RENO, Nev. (AP) _ More than 50 aftershocks were recorded on the west edge of Reno after an earthquake that shook cans off shelves, knocked pictures off walls and dislodged rocks on hillsides along the Sierra Nevada.
There were no immediate reports of injuries or major damage early Saturday from the magnitude 4.7 quake that hit at 11:40 p.m. Friday. It was the largest quake in a two-month-long swarm of tremors.
"The earthquake was strongly felt in west Reno and felt throughout the Reno metropolitan area," the University of Nevada, Reno's seismology lab said in a statement early Saturday.
The U.S. Geological Survey said Friday night's quake was centered six miles west of Reno near Mogul, an area rattled by a swarm of more than 100 quakes the day before. The strongest of those was a magnitude 4.2 that caused high-rise hotels to sway in the downtown casino district.
The strongest aftershock measured magnitude 3.7 and was recorded at 12:29 a.m. Saturday.
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 float timber from Lake Tahoe down the mountain to Reno. There were no immediate reports of flooding along the flume.
Jars of mayonnaise, bottles of ketchup and shampoo fell from shelves at a Wal-Mart store in northwest Reno. Overhead televisions swayed 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.
Ken Smith, a seismologist at the university lab, said the recent activity around Reno is unusual because the quakes started out small and continue to build in strength. The normal pattern is for a main quake followed by smaller aftershocks.
"If the pattern continues we may be looking at a larger event" in the Reno area, Smith said Friday. "We wouldn't be surprised to see it (swarm) end at any time and it also wouldn't be surprising to see a large earthquake. The bottom line is we don't know what will happen."
Reno's last major quake measured 6.1 on April 24, 1914, and awakened people as far away as Sacramento, Calif., said Craig dePolo, research geologist with Nevada Bureau of Mines and Geology.
On the Net:
U.S. Geological Survey: http://www.usgs.gov/
University of Nevada, Reno, seismology lab: http://www.seismo.unr.educ/
Copyright 2008 The Associated Press.