LOS ANGELES, Sept. 2 (Xinhua) -- At least four aftershocks were measured following a magnitude 4.7 earthquake in southern California Sunday morning, but with no immediate injuries or damages reported.

    The earthquake rattling the whole region occurred at 10.29 a.m. and was centered under the Santa Ana mountain range about 90 kilometers southwest of downtown Los Angeles.

    Automated seismographs reported that the earthquake's tentative epicenter was estimated to be about 13 kilometers west-northwest of the Riverside County city of Lake Elsinore, the Los Angeles CNS news service said.

    A reporter felt a strong shock at an office in Riverside, about40 kilometers northeast of the epicenter. It was also felt in Los Angeles and many of nearby areas.

    "There were no injuries reported to us at this time," said Jody Hagemann, spokeswoman for the Riverside County Fire Department.

    The spokeswoman said the department has sent out an order to all of the fire stations so firefighters take all apparatus out of the basement until they are sure that everything is cleared.

    A Riverside County Sheriff's Department spokesman said they have not received reports of any damages.

    Reports said at least four aftershocks have followed the earlier earthquake, with the largest being a 2.5 magnitude one two minutes after the first shock.

    Data from the automated seismographs has not been verified by scientists, and experts in the past have cautioned that aftershock data is not always precise.

    The network of seismographs and computers in the region showed that a magnitude 2.5 aftershock hit at 10:31 a.m., followed by three minor aftershocks, according to local media reports.

    Seismologists believe there is a chance a major earthquake would hit California due to movement in the San Andreas fault, which runs close by Los Angeles. Experts say the fault line causes a massive quake every 150 years with last such disaster taking place in 1857.

    In January 1994, a 6.7 magnitude quake in Northridge, near Chatsworth, was blamed for 72 deaths, more than 10,000 injuries and around 12.5 billion dollars worth of damage.