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1. Fault rock heterogeneity can produce fault weakness and reduce fault stability

   https://doi.org/10.1038/s41467-022-27998-2  

   Bedford, John D. ; Faulkner, Daniel R. ; Lapusta, Nadia ( December 2022 , Nature Communications)

   Abstract Geological heterogeneity is abundant in crustal fault zones; however, its role in controlling the mechanical behaviour of faults is poorly constrained. Here, we present laboratory friction experiments on laterally heterogeneous faults, with patches of strong, rate-weakening quartz gouge and weak, rate-strengthening clay gouge. The experiments show that the heterogeneity leads to a significant reduction in strength and frictional stability in comparison to compositionally identical faults with homogeneously mixed gouges. We identify a combination of weakening effects, including smearing of the weak clay; differential compaction of the two gouges redistributing normal stress; and shear localization producing stress concentrations in the strong quartz patches. The results demonstrate that geological heterogeneity and its evolution can have pronounced effects on fault strength and stability and, by extension, on the occurrence of slow-slip transients versus earthquake ruptures and the characteristics of the resulting events, and should be further studied in lab experiments and earthquake source modelling. 

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2. Along-fault migration of the Mount McKinley restraining bend of the Denali fault defined by late Quaternary fault patterns and seismicity, Denali National Park & Preserve, Alaska

   https://doi.org/10.1016/j.tecto.2016.05.009  

   Burkett, Corey A. ; Bemis, Sean P. ; Benowitz, Jeff A. ( December 2016 , Tectonophysics)
3. Machine Learning‐Based New Earthquake Catalog Illuminates On‐Fault and Off‐Fault Seismicity Patterns at the Discovery Transform Fault, East Pacific Rise

   https://doi.org/10.1029/2023GC011043  

   Gong, Jianhua ; Fan, Wenyuan ; Parnell‐Turner, Ross ( September 2023 , Geochemistry, Geophysics, Geosystems)

   Oceanic transform faults connect spreading centers and are imprinted with previous tectonic events. However, their tectonic interactions are not well understood due to limited observations. The Discovery transform fault system at 4°S, East Pacific Rise (EPR), represents a young transform system, offering a unique opportunity to study the interplay between faulting and other tectonic events at an early phases of an oceanic transform system. Discovery regularly hostsM5–6 characteristic earthquakes, and the seafloor north of Discovery includes a 35 km‐long rift zone that records a complex history of rifting, faulting and volcanism, suggesting that the transform faults likely interact with regional tectonic activity. We apply a machine‐learning enabled workflow to locate 21,391 earthquakes recorded during a 1‐year ocean bottom seismometer experiment in 2008. Our results indicate that seismicity on the western Discovery fault is separated into seven patches with distinct aseismic and seismic slip modes. Additionally, we observe a patch of off‐fault seismicity near where seafloor abyssal hills intersect the rift zone. This seismicity may have been caused by varying opening rates as spreading rate decreases from north to south in the rift zone. Our findings suggest that the Discovery system is still evolving, and that system equilibrium has not been reached between rifting and faulting. These results reflect the complex yet rarely observed interactions between fault slip, plate rotation, and rifting which are likely ubiquitous at oceanic transform systems.

    

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4. Steady Long‐Term Slip Rate on the Blue Cut Fault: Implications for Strain Transfer Between the San Andreas Fault and Eastern California Shear Zone

   https://doi.org/10.1029/2022GL100799  

   Guns, K. A. ; Bennett, R. ; Blisniuk, K. ; Walker, A. ; Hidy, A. ; Heimsath, A. ( October 2022 , Geophysical Research Letters)
5. Progressive microscopic damage associated with fault growth: MICROSCOPIC DAMAGE AND FAULT GROWTH

   https://doi.org/10.1029/2012GL052487  

   Tamarkin, T. ; Ougier-Simonin, A. ; Zhu, Wenlu ( August 2012 , Geophysical Research Letters)