An estimated 5.0-magnitude earthquake centered in northern Baja California shook the US-Mexico border region about 160 km east of San Diego.
There were no immediate reports of any injuries or damage, authorities said on Tuesday. Authorities in Mexico said they were checking for injuries or damage.
The quake, which struck at 2:41 pm local time, was centered 34 km southeast of Calexico, a US border city of more than 37,000 residents, the US Geological Survey said.
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."
The big temblor was followed within minutes by three aftershocks that ranged in magnitude from 3.1 to 3.7.
"It started off with a little jolt, then a rumble," said Sgt Mike Misteriel of the Imperial County Sheriff's Department. The aftershocks produced a rolling sensation, he said.
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.