Seismicity along the Southern Edge of the Subducted Gorda Plate
Jianhua GongSubmitted August 30, 2026, SCEC Contribution #15506, 2026 SCEC Annual Meeting Poster #046
The southernmost Cascadia subduction zone is where the Gorda, Pacific, and North American plates converge at the Mendocino Triple Junction (MTJ). This region is one of the most seismically active areas in North America, characterized by frequent large earthquakes and abundant microseismicity. Along the southern edge of the subducted Gorda plate, the plate is in contact with the Pacific plate offshore, the Pioneer microplate near the coastline, and the lower crust of the North American plate as it descends into the mantle. These transitions in plate-boundary contacts produce distinct fault-slip behaviors along the slab edge, including M7-class earthquakes, earthquake swarms, repeating earthquakes, tectonic tremor, and slow-slip events. In this study, we construct a long-term earthquake catalog for the southern edge of the subducted Gorda plate to better constrain the fault geometry and characterize the spatial and temporal evolution of seismicity in this complex plate-boundary region.
Citation
Gong, J. (2026, 08). Seismicity along the Southern Edge of the Subducted Gorda Plate. Poster Presentation at 2026 SCEC Annual Meeting.
Related Projects & Working Groups
Plate Boundary System (PBS)
