Scientists are calling the earthquakes that struck near Yorba Linda Tuesday night and Wednesday morning are being called a "quake swarm," or a "double quake" because there were two temblors -- a 4.4 and 4.5 -- that were similar in size. Patrick Healy reports from Caltech in Pasadena for the NBC4 News at 5 p.m. on August 8, 2012.
Back-to-back magnitude-4.5 and -3.4 earthquakes were reported Wednesday morning near Yorba Linda area, just hours after a magnitude-4.4 quake and several aftershocks were reported in the area.
Wednesday's earthquake was reported at 9:33 a.m. about one mile northeast of Yorba Linda. A magnitude-3.4 quake was reported at 9:51 a.m. in the same area.
"It's hard to tell if this was a quake or aftershock because they were in the same area and same magnitude, so I would call this a double-quake," said Dr. Kate Hutton, staff seismologist at Caltech. "I would call this a cluster or quake swarm. We can expect to see more small quakes-aftershocks."
By 12:30 p.m., more than 10 quakes had been reported in the area:
NBCLA Facebook page visitors reported shaking in Santa Clarita, Carson, Pasadena, Orange, Huntington Beach, Anaheim and other locations.
"It felt bad here in Anaheim -- like a big truck hit the building," wrote Facebook visitor Leo Sanamaria.
The shaking was something with which newly acquired Dodger Shane Victorino didn't have to deal in Philadelphia. The ex-Phillies player tweeted, "Why is the hotel shaking????? Could u say #Earthquake____________? Welcome to #LA!"
The shaking followed Tuesday night's quake, which occurred in the same area at about 11:23 p.m.
There have been no reports of injuries or damage.
The location of the quake center was near the Whittier Fault, but the quakes could be occurring on an unmapped fault.