Fluid-Rich Subduction–Transform Fault Interactions During the 2024 Mw 7.0 Mendocino Earthquake

Jinzhi Ma, Elizabeth Su, Liuwei Xu, & Lingsen Meng

Submitted September 7, 2025, SCEC Contribution #14282, 2025 SCEC Annual Meeting Poster #TBD

The 2024 Mw 7.0 Mendocino earthquake occurred along the Mendocino transform fault near its junction with the Cascadia subduction zone. Using high-precision earthquake catalog construction techniques, finite fault inversion, back-projection, and geodetic data, we find that the rupture was influenced by sustained fluid migration from the subducting slab into the overlying transform fault zone. The earthquake initiated with a slow rupture near a fluid-rich segment and transitioned into relatively rapid bilateral propagation across the fault. A concentrated high-slip patch overlapped with a zone of elevated pore pressure, indicating fluid-assisted weakening of the fault. High-frequency radiation concentrated near the hypocenter suggests strong stress heterogeneity and structural complexity at the onset. These results highlight the critical role of deep fluids in nucleating large earthquakes and underscore the importance of long-term monitoring in subduction—transform fault junctions.

Key Words
Mendocino earthquake, Transform fault, Fluid, Subduction zone

Citation
Ma, J., Su, E., Xu, L., & Meng, L. (2025, 09). Fluid-Rich Subduction–Transform Fault Interactions During the 2024 Mw 7.0 Mendocino Earthquake. Poster Presentation at 2025 SCEC Annual Meeting.

Related Projects & Working Groups
Seismology