Back in 1905, the Colorado River, swollen with heavy rainfall and snowmelt, surged into a dry lake bed along California’s San Andreas Fault and formed the Salton Sea. The flood waters submerged most of the small town of Salton, along with nearby tribal lands. The inundation also covered a key, seismically active stretch of the San Andreas Fault’s southern tip in silt, hiding evidence of its potential volatility. Utah State University geologist Susanne Jänecke began hypothesizing the location and geometry of the

sediment-obscured fault zone more than a decade ago. After securing funding from the Southern California Earthquake Center in 2011, she, along with USU graduate student Dan Markowski and colleagues, embarked on the painstaking task of documenting the uplifted, highly folded and faulted area with geologic mapping and analysis. The geologists’ persistence revealed a nearly 15.5-mile-long, sheared zone with two, nearly parallel master faults and hundreds of smaller, rung-like cross faults. Dubbed the “Durmid Ladder” by the team, the well-organized structure could be the site of the region’s next major earthquake. CONTINUE