A swarm of earthquakes started on Monday at 6:07 p.m. near the California-Mexico border. There were 18 aftershocks within the first two hours, Caltech seismologist Egill Hauksson said. By Tuesday morning, there had been dozens of aftershocks, including a magnitude 3.3 quake that hit just before 2 a.m.

For more info, please read the original article by LA Times:
https://www.latimes.com/california/story/2019-11-11/several-small-earthquakes-strike-el-centro