News from USGS Pacific Coastal and Marine Science Center
Coring the Hayward-Rodgers Creek fault zone in San Pablo Bay, California, to unravel the history of faulting beneath the bay
From October 17-21, 2016, USGS scientists collected 20 core samples of bayfloor sediment along the Hayward-Rodgers Creek fault zone in San Pablo Bay, a northern extension of San Francisco Bay, California. The longest core measures nearly 4 meters. Detailed radiocarbon dating of benthic forams (one-celled microorganisms) in the core samples will aid in unraveling the history of faulting in the bay and constraining the age of the most recent surface-rupturing earthquake along this part of the fault zone. Recent high-resolution acoustic imaging revealed a direct link between the Hayward and Rodgers Creek faults and provided a framework for targeted sampling of offset sediment layers, unconformities, and peculiar gas pockets.