Mechanics of large earthquakes and seismic swarms at oceanic transforms controlled by hydrothermal alteration

Mingqi Liu, & Sylvain D. Barbot

Published September 8, 2024, SCEC Contribution #13683, 2024 SCEC Annual Meeting Poster #122

The generation of earthquakes is influenced by the thermo-mechanical and structural properties of fault zones. However, the lithological and hydrothermal controls on the style and size of ruptures and their recurrence patterns are still poorly understood. Here, we describe the role of hydrothermal alteration on the spatial distribution and style of seismicity along oceanic transform faults. We employ three-dimensional seismic cycle simulations calibrated with thermal profiles from thermo-mechanical geodynamic models and laboratory-derived frictional properties of crust and mantle rocks to explain the seismic patterns throughout the oceanic lithosphere. While the unstable nature of gabbro friction supports a narrow seismogenic zone in the oceanic crust, the size of seismic ruptures may be limited by patches of hydrothermal alteration products within the fault zone. In pockets of the serpentinized mantle, the frictional hardening of antigorite with shear heating facilitates the spontaneous generation of seismic swarms. The seismic pattern of oceanic transforms is strongly modulated by the circulation of fluids, controlling the local lithology and associated frictional behavior.

Key Words
Seismic cycle, oceanic transforms, earthquke swarms

Citation
Liu, M., & Barbot, S. D. (2024, 09). Mechanics of large earthquakes and seismic swarms at oceanic transforms controlled by hydrothermal alteration. Poster Presentation at 2024 SCEC Annual Meeting.

Related Projects & Working Groups
Fault and Rupture Mechanics (FARM)