Scientists have discovered an alarming connection underwater: Two of the most dangerous earthquake faults in the Bay Area. Experts long debated whether the Hayward Fault and the Rodgers Creek Fault connected, but now there’s strong evidence they do. US Geological geophysicist Janet Watt made the discovery in an underwater survey using an acoustic instrument over the San Pablo Bay. She says the data is clearer than ever.

“We now have direct evidence that the faults come closer together in the bay and may be directly connected,” says Watt. “It would be devastating for an earthquake to rupture at both those faults — it’d be a very strong earthquake.” Two Bay Area fault lines could potentially trigger a 7.3 magnitude earthquake if they ruptured together. That’s stronger than the 1989 Loma Prieta quake. FULL REPORT