A powerful quake rocked the area on Wednesday afternoon.
The 5.4 quake hit at a little before 4:53 p.m. about 13 miles north-northwest of Borrego Springs, according to the U.S. Geological Survey (USGS). Original estimates said the temblor was a 5.9 but that figure was later downgraded.
San Diego State University professor emeritus and geologist Pat Abbott said that he believed that this was a "new" quake, not an aftershock of the Easter quake that hit just south of the U.S. border in Mexicali and was measure at magnitude 7.2.
Abbott said that he believed that because he suspected the earthquake shook along a different fault line -- the San Jacinto -- than the Mexican quake.
"And that's what I would call this one, a trigger quake because we are off the Easter fault trend. We moved up on to the north and over to the east and onto a totally separate fault," Abott said.
The quake lasted quite some time, which is what gives it the large magnitude, Abbott said.
There were spotty reports of minor damage around the county, with people saying that items had fallen off shelves or that glasses had broken.
Closer to the quake, a rockslide was reported near Palm Springs, and a picture was circulating of dust kicked up by the slide.
Calfire reported a rock fell 1000 feet leaving a small crater on Old Hwy 80 near Campo at about 5:30 p.m. According to the California Highway Patrol, road crews were sent out to check the entire grade of Montezuma Valley Road near the intersection with San Felipe Road, where residents reported that large boulders about 18 inches in diameter had come down the hillsides and were on the roadway.
A bartender at Carlee's Place in Borrego Springs, Tony Wann, said the quake knocked glasses off shelves but that they did not break, nor was there any damage to report. He said shopkeepers and tourists came out of businesses briefly, then returned to the stores after the shaking stopped.
San Diego Fire Rescue spokesman Maurice Luque said no damage had been reported, nor had any injuries been blamed on the earthquake.
There have been several magnitude 5.0-plus quakes reported in the area of Borrego Springs, with a 6.8 shaking that region in 1968, according to research geophysicist Frank Vernon of the Scripps Institution of Oceanography.
Local
"This quake felt much stronger than the earlier Mexicali quake," Oceanside resident Nathaniel Ames wrote to NBCSanDiego. "My wife and I, in Oceanside (north part), felt a very sharp initial jolt and then a back and forth rolling motion, whereas the Mexicali quake was a much gentler rolling quake, as felt here in the Oceana part of Oceanside."
Twitter and other social media outlets were soon boiling with comments about the quake.
"Big quaking in Escondido," tweeted @howlingpoint. "Oh geeze! That is huge! Earthquake!" posted KKsWebs2 on Twitter.
"I was updating my Twitter and Facebook page about my new blog posts, then I felt and watch my room shake!" posted Francis Dela Cruz on Facebook. "Oh, well, I tweeted about the earthquake instead... I think it's more interesting and timely than my blog. Haha"
"Lemon Grove! the house shook for just a second or two, but it was a hard shake!" seconded Jazmin Randrup on Facebook. "It scared me!"
Oceanside, however, was not the furthest the quake was felt. Colleagues at NBCLosAngeles in Burbank said they, too, felt the quake.
"I was talking on the phone with my sister in Moreno Valley (Riverside County) when she started yelling, 'Earthquake!' " Onnye Chamberlain e-mailed to NBCSanDiego. "A few minutes later I felt it!! It was so weird to have it travel from one point to another so quickly."
Since that initial quake, there have been four aftershocks of magnitude 3.0 in the same area, according to the USGS.
