A team of Franklin & Marshall geologists has discovered a new active fault in Northern California which was announced at an annual meeting of the Seismological Society of America in San Francisco.
The new fault is located between the towns of Fort Bragg and Westport. This new fault, dubbed the Pacific Star Fault, is part of the San Andreas fault system. The newly discovered fault was revealed after Dr. Merritt and her team analyzed several abandoned paleo stream channels using GPS ground surveying of marine terraces, fieldwork, and large scale aerial photos of the area.
When the geologists came by the Pacific Star Winery and asked if they could look around for evidence of a fault, a geology major in college, Robert Zimmer had noticed what he thought was a fault (albeit and old, inactive one) on the western edge of the property. When he showed it to them, “their eyes grew as big as saucers”. It was not an old inactive fault, but a striking cross section of the fault they’d guessed might be here.
Three visible sections run parallel to the San Andreas Fault, which is located some 8 miles west of the winery under the Pacific Ocean. According to Dr. Merritt, the Pacific Star Fault has moved and average of 10mm per year, or about half an inch. No major movement has taken place though for a number of years.
Dr. Merritt and her team plan to continue their research of the Pacific Star Fault in the coming year in order to better understand the hazards associated with the fault system.