US Geological Survey data shows the first quake struck around 12:08 p.m. local time Saturday in Heber near the US-Mexico border, about 60 miles south of the Salton Sea, measuring 4.1 magnitude. There were dozens of tremors reported after the initial shock.
Then on Sunday morning, a 4.5 magnitude quake struck 4 miles west-southwest of Niland and just east of the Salton Sea, USGS data showed. Dozens of tremors were reported as well.
According to a USGS intensity map, the quakes were felt in Palm Desert, Indio, El Centro, and Mexicali.
As for the state's southern region, it remains to be seen whether these swarms signal the potential for larger quakes.