Work

Not All Heterogeneity Is Equal: Length Scale of Frictional Property Variation as a Control on Subduction Megathrust Sliding Behavior

Year: 2025

Type: article

Abstract: Heterogeneity in geometry, stress, and material properties is widely invoked to explain the observed spectrum of slow earthquake phenomena. However, the effects of length scale of heterogeneity on macroscopic fault sliding behavior remain underexplored. We investigate this question for subduction megathrusts, via linear stability analysis and quasi‐dynamic simulations of slip on a dipping fault characterized by rate‐and‐state friction. Frictional heterogeneity is imposed through alternating velocity‐strengthening and velocity‐weakening (VW) patches, over length scales spanning from those representative of basement relief (several km) to the entrainment of contrasting lithologies (100s of m). The resulting fault behavior is controlled by: (a) the average frictional properties of the fault, and (b) the size of VW blocks relative to a critical length scale. Reasonable ranges of these properties yield sliding behaviors spanning from stable sliding, to slow and seismic slip events that are confined within VW blocks or propagate along the entire fault.

Source: Geophysical Research Letters

DOI: 10.1029/2025gl115738

Authors: Rob M. Skarbek, Demian M. Saffer, Heather M. Savage

Institutions: Planetary Science Institute, University of Texas Institute for Geophysics, The University of Texas at Austin, University of California, Santa Cruz

Language: English

Topic: earthquake and tectonic studies

Subfield: Geophysics

Field: Earth and Planetary Sciences

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $3,190

Funder: National Science Foundation