Newly identified fault line in California could unleash monster earthquake

Southern California could be in for some serious shaking.

Scientists uncovered a newly identified fault line that could unleash a magnitude-7.4 earthquake in the region, which other researchers say is already long overdue for a whopper of a temblor along the infamous San Andreas fault.

The concerns are detailed in separate studies that put the quake risks of the USA's most populous state into much sharper focus.

The newly identified fault line is capable of a powerful quake that would impact 20 million residents of Los Angeles and San Diego, according to a study published Tuesday. The fault runs underwater from San Diego Bay to Seal Beach in Orange County and on land through the Los Angeles basin, researchers found.