"The quake was felt strong in Pasadena here," Derderian said, adding it's first day of school for the Pasadena Unified School District. "(We're) hoping that teacher and school personnel are talk to them what to do and aftershocks."
Shaking was felt across the Los Angeles region as well as northern Orange County, Robert De Groot from the U.S. Geological Survey said, adding the ShakeAlert early warning messages were sent out.
It was initially reported as magnitude-4.7 with the quake's depth being 9km.
The Los Angeles Police Department is urging to be prepared for aftershocks.