Oscar and Maria Alicia Flores were asleep on green cots next to their two children in a shelter for those left homeless by Thursday's big temblor when the Earth shook again early Sunday.
Children screamed as tiles fell from the darkened ceiling of the Whittier Community Center's gymnasium as the aftershock hit.
Red Cross volunteers hustled 67 panicked people to an adjacent field, where they stayed while officials inspected the building.
Two men at the center suffered possible heart attacks, and a pregnant woman thought she was having a miscarriage.
Maria Alicia said she thought it was "the big one."
Oscar said he wasn't sure, but he knew he wanted to get out.
"Like all people, I have phobias," he said, "and one of them is the fear of being crushed beneath a wall."
The Floreses and the others were allowed back into the shelter about 7 a.m., where they were joined during the day by at least 60 more refugees from the aftershock.
It was the second time in four days that Whittier residents had experienced the destructive force that shattered stores, homes and other buildings.
Officials said Sunday's temblor, which measured 5.5 on the Richter scale, caused the most damage to buildings that had marginally survived Thursday's 6.1 shake.
The hard-hit Uptown Whittier business district was again closed by police shortly after the new jolt so city workers could remove debris from the sidewalks of Greenleaf Avenue and the buildings could be re-inspected. Many business owners had spent Saturday installing new glass and cleaning up, only to have to begin again on Sunday.
The Uptown area was reopened in the late afternoon.
City Manager Thomas G. Mauk said at least 50% of the buildings in the 24-block area were unsafe, and he said damage to Whittier businesses and private property could exceed $50 million to $60 million.
Residents, particularly those living in the area just north of Uptown, were back out on their front yards Sunday, checking out the damage and wondering when the shaking would stop.
Maria Celia Fuentes, 50, planned to spend Sunday night on the lawn along with the 17 members of her family who share a home on Bright Avenue, one block from Uptown.
Fuentes, 50, complained of pain in her legs as she sat on a piece of carpeting beneath a shade tree.
"It was the fear that did it," she said with certainty.
But Fuentes said she was reluctant to seek medical attention, because she knew what she would be told--stay in bed.
"I don't want to be lying on a bed when another earthquake hits," she said. "But then, I don't feel safe anywhere."
Patricia Ruiz, who lives in the same house, said she bolted from her bed when she felt the temblor and hurdled a five-foot porch ledge to run out into the street.
A few blocks away, on Newlin Avenue, the already homeless Ana and Luis Alberto Rodriguez recalled their panic during the aftershock, which interrupted their night spent under a sheet stretched across the lawn of a relative's home.
The Rodriguezes and their three children lay petrified, clutching each other atop a blanket, as they felt the ground jolt and gradually rumble into stillness.
"I was afraid, but it's better to be outside," said Ana, adding that the family abandoned their Whittier apartment after Thursday's earthquake because they feared it was unsafe. They said they do not intend to return.
Elsewhere on Bright Avenue, Rod Rodriguez (no relation to the other family) surveyed the scene from a chair parked under his shaded front lawn. His water service was restored Saturday after being out since Thursday, and he had been looking forward to a shower and a shave Sunday morning.
"You think you've got it licked and it comes right back down around your ears," he said.
Just a few hours after Sunday morning's jolt, the streets of Whittier were clogged with traffic and curiousity seekers with cameras. Some residents, trying to rebuild their shattered homes, resented the intrusion.
"How would they feel if it was in their back yard?" one asked.
The onlookers were inspecting new damage, which included collapsed porches at some homes, and the deteriorating buildings in the business district.
At Tip Tap Siam, a Thai restaurant Uptown, the front plate glass window was smashed and owner Wasu Srivilai sat on a shaded curb across the street to keep an eye out for looters.
As she was discussing her loss, a white pickup truck pulled up and Patrick Latronica yelled out an offer to board up the window.
"How much?" she asked. "We've already had one guy come by."
"We can do it cheaper," Latronica said.
"Fifty dollars," he said, and Srivilai agreed. Latronica had already boarded up two windows by 10 a.m. and said business was good.
Officials at Presbyterian Intercommunity Hospital in Whittier reported that 50 people were treated for quake-related injuries Sunday and eight were admitted. The two heart attack victims at the community center were expected to survive; the miscarriage proved to be a "false alarm," the officials added.
The Red Cross opened a second shelter at California High School in Whittier.
"We're doing a tremendous amount of psychological counseling here," said Barbara Haller, public information officer for the shelter. "People can handle one, but they can't handle two."