A new study suggests excessive groundwater pumping for irrigation in California's agricultural belt can stress the San Andreas Fault, potentially causing future small earthquakes.
GPS readings found the San Joaquin Valley floor has been sinking for decades through groundwater loss while the surrounding mountains are being uplifted. A team led by Western Washington University says this motion produces slight stress changes on the San Andreas and neighboring faults.
The findings were released Wednesday by the journal Nature.
The San Andreas is the most significant fault crisscrossing California. Nearly 800 miles long, it stretches from a peninsula north of San Francisco to the Salton Sea near the U.S.-Mexico border.
The fault has unleashed some of the most devastating seismic disasters in state history including the 1906 San Francisco earthquake.