( Reuter )- A powerful earthquake centered in northern Baja California shook the U.S.-Mexico border region about 100 miles east of San Diego on Tuesday.
There were no immediate reports of any injuries or damage, authorities said. Authorities in Mexico said they were checking for injuries or damage.
The quake, which struck at 2:41 p.m., was centered 21 miles southeast of Calexico, a U.S. border city of more than 37,000 residents, the U.S. Geological Survey said.
The U.S. Geological Survey reported the quake was magnitude 5.0 but USGS geophysicist Rafael Abreu said it occurred in the area of a seismic network operated by Mexico which put it at 5.3.
Such differing magnitude reports and later adjustments of magnitude are common.
Calexico resident Enrique Alvarado said he leapt away from a plate-glass window in his office as the shaking began.
"It was a little scary - you stand in the doorways," said Alvarado, who runs a vocational school. "I estimate it went on 25 or 30 seconds, but it feels like an eternity when you're in it."
Three other quakes with magnitudes of 5.4, 5.1 and 5.0 have rattled the area in the past two weeks, causing blackouts and temporarily knocking out cell phone service.
Some Calexico residents who are used to the region's frequent quakes said they're rattled by the recent ones.
"A lot of my neighbors and co-workers, people in two-story homes, tell me they've been sleeping on the ground floor," said Cesar Aguilar, manager of a duty-free shop. " Me , my wife and kids are all sleeping together in the same room."
Customers have been stocking up on water, batteries, camping equipment and dry food at the local Wal-Mart.
"We ran out of flashlights," assistant manager Manuel Martinez said. "We're calling different places to order some more."
Calexico Fire Chief Peter Mercado said some residents were overreacting to the recent earthquakes because they're influenced by radio reports from Mexicali, where some structures have been visibly damaged by earthquake activity.
Following one moderate quake last week, up to 30 residents of a three-story retirement home went outside and huddled in the cold, refusing to return to their homes, Mercado said.
"We inspected the building and tried to reassure them that they're safer in the building than outside," he said.