The strongest aftershock since Chile's devastating earthquake rocked the South American country Thursday as President Sebastian Pinera was sworn into office.

The 6.9-magnitude aftershock was stronger than the quake that destroyed the Haitian capital on Jan. 12.

Aftershocks with preliminary magnitudes of 5.1, 7.2, 6.9 and 6.0, respectively, rocked Chile throughout the inauguration.

Chile's new president urged coastal residents to move to higher ground as congress was evacuated from the capital.

There were no immediate reports of damages or injuries but the temblor — and at least three other aftershocks — strongly swayed buildings — shook windows and provoked nervous smiles among the dignitaries attending Pinera's inauguration at the congressional building in coastal Valparaiso.

The biggest aftershock happened along the same fault zone as Chile's magnitude-8.8 quake on Feb. 27, said geophysicist Don Blakeman at the U.S. Geological Survey in Golden, Colorado.

"When we get quakes in the 8 range, we would expect to see maybe a couple of aftershocks in the 7 range," he said.

Blakeman said Chile now can expect to feel "aftershocks of the aftershock."

"It's not a sign of anything different happening. But what does occur when you get these large aftershocks, typically we have a whole series of aftershocks again," Blakeman said.

Bolivian President Evo Morales seemed briefly disoriented and Peru's Alan Garcia joked that it gave them "a moment to dance."

Outgoing President Michelle Bachelet arrived in an open limousine, followed by Pinera, who entered the hall of Congress to loud applause, shaking hands with politicians and dignitaries, and then swore his oath as president.

Bachelet said before the ceremony that she's leaving Chile in good shape, having already resolved a number of the country's most urgent needs in the wake of the February quake.

"I'm leaving office with sadness for the suffering of our people, but also with my head held high, satisfied with what we have accomplished," the socialist president said as she prepared to hand over the government to the first right-wing president to be elected in 52 years.

Bachelet led a "Viva Chile" cheer and then delivered a long goodbye from the presidential palace, La Moneda, where she marched with the palace guards and lingered with a passionate crowd in the plaza outside. Supporters waved socialist-party flags and pressed forward to shake her hand, give her flowers and even caress her face.

"We are handing over to the new government a country that is politically and socially stable, respected internationally and with authorities who have strong credibility," she added in her farewell address Wednesday night.

Meanwhile, Pinera was going right to work. A billionaire investor, Harvard-trained economist and airline executive with little patience for bureaucracy, he asked that pomp and circumstance be mostly set aside at his inauguration. Instead, Pinera planned a brief lunch with foreign dignitaries after the ceremony, and then a working visit to coastal Constitution, where the Feb. 27 tsunami killed many and destroyed the scenic downtown.

After meeting with survivors, he planned to fly back to the capital, address citizens from a balcony of the presidential palace and then hold a late-night strategy session with his Cabinet, dominated by business executives and technocrats.

Pinera had vowed on election night to make Chile "the best country in the world," spending billions to accelerate economic growth, create a million jobs in four years and combat crime, among other things.

Now, reconstruction is his top priority.

Last month's 8.8-magnitude earthquake, one of the strongest recorded, killed 500 identified victims and possibly hundreds of others; destroyed or heavily damaged at least 500,000 homes; and broke apart highways and hospitals. Repairing infrastructure alone will cost $5 billion, and overall recovery costs could soar above $15 billion.

Pinera's victory ended a 20-year run for the leftist coalition that led Chile back to democracy after the dictatorship of Gen. Augusto Pinochet, and puts the country's relatively small business elite directly in power, heralding many changes in Chilean society.

One small but telling change is his administration's new logo, which incorporates Chile's traditional coat of arms and its "by reason or force" motto, long used by Chile's military. The leftists had tried to change it to "by the force of reason," but never succeeded.

Pinera's campaign inspired voters hungry for change, even as he promised to maintain social programs created by Bachelet, who leaves office with 84 percent approval ratings.

But the new president lacks a legislative majority, so compromises with leftists will be a must, and restive unions have threatened crippling strikes if Pinera insists on his promise to privatize part of the state-run Codelco mining company, which provides much of the governnment's revenues.

The devastating 8.8-magnitude earthquake has changed the political situation, at least for now.

Leaders of the center-left coalition, which earlier rejected the idea of a national unity government, have moderated their tone and promised legislative support for Pinera's reconstruction plans.