An earthquake measuring 6.9 on the Richter scale has struck the Gulf of California off Mexico.
Earthquake strikes off Mexico coast
The US Geological Survey said the strong quake struck inside the Sea of Cortez, 76 miles from the town of Santa Isabel on the Baja California peninsula and was 6.2 miles deep.
There were no initial reports of deaths or serious damage.
Baja California is home to desert and mountains, and is sparsely populated.
The quake was felt strongly in San Diego just across the border from Mexico.
"It felt very calm, there was barely a vibration," said hotel receptionist Graciela Alvarado at a motel in the town of Caborca, in the Mexican state of Sonora, across from Baja California.
The series of quakes began with a 5.8-magnitude tremor followed by one registering a magnitude of 6.9 five minutes later.
Two more tremors, measuring 5.0 and 5.9 magnitude, followed within an hour, said the US Geological Survey, Mexico's National Seismological Center and the US Tsunami Warning Centre.
Local authorities warned there was a risk of a small, localised tsunami in the area but no official tsunami warning for the main Pacific coastline.