Another earthquake struck the Reno area late Friday night, dumping cans off shelves, knocking pictures off walls and sending rocks off hillsides of the eastern front of the Sierra Nevada.

There were no immediate reports early Saturday of injuries or major property damage.

The U.S. Geological Survey reported the 4.7-magnitude temblor hit at 11:40 p.m. and was centered six miles west of Reno near Mogul, where a swarm of more than 100 quakes rattled the area on Thursday. The biggest of those was a 4.2 event.

Friday's 4.7 quake originally was estimated to be 4.9, the USGS said, but revised downward after more details were available.

A 3.5 aftershock was recorded at 12:29 a.m. Saturday, followed by at least 30 smaller ones, the USGS said.

The initial quake was felt 30 miles north in Portola, Calif., and at least 45 miles south near Stateline, Nev., on Lake Tahoe's south shore.

The temblor cracked walls in northwest Reno, broke lawn watering lines and damaged a wooden flume built along the Truckee River in the late 1800s to carry lumber from Lake Tahoe down the mountain to Reno. Emergency crews responded to the flume break near Mogul but there were no immediate reports of flooding.

It was the strongest quake to shake the city since hundreds of much smaller events have been recorded in the area since the end of February.

Jars of mayonnaise, bottles of ketchup and shampoo fell from shelves at a Wal-Mart store in northwest Reno. It caused the overhead televisions to sway at a sports bar in neighboring Sparks, 11 miles east, where bartender Shawn Jones said the rumble was significantly stronger than Thursday's event.

"The bottles were shaking so I sent everybody outside," he said.

Shirley Dippel of Sparks said the quake pushed her bed against the wall.

"That's the best one I've felt so far, and I've been here 44 years," Dippel told the Reno Gazette-Journal.

High school senior Alex Hill said it was "scary."

"It is one of those things you know that happens," he said, "but you never imagine it happening in your area."

Scientists said earlier Friday that Reno faces a "small increase" in the chance of a major earthquake in the aftermath of the seismic activity.

"The persistence of this particular earthquake sequence slightly increases the probability for a significant earthquake in west Reno," said a statement from the Nevada Seismological Laboratory at the University of Nevada, Reno.

"However, the occurrence of additional earthquake activity in the Mogul area cannot be predicted or forecast," it added.