San Francisco, July 6 (IANS) A massive earthquake measuring 7.1 on the Richter scale jolted southern California, just a day after a 6.4-magnitude temblor hit the US state, the strongest in 20 years.

According to the United States Geological Survey (USGS), the epicenter of the quake that hit the state at 8.19 p.m. on Friday was near Ridgercrest, a city located 272 km north of Los Angeles, Xinhua news agency reported.

Thursday's quake jolted a remote area in California's Searles Valley. It produced more than 1,400 aftershocks, scientists said.

--IANS ksk