Memory and jamming in fault zone sediments

Communications Earth & Environment
By: , and 

Links

Abstract

Many subsurface processes involve transitions in granular material states, from arrested to creeping to flowing. Experiments and frameworks for idealized systems reveal that granular fabrics develop during shearing, co-evolve with applied stress, and govern such transitions. We use microtomography to test whether fabrics at two San Andreas fault sites reflect slip history and whether idealized frameworks extend to nature. Near-surface sediments within the fault zone transition between deformation patterns over the seismic cycle, including bulk/localized grain re-arrangements, individual grain fracturing, and localized zones of fracturing. Aseismic and co-seismic shearing produce distinct preferred grain orientations. Co-seismic fabrics can be preserved after centuries of aseismic strain, aseismic fabrics may be overprinted, and grain size and coordination number influence the fabrics. Idealized frameworks, namely anisotropic critical state theory, frictional jamming, and material memory, can explain our observations, and fault zone sediments likely undergo cycles of memory creation and erasure that influence rigidity spatiotemporally.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Memory and jamming in fault zone sediments
Series title Communications Earth & Environment
DOI 10.1038/s43247-025-02952-4
Volume 6
Publication Date December 09, 2025
Year Published 2025
Language English
Publisher Nature
Contributing office(s) Earthquake Science Center
Description 998, 10 p.
Country United States
State California
Other Geospatial Pallett Creek site
Additional publication details