Examiner.com reported on July 8, 2010:

Alaska is one of the most seismically active parts of the United States and early Thursday morning residents near Anchorage received a reminder of that fact. A magnitude 5.0 temblor stuck in the evening hours on Wednesday and was felt across the south-central area of the state.

Centered 50 miles north-northwest of Anchorage, the quake struck at 07:15pm and according to the U.S. Geological Survey (USGS) was at a depth of 12.9 miles below the surface.

The service said it had received reports of the temblor being felt as far away as Palmer and Valdez to the east and Skwentna to the west. Residents of Anchorage and Seward to the south also felt the shaking.

Being along the Pacific Ring of Fire, Alaska regularly experiences earthquakes although most are small and not felt. The boundary of the North American and Pacific tectonic plates that runs through south-central Alaska and the Aleutian Islands is where most of the activity occurs.

The Alaska Earthquake Information Center (AEIC) says that the state receives from 50 to 100 earthquakes a day. Three of the 10 largest earthquakes recorded in the world, all larger than magnitude 7.9, have been recorded in Alaska.

Magnitude 5.4 Earthquake Jolts San Diego...

A magnitude-5.4 earthquake rocked San Diego Monday, giving buildings and roadways throughout the county a good shaking for several seconds, causing a couple rockslides but leading to no immediate reports of injuries or structural damage. 

The temblor, centered about 13 miles north-northwest of Borrego Springs, struck at 4:53 p.m., according to the U.S. Geological Survey. The shaker was felt in Riverside County and as far north as Palmdale in northern Los Angeles County.

A rock slide was reported near the 14-mile marker of Montezuma Valley Road near San Felipe Road with several large boulders down, approximately a foot and a half in diameter.  Also, a large boulder, approximately 4 foot by 5 foot, fell 1000 feet from a cliff, bounced across Old Highway 80 and left a 3 foot by 1 foot deep hole in the 8-inch concrete near Buckman Springs Road. The rock had enough force to break two mature oak trees.

Oklahoma native Betty Hanson was enjoying a day at Imperial Beach. She told San Diego 6 she had never felt such a thing. "All of a sudden, it was like a shimmy -- and the water just went flat."

Fey Crevoshay, a Mexico City native, has felt her fair share of quakes. Crevoshay was inside her condo when this one hit. "First it really was up and down -- which is pretty scary -- and strong, getting stronger -- and the last part was side to side."

Christopher Head was at the top of a downtown hotel. "I was on the seventh floor of the Plaza Hotel. I was kicking a bag into my closet, and it started shaking."

The "earthquake hit pretty hard here," said San Diego 6 News viewer Mark Pankau from Ranchita, west of Borrego Springs.   "Horses got pretty upset.  Largest earthquake I have felt in a long time," said Pankau. 

The quake was felt over a wide area of Southern California and Northern Mexico.  The U.S.G.S has received reports of the quake being felt north of Los Angeles and in 29 Palms in San Bernardino County.  A few reports also came from Arizona and Nevada.

The San Diego Fire Department rolled all fire equipment out of the fire station bays. The procedure is routine when an earthquake is felt to make sure equipment is available if aftershocks cause damage to the bay doors or a power failure.

Geologist Pat Abbott says this earthquake is not an aftershock to the Easter Sunday 7.2 earthquake.   Wednesday evening's earthquake was along the separate San Jacinto fault line.

Abbott told San Diego 6, "I thought, 'Oh, oh! This is really going to be a very big earthquake' -- because it got off to such a fast start."

Abbott says aftershocks can be expected for several days.

Right after the quake El Cajon city spokesperson Monica Zech tweeted: "Felt it pretty strong here at El Cajon City hall in our 6 story building - upper floors had to use the stairwells to leave at 5pm."

The Laney family in Oceanside e-mailed San Diego 6: "Heard the quake before it hit, sounded like a garbage truck rumbling through our home.  Daughters quickly ducked down at the ends of their beds.  Dog not happy, cats unfazed."

Though the quake was widely felt across the county, the region's police and emergency-services agencies received no immediate reports of any problems resulting from the temblor. 

The shaker also jostled communities in the Riverside area and as far away as Palmdale in northern Los Angeles County. 

Darren Pudgil, spokesman for San Diego Mayor Jerry Sanders, said there had been no reports of damage, though the quake temporarily knocked out elevator service at City Hall, forcing many workers to use the stairs to exit the 13-story building. 

Gil Alexander, a spokesman for Southern California Edison, said the shaking was felt at the San Onofre Nuclear Generating Station, but was "not sufficient to lead to an automatic shutdown of the reactor." Inspectors looking over the facility had found "no indication of damage," Alexander added. 

At Palm Canyon Resort in Borrego Springs, cooking pans, glasses and other objects fell from shelves as the buildings rocked back and forth, but nothing broke, said Scott Elliott, the establishment's manager. 

"It was a strong hit," he said. "You could hear it coming -- a loud rumbling, like a truck." 

Celina Deldadillo, a waitress at nearby Kendall's Cafe, said she was about to leave her home to go to work when the temblor hit, startling her so much that she screamed. 

"It was scary," she said by telephone from her Palm Canyon Drive workplace, where boxes of cereal and other supplies fell to the floor as the building vibrated. 

Deldadillo added that the quake was the strongest she'd ever felt. 

"I know a lot of people are shaking now, like me," she said. "My heart's going, `boom, boom boom!"' 

USGS seismologist Kate Hutton told reporters at Caltech in Pasadena that the quake likely occurred in the San Jacinto fault zone, and it was followed by about two dozen small aftershocks, the largest a magnitude-3.6. 

She said the quake was likely not an aftershock to the magnitude-7.2 temblor centered near the Mexican border that rattled much of Southern California in early April. 

"This earthquake, probably, although it's pretty close in time after the April earthquake, it's probably not an aftershock because it's located in a different location," Hutton said. "But it probably is what we would call a triggered earthquake, because we're now thinking that the 7.2 earthquake in April changed the strain slightly in the San Jacinto fault area and the Elsinore fault area, and it increased the number of small earthquakes that were happening there. And this is an example of an earthquake that's like that." 

Hutton said residents should take today's quake as a warning to be prepared for temblors. 

"The best way for people to look at this earthquake is that it's a drill," she said. "... If this one had been the big one, what would I have done? Would I have been prepared? Would I have had my supplies, my plan and all that? ... So review everything, check your kit, because we can't predict earthquakes, we don't know when they're going to happen, so we have to be prepared all the time."

NCTD temporarily halted Coaster and Sprinter train service following the quake, to inspect the tracks for signs of damage. No damage was found. They resumed resumed normal service around 5:52 PM, but with the Coaster experiencing 45-50 minute delays. 

More than 30 aftershocks were recorded by 5:30 p.m.  Most of them could not be felt by humans.  The strongest aftershock was 3.6 less than three minutes after the initial quake.