Earthquakes

California fault capable of 8.0 earthquake shows movement for first time

A photo of the San Andreas fault.
A photo of the San Andreas fault. Photo: Stocktrek/Getty Images

The 160-mile-long Garlock fault in California has shown movement for the first time on the modern historical record, according to a study published Thursday by the California Institute of Technology.

Why it matters: The fault is capable of producing an 8.0 magnitude earthquake, but it has never previously produced a strong quake or creep. Now, satellite images show the fault has begun moving, resulting in a visible bulge. The movement is said to be a result of a July earthquake that destabilized surrounding faults.

6.0-magnitude earthquake jolts Puerto Rico

The blue tarp that was used to protect the roof damaged by Hurricane Maria two years ago is showing wear and tear in San Juan, Puerto Rico, September 18
The blue tarp that was used to protect the roof damaged by Hurricane Maria 2 years ago is showing wear and tear, San Juan, Puerto Rico, Sept. 18. Photo: Ricardo Arduengo/AFP/Getty Images

A 6.0-magnitude earthquake struck near Puerto Rico Monday night, with several aftershocks following — including one of 5.1, the National Weather Service in San Juan said. The island’s Emergency Management Agency told AP there were no reports of damage.

Why it matters: Puerto Rico is still recovering from the devastation caused by Hurricane Maria 2 years ago, and it's preparing for the arrival of Tropical Depression Karen — which threatens to trigger heavy rain, flash flooding and mudslides.