[S-CG54] New Insights of Fluid-Rock Interactions: From Surface to Deep Subduction Zone

[SCG54-05] Shear Crack Fractography

*mitsuhiro toriumi¹ (1.Japan agency of marine science and technology )

Keywords:fractography, shear crack, jog and kink

Toriumi (2022, 2025) proposed the periodic and systematic distribution of jogs sealed by stable minerals and kinks on the various seismic and non-seismic slip plane from the geological investigation of the largely sheared zone of the plate boundary metamorphic rocks. In these papers, it showed that the shear crack surface exposed in the outcrops of the metamorphic areas displays obviously the periodic and wavy ridges running oblique and normal to the slip directions that is assigned by the mineral stretching lineation. These ridges are covered by the curved main shear slip planes and associated Riedel and penetrative shear planes, and the core parts of the ridges constitute the shear crack jogs sealed with metamorphic minerals such as albite, quartz, amphiboles, and calcite. These ridges often show the offset along on the shear surface, and thus it should be assigned by the kink of the shear crack. These characteristic features of the shear slip planes, that is the shear crack topography, are to be investigated for clarifying the physical process of the various seismic slip phenomena observed by seismicity observatory.
The author will intend to propose as the new disciplinary works on the experimental shear crack topography, “shear crack fractography” likely to the open crack fractography in the metallurgy field. The open crack fractography has been established now in the metallurgy, although it seems that the shear crack fractography is still going on foundation in the disciplinary field of the materials science.