A series of aftershocks shook the quake-weary New Zealand city of Christchurch on Monday, bringing down at least one building and briefly trapping two people inside a damaged church.

Power was cut to about 10,000 homes in the city's eastern suburbs, and dust billowed from the cordoned-off city center devastated in February's major earthquake. More than 80 percent of the building's in the central city's "red zone" were damaged in that disaster, including more than 700 that cannot be salvaged.

"We are being enveloped with dust. It is very, very scary," Christchurch Mayor Bob Parker told New Zealand's National Radio.

Rocks tumbled from hills in the eastern suburbs, where the earthquake also pushed up a watery silt that is created during some quakes, a process called liquefaction. The city's airport was closed so the runways could be inspected but there did not immediately appear to be damage, Air New Zealand spokeswoman Marie Hosking said.

Ten people have been taken to hospitals with minor injuries from falling debris, an ambulance service said.

All across Christchurch, people fled buildings in panic when a 5.2-magnitude quake struck during lunchtime; just over an hour later, a 6.0 was recorded, according to the U.S. Geological Survey.

The city has been shaken by thousands of aftershocks since the 6.3-magnitude quake killed 181 people on Feb. 22. Like that temblor, Monday's two biggest quakes were very shallow, both around six miles (10 kilometers) deep.

The shallow depth of the February quake and its proximity to the city helped magnify its destructive force.

"I acknowledge that this has been a setback for Christchurch and its people, but it does not lessen our resolve to rebuild," Prime Minister John Key told reporters.

Two men who were salvaging windows from St. John's Church became trapped after one of Monday's aftershocks brought down the building's facade, the last wall standing after February's quake. Police said they were rescued and taken to a hospital with cuts and bruises.

Another nearby building collapsed, but no one was inside.

The mayor said more masonry fell from the badly damaged Christchurch Cathedral, sending up large clouds of dust.

Fire Service spokesman Dan Coward said they were inundated by calls about burst pipes. He added that many people were "freaked out" by the latest jolts.

People attending inquest hearings for victims of the February earthquake reportedly bolted from the Riccarton Park Function Center when Monday's quakes struck. Others fled from buildings at Canterbury University and the Westfield Riccarton Mall, which also suffered heavy damage in February.

Canterbury law student Jennifer Jones was on the second floor of the library when the quake hit.

"It started off not too bad but then all the books started flying off the shelves. You've got 11 floors above you so everyone got out pretty quickly," she told the Stuff news website.