Rupture process of the Mw7.0 December 5, 2024 Offshore Cape Mendocino earthquake

Frederick Pollitz; Katherine Anna Guns; Clara Yoon

doi:10.1029/2025gl115613

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Rupture process of the Mw7.0 December 5, 2024 Offshore Cape Mendocino earthquake

Frederick Pollitz·Katherine Anna Guns·Clara Yoon

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Abstract

The Mw7.0 December 5, 2024 Offshore Cape Mendocino earthquake ruptured a km long portion of the east-west trending Mendocino fault zone (MFZ). In order to clarify the rupture process, we assemble three-component seismograms from regional seismic stations, horizontal coseismic displacement vectors derived from Global Navigation Satellite System (GNSS) time series, and a Sentinel-1 ascending interferogram. These data are interpreted with a model of slip distributed on two vertical fault planes representative of the eastern MFZ and spanning the ~70 km length of the aftershock zone. Assuming right-lateral strike slip, we find that the rupture initiates in the oceanic mantle at 20-30 km depth and proceeds unilaterally updip and toward the east. Early aftershocks locate adjacent to the peak slip areas, tracking the coseismic rupture propagation from oceanic mantle to shallower depth and implying a significant role of static stress transfer in driving aftershocks in an ocean plate environment.

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Geophysical Research Letters Article

Source-reported bounding extent: 38° to 42° latitude; -126° to -121° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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Frederick Pollitz, Katherine Anna Guns, Clara Yoon. 2025-07-24. Rupture process of the Mw7.0 December 5, 2024 Offshore Cape Mendocino earthquake. https://doi.org/10.1029/2025gl115613

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