Another Chile earthquake. Presidents, Evo Morales of Bolivia (L), Fernando Lugo of Paraguay (2nd R) and Alvaro Uribe of Colombia (R, back to camera), react with other guests to a strong 7.2-magnitude aftershock that shook the region a few minutes before the inauguration of Chile's president-elect Sebastian Pinera at the Congress in Valparaiso on Thursday.

In Constitucion, heavily damaged in the 8.8-magnitude quake on Feb 27, residents scrambled for the hills on Thursday after the navy issued a tsunami alert for the mainland, but it was later called off.

Thursday's aftershocks were an unsettling reminder of the earthquake that killed nearly 500 people and damaged infrastructure across much of south-central Chile, threatening Pinera's election pledges to boost economic growth to 6 percent a year and to create a million jobs.

"It's time to get to work," Pinera said after taking office, adding that he had ordered his interior minister to personally oversee the recovery work of state emergency office Onemi, heavily criticized for its handling of the earthquake and ensuing tsunamis that devastated coastal villages.

Chileans hope that Pinera, a Harvard-trained economist, can use his business acumen to help one of Latin America's most stable economies rebound from the devastating erthquake.

"The main challenge is to identify priorities to swiftly start the reconstruction effort. That will be the key variable that will be evaluated during his administration," said Alberto Ramos, senior economist with Goldman Sachs in New York.

"This could be the Katrina of President Pinera ... in terms of how the population perceives the relief and reconstruction effort," he said, referring to the powerful hurricane that struck New Orleans in 2005. The slow relief effort damaged U.S. President George W. Bush's popularity.

While mines were mostly unscathed in the world's top copper producer, the February quake seriously damaged Chile's key wine, fish and paper pulp industries.

Some analysts see the damage shaving 0.5 to 2.0 percentage points off this year's economic growth, while others are holding to their original GDP forecasts of around 5 percent.

State-owned copper miner Codelco, the biggest copper miner in the world, said none of its mines were damaged in Thursday's aftershocks. One, a powerful magnitude 6.9 centered about 124 km (80 miles) south-west of the capital, was nearly as powerful as the quake that devastated Haiti in January.