There have been hundreds of aftershocks from Friday's 5.1 earthquake in La Habra, which experts said is what they expected.
The aftershocks are declining in frequency. The largest was a 4.1 temblor that hit Rowland Heights on Saturday afternoon. Many of the smaller ones likely were not felt.
Caltech seismologist Egill Hauksson said Saturday that scientists can't predict where earthquakes will go.
"We just have to watch what happens," Hauksson said.
There is precedent for earthquake aftershocks jumping faults. The Whittier Narrows earthquake, a magnitude 5.9, struck on the Puente Hills thrust fault system on Oct. 1, 1987. Three days later, a magnitude 5.6 aftershock hit on a different fault, Hauksson said.
That aftershock killed one person, twisted several chimneys and broke windows. Damage was reported in Whittier, Pico Rivera, Los Angeles and Alhambra.
Meanwhile, officials in northern Orange County spent Sunday assessing the damage from Friday's magnitude 5.1 earthquake.
The temblor caused damage to businesses -- mostly spilled merchandise and a few shattered windows. Friday night, dozens of dwellings were red-tagged as officials looked for structural damage.
Officials in the cities hardest hit -- Fullerton, Brea and La Habra -- have not yet released damage estimates. It appears the damage was modest, and there were no serious injuries.
About 50 residents were allowed back into their Fullerton apartment units, which had been red-tagged Friday night after the quake near La Habra, according to Fullerton Fire Battalion Chief John Stokes.
City building department inspectors were out in force Saturday to examine the 20 units at the building on Associated Road. They were deemed safe.
Elsewhere in the city, about 19 residents in six single-family homes across northern Fullerton remained displaced, Stokes said. Most appeared to be staying with friends or relatives after a nearby shelter at a La Habra community center was closed by the Red Cross because of a lack of requests for assistance.
About 13 water line breaks were reported in Fullerton after Friday's quake, including three ruptures under city streets. By Saturday night, they had all been repaired, Stokes said.
For most, the biggest headache was clearing away the aftermath of the quake, which was preceded and followed by a series of smaller nerve-rattling temblors that continued into Saturday. About 2:30 p.m., a shallow magnitude 4.1 earthquake hit the nearby Rowland Heights area, but no damage or major injuries were reported.
Friday night's shaking left scattered damage across the La Habra area, near the quake's epicenter, hitting houses, apartments and businesses as well as street lights that were left dangling precariously.
"From 20 to 30 businesses suffered broken plate-glass windows, many of them along Whittier Boulevard," La Habra Police Sgt. David Crivelli said. "There were also some apartments with stucco damage and leaking water."
By 10:30 p.m. Friday, residents had been evacuated from apartment units in the 2500 block of West Whittier Boulevard, the 400 block of North Idaho Street and the 700 block of West 1st Avenue. An L.A. Fitness center near Imperial Highway and Beach Boulevard had water running off the roof.
In Brea, officials were working to repair a broken water main.
Wayne Sass of Fullerton said a large picture covered with glass flew nine feet off the wall and shattered within inches of his terrified 9-year-old son. There was broken glass in every room and some cracks in the home's stucco, he said.
"We spent most of the night just trying to clean it up so the kids wouldn't wake up in the morning and be reminded of it," he said.
Their home on Canyon Drive had been without water since early Saturday, when a city crew shut off a broken water main. For most of the night, a geyser 75 feet tall spilled into a giant birdbath-like depression formed when the asphalt dipped, he said.