said some of the official festivities would be cancelled.
Source: BBC