‘We should expect more quakes’: a top seismologist on California’s tremor

A magnitude 5.4 aftershock followed Thursday's 6.4 magnitude quake, the southern California region's largest in two decades

A 5.4-magnitude aftershock hit southern California on Friday morning, one day after the region experienced its largest earthquake in two decades.

Thursday's 6.4-magnitude quake landed in the small city of Ridgecrest, 100 miles (160km) from Los Angeles, and renewed fears about the potential for the "big one" to hit the west coast in the future.