Technical Activity Group (TAG): Northern California Cascadia - San Andreas Transition (NORCAT)

Debi Kilb, Matthew Herman, Kathryn Materna, jason R. patton, Vera Schulte-Pelkum, David R. Shelly, & Amanda M. Thomas

Submitted August 30, 2026, SCEC Contribution #15395, 2026 SCEC Annual Meeting Poster #TBD

The NORCAT Technical Activity Group (TAG) focuses on advancing research on the northern California transition between Cascadia subduction, the San Andreas Fault system, and the Mendocino Triple Junction. This interlinked system connects the two largest seismic hazards in the western United States. Recent advances—including new machine-learning earthquake catalogs, observations of tremor and low-frequency earthquakes, improved seismic imaging onshore and offshore, geodetic measurements, and increasing resolution and new models of lithospheric structure—have fundamentally expanded our understanding of this tectonic transition while raising new questions about fault geometry, plate-boundary architecture, and interactions between transform and subduction systems. These discoveries provide an unprecedented opportunity for community-wide synthesis and coordinated research. NORCAT aims to bring together researchers from the SCEC, CRESCENT, and general communities, with expertise in seismic structural imaging, analysis of seismicity, tremor, low frequency earthquakes, creep, kinematic plate modeling, geodesy, magnetics and other potential methods, thermal constraints, and paleoseismology. The TAG focuses on coordinating research directions, developing testable competing models, and coordinating funding efforts, all in order to address SCEC objectives of integrating CEMs (OJB-01), developing earthquake scenarios (OBJ-02) in the region, and integrating multidisciplinary early-career and seasoned researchers (OBJ-07).

Key Words
San Andreas, Cascadia, TAG

Citation
Kilb, D., Herman, M., Materna, K., patton, j. R., Schulte-Pelkum, V., Shelly, D. R., & Thomas, A. M. (2026, 08). Technical Activity Group (TAG): Northern California Cascadia - San Andreas Transition (NORCAT). Poster Presentation at 2026 SCEC Annual Meeting.

Related Projects & Working Groups
Community Earth Models (CEM)