Hospital director Juan Urrutia said at least 117 people were treated there for injuries or panic.
Two sections of Tocopilla were evacuated, and schools were being used as shelters for those left homeless by the quake.
Chile's government said it was flying 500 emergency housing units to Tocopilla, along with a military hospital, medicine, and food. The housing was expected to be installed Thursday morning.
Electricity was restored in large areas of Tocopilla. Army trucks were distributing water to residents as supply was still cut off in most of the city.
In tiny Quillagua, with a population of around a hundred, one person suffered minor injuries and 15 houses were damaged.
In María Elena, 1,200 homes were damaged—or 70 percent of the city's total, authorities said.
Lagos Weber said about 170 people were taken to hospitals across the region, but that many of the injuries were not serious.
About ten road workers who had been trapped near Tocopilla when a section of a tunnel they were repairing collapsed were all rescued in good condition Thursday.
Chile's largest copper mines are in the quake area, and production was halted as electric power was cut for several hours Wednesday before being restored.
The nation is the world's largest copper producer.
Hundreds of residents slept in cars or tents in front of their houses. Schools were being used as shelters for those left homeless by the quake.
Officials said many are refusing to go to shelters, because they fear their homes will be looted if left unattended.
"We slept in the car, because we have to care for whatever the quake didn't destroy," resident Luis Porcel told the Associated Press.
At a badly damaged restaurant in María Elena Wednesday night, a dozen men drank beer by candlelight.
"What else can I do? I lost everything. So I'll just have a few drinks," said Samuel Araya, a 57-year-old miner and one of 7,000 residents of this town, which was once a nitrate mining center.
Blanca Pizarro said she took refuge under her kitchen table when the quake struck, and seconds later the roof collapsed on the table. "I'm alive by a miracle," she said.
The 7.7 magnitude quake Wednesday was so strong it shook the capital, Santiago, 780 miles (1,255 kilometers) away, and was felt on the other side of the continent in São Paulo, Brazil—400 miles (650 kilometers) to the east.
"I thought my last day had come when I saw the mountain shaking under a large cloud of dust," said Maria Ines Palete, a resident of Quillagua. "It was incredible."
The quake occurred in one of the most seismically active regions in the world, where the Nasca tectonic plate is shoving itself beneath the South American plate.
A 1939 quake in Chile killed 28,000 people, and in 1960, a magnitude 9.5 quake—the strongest recorded in the 20th century—killed 5,700 people. On June 13, 2005, a magnitude 7.8 quake near Tarapacá in northern Chile killed 11 people and left thousands homeless.
Copyright 2007 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.
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