White Paper: The importance of expanding the Earthquake Center region to include the northern San Andreas fault system

March 2020

By Gareth Funning and Roland Bürgmann

We suggest expanding the geographic scope of a future Earthquake Center to cover the northern San Andreas fault system up to the Mendocino Triple Junction. This will facilitate improved understanding of fault behaviors and improved hazard estimates for large urban areas in California. Including the major faults of northern and central California would increase the diversity of fault behaviors to investigate, and potentially lead to more complete understanding of slow-slip phenomena, the physics of multi-segment ruptures, the influence of evolving fault-zone geometry on earthquake characteristics, as well as stress evolution, triggering relationships and earthquake clustering over a wide range of spatial and temporal scales. Expanding the region of interest to include the northern San Andreas fault system would also draw sharper focus on a wide array of secondary seismic and aseismic hazards, such as liquefaction, landsliding, and rapid shallow afterslip. Given the connected nature of California’s infrastructure lifelines, earthquake hazards in areas that could be considered remote, such as the Sacramento-San Joaquin Delta, through which 25 million Californians’ water supply flows, can have a strong impact on the population hundreds of miles away. A statewide Earthquake Center for investigating such earthquake hazards would better serve the whole population of California. Furthermore, expansion of the region of focus for the Earthquake Center would also unify the methodologies, resolutions, and applications of consensus community models with those used in the Uniform California Earthquake Rupture Forecast (UCERF) and lead to more accurate and detailed seismic hazard assessments. Expansion to the larger plate-boundary zone will grow and diversify the Earthquake Center community by providing new intellectual stimulus and enrich the research enterprise and community engagement in the collaboratory.

→ Download the response to NSF20-036 DCL here.

Gareth Funning is an associate professor at the University of California, Riverside. He studies movements and deformation of the Earth's surface to understand earthquake processes, the bending of the crust by plate tectonics, slow movements of faults ('fault creep'), and human activities such as geothermal power production. He has been co-leader of the Tectonic Geodesy working group of the SCEC Planning Committee since 2015.

Roland Bürgmann is a professor in the Department of Earth and Planetary Science at the University of California, Berkeley. His current research is focused on active tectonics and problems relating to fault zone processes and crustal deformation using space geodetic measurements and mechanical models. He has been the co-leader of the Stress and Deformation Over Time working group since 2019, and previously a member of the SCEC Board of Directors (2012-2016)

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