PhD student Katherine Guns has been awarded an EarthScope AGeS Program grant in support of her research studying the Coachella Valley segment of the Southern San Andreas Fault. Katherine's $9,405 grant was awarded to pay for completing the geochronology portion of her research.
Katherine describes her research here: "The Southern San Andreas Fault is a critical component of the plate boundary system in southern California because it is one of two faults that accommodate the majority of plate motion at the latitude of Palm Springs. However, the segment through the Coachella Valley has not ruptured in over 300 years and is considered overdue for a large earthquake. More puzzling is the fact that 3 M6+ earthquakes have occurred in the nearby Eastern California Shear Zone in the last 25 years, leading researchers in the community to propose several hypotheses to explain this behavior. I hypothesize that while strain is still accumulating on the San Andreas Fault, some of that strain is being drained off the fault towards the Eastern California Shear Zone through block rotation of in the Eastern Transverse Ranges, a terrain lying between the two systems. To test this hypothesis, I am first working to determine whether block rotation is still occurring in the Eastern Transverse Ranges by collecting and analyzing Campaign GPS data from the University of Arizona-managed GPS network in Joshua Tree National Park and by completing slip rate studies along the left lateral faults that would be responsible for accommodating block rotation. In being awarded the EarthScope Awards for Geochronology Student Researchers (AGeS) Grant, I will now be able to date 10 samples using 10Be Cosmogenic radionuclide surface exposure dating and will be able to estimate a Quaternary slip rate for one site along one of the left lateral faults in my study. This will allow me to determine at a first glance what the most recent slip history of this fault system might be and how these faults relate to the regional fault system around the San Andreas."