"Virtual shear box" experiments of stress and slip cycling within a subduction interface melange

作者：Webber Sam^*; Ellis Susan; Fagereng Ake

来源：Earth and Planetary Science Letters, 2018, 488: 27-35.

DOI：10.1016/j.epsl.2018.01.035

• subduction
• melange
• stress
• numerical modeling
• Chrystalls Beach Complex
• strain transients

What role does the progressive geometric evolution of subduction-related melange shear zones play in the development of strain transients? We use a "virtual shear box" experiment, based on outcrop-scale observations from an ancient exhumed subduction interface - the Chrystalls Beach Complex (CBC), New Zealand - to constrain numerical models of slip processes within a meters-thick shear zone. The CBC is dominated by large, competent clasts surrounded by interconnected weak matrix. Under constant slip velocity boundary conditions, models of the CBC produce stress cycling behavior, accompanied by mixed brittle-viscous deformation. This occurs as a consequence of the reorganization of competent clasts, and the progressive development and breakdown of stress bridges as clasts mutually obstruct one another. Under constant shear stress boundary conditions, the models show periods of relative inactivity punctuated by aseismic episodic slip at rapid rates (meters per year). Such a process may contribute to the development of strain transients such as slow slip.

• 出版日期2018-4-15