A moderate earthquake in northern Mexico was felt from San Diego to southwestern Arizona, but no injuries or damage were reported.
Seismologist Dale Grant of the US Geological Survey says the magnitude-5.1 quake struck just before 4 pm on Saturday. It was centered about 40 kilometre southeast of Calexico, California, and 37 kilometre southeast of Mexicali, Mexico, at a depth of 10 kilometre.
Several aftershocks followed, the largest a magnitude-4.2 about two hours after the initial quake.
The USGS has received reports of people feeling the quake from 193 kilometre west of the epicentre in San Diego, to 96 kilometre east in Yuma, Arizona.
Dispatchers with the Calexico Police Department say the station shook briefly but there were no reports of damage or injuries.
Calexico is 193 kilometre east of San Diego and has a population of 27,000.