If The San Andreas Breaks, These California Cities Get Hit First

The San Andreas Fault has been quiet for centuries. But if the southern section suddenly ruptures, the first cities hit may not be Los Angeles. The rupture would begin near the Salton Sea and race through the Coachella Valley, putting communities such as Bombay Beach, Coachella, Indio, Palm Desert, Palm Springs, and Desert Hot Springs directly in the path of the earthquake. Roads could be torn apart, bridges damaged, and critical water infrastructure crossing the fault could be severely disrupted. Then comes the San Gorgonio Pass—a narrow corridor carrying major highways, rail lines, power infrastructure, and other critical connections into Southern California. The danger becomes even more severe in San Bernardino. The city sits over soft, water-saturated sediment where intense earthquake shaking can trigger liquefaction, causing normally solid ground to behave more like a liquid. Buildings, roads, pipelines, and underground utilities could suffer catastrophic damage. From there, the rupture reaches the Cajon Pass, one of Southern California's most important transportation corridors. Interstate 15, freight railroads, pipelines, and communication infrastructure all pass through this narrow mountain route. A major earthquake could turn the pass into a critical bottleneck, cutting transportation between the Los Angeles region and the rest of the country. Only after the rupture travels north would Los Angeles experience the full force of the seismic waves. The city's massive sedimentary basin could amplify and prolong the shaking, putting additional pressure on buildings and infrastructure. There is also a crucial difference between cities close to the fault and those farther away. California's ShakeAlert system can provide some warning as seismic sensors detect the first P-waves, but communities near the rupture may have only seconds—or potentially no useful warning before the strongest shaking arrives. This is the real threat of the California Big One: not one damaged neighborhood, but a cascading disaster moving across hundreds of miles of interconnected infrastructure. Watch until the end to see which California cities and critical corridors could be hit first when the San Andreas Fault finally breaks.