4.2-magnitude earthquake rattles Southern California

FONTANA, Calif., July 25 (UPI) -- Residents were jolted awake Saturday morning when a 4.2-magnitude earthquake rattled Southern California, with some feeling the tremors up to 100 miles away.

The quake, at 5:54 a.m. local time, was so jarring items were falling off shelves and windows were rattling, sending social media into a frenzy. There was no reported damage or injuries. The United States Geological Survey said the epicenter was one mile from Fontana, Calif., a population 200,000 city about 50 miles outside Los Angeles.

"We felt it very strong. We thought it was an explosion," local resident Patty Madrid told NBC Los Angeles.

All of a sudden the #birds stopped singing & within a few mins we felt the #Fontana #earthquake at http://t.co/jnEFlzqhhm

— PineAndCrowStudios (@PineAndCrow) July 25, 2015

Felt the #earthquake here in Fontana

— Mari (@Microcrisis) July 25, 2015

Seismologist Jennifer Andrews, with the California Institute of Technology, said the quake was about three miles deep and shallow, "which can be widely felt." She described the movement as a jolt.

"Being a magnitude 4.2 and very shallow, they felt some reasonable shaking," Andrews told NBC. There is a small chance the earthquake was a precursor to a larger one.

#RudeAwakening: 4.3 #Earthquake this morning in #Fontana, #CA; only 4 mi in depth. http://t.co/K7Fn6VQ3ly

— Edie Schaffer (@sf_edie) July 25, 2015